ChatGPT answers, unedited

For an agency managing multiple clients’ paid newsletters, the “best” software depends on whether you mean:

1. You operate newsletters as a service (you own the workflow, clients pay you), or
2. You provide a platform where each client owns their newsletter, subscribers, billing, and access.

The key requirements are usually:

• Separate client workspaces (no data mixing)
• Separate subscriber lists and sender identities
• Client-level billing or chargeback
• Role-based access (writer/editor/approver/client admin)
• Paid subscriber management
• Subscription payments and entitlement control
• Reporting per client
• White-label options

Here are the strongest options:

My shortlist by agency type

1. Newsletter production agency (you run 20–100 newsletters)

Look first at:

• Letterhead — built around multiple newsletter brands, separate workspaces, reporting, and monetization workflows. Letterhead
• NewsBox — designed around agencies managing client-owned newsletter organizations with role-based access. NewsBox

2. Email marketing agency (newsletters are one service among many)

Look at:

• Campaign Monitor — strong agency workflow: separate client accounts, permissions, templates, reporting, and client billing support. Campaign Monitor
• ActiveCampaign — better if newsletters are part of broader automations, CRM, and lifecycle campaigns. BestSends

3. Paid newsletter network (each client sells subscriptions)

A common architecture is:

• Newsletter platform: Letterhead / beehiiv
• Payments: Stripe
• Identity/access: customer accounts + subscription entitlements
• Agency layer: client portal + reporting dashboard

This keeps:

• Client A’s subscribers separate from Client B’s
• Revenue attribution clean
• Client ownership transferable if they leave

Features I would prioritize before choosing

1. Do not use one giant newsletter account with tags.

It becomes risky when clients need separate billing, permissions, and ownership.

2. Require subaccounts/workspaces.

A good agency setup should let you remove a client without exporting and rebuilding everything.

3. Check payment ownership.

Decide whether:

• the client receives subscription revenue directly, or
• your agency collects revenue and pays clients.
• Look for approval workflows.

Clients often want “review before send,” not full admin access.

For most agencies, I’d narrow the evaluation to:

• Letterhead if newsletters are the core product
• Campaign Monitor if you are a traditional marketing agency
• NewsBox if clients should retain ownership while your team operates their newsletters
• ActiveCampaign if newsletters are part of a larger marketing automation service Campaign Monitor NewsBox BestSends

If you tell me your model (e.g., “we manage 50 paid Substack-style newsletters” vs “we run email marketing for clients”), I can narrow this to a specific stack.

If your agency manages multiple paid newsletters for different clients, the key requirement is not just “newsletter software”—it’s multi-client tenancy + separate billing + granular access.

My shortlist

1. beehiiv — probably the closest match

beehiiv explicitly supports agencies managing newsletters for multiple clients. You can put multiple publications in an account, with each publication having its own subscriber list, settings, domains and analytics. Beehiiv

More importantly for your use case, beehiiv now supports publication-level permissions. A team member can be granted access to only specific publications, rather than seeing every client. Beehiiv Beehiiv

The important distinction is billing/ownership:

• Agency owns everything: put multiple client publications in your workspace.
• Client owns their newsletter: have each client use their own beehiiv account/workspace and invite your agency as a team member.
• This second model keeps the client's billing, subscriber data and ownership separate, which is generally the cleaner agency arrangement. beehiiv explicitly recommends separate accounts when a client needs their own login, billing or full ownership. Beehiiv

beehiiv also has an agency partner program with multi-client tracking and white-label collateral. Beehiiv

beehiiv.com

2. Ghost — better if each client needs a full branded publication

Ghost is compelling if your agency is essentially building and operating a separate publication/site for each client.

Each Ghost publication can have its own:

• paid/free memberships
• Stripe billing
• subscriber database
• newsletters
• newsletter-specific subscriptions
• gated content

Ghost's membership system supports paid subscriptions and server-side access control, while billing can connect to the publication's own Stripe account. Ghost Developer Docs

It also supports multiple newsletters within a publication, each with separate subscriptions and settings. Ghost

The downside for an agency is that Ghost isn't as naturally designed around a single agency dashboard controlling dozens of client publications as beehiiv's multi-publication/workspace model.

ghost.org

What I'd do for an agency

I'd structure it like this:

Agency
│
├── Client A — beehiiv Workspace A
│   ├── Client billing
│   ├── Client subscribers
│   └── Agency team access
│
├── Client B — beehiiv Workspace B
│   ├── Client billing
│   ├── Client subscribers
│   └── Agency team access
│
└── Client C — beehiiv Workspace C
    ├── Client billing
    ├── Client subscribers
    └── Agency team access

That gives you clean ownership boundaries. The agency operates everything, but if Client B leaves, you aren't disentangling their subscribers, Stripe account, publication and billing from a giant agency-owned account.

If you're expecting 10–50+ clients, I'd specifically evaluate the workflow around switching between separate client workspaces, permissions, reporting, API access and billing—not just the newsletter editor.

Bottom line: for a pure paid-newsletter agency, I'd start with beehiiv. If each client needs a highly customized publication/site and your agency is comfortable operating separate sites, Ghost becomes more attractive.

If you tell me roughly how many clients you expect (e.g. 5, 25, 100) and whether the client or agency should own the Stripe/subscriber account, I can narrow this down to an actual recommended architecture and pricing model.

For an agency managing multiple clients’ paid newsletters, the key requirements are usually different from a solo newsletter creator:

• Separate client workspaces (no audience/data mixing)
• Separate billing ownership or chargeback
• Role-based access (agency team vs client users)
• Paid subscriptions + member access control
• White-label reporting/client dashboards
• Easy offboarding (client keeps their publication)

The strongest options I’d shortlist:

My picks by agency model

1. You are a “newsletter-as-a-service” agency

Pick: Letterhead or NewsBox

You want:

• 20–100 client newsletters
• Separate client dashboards
• Client reporting
• Staff permissions
• Repeatable production workflows

Letterhead is probably the closest match because it positions itself around agencies managing client newsletters with separate workspaces and reporting. Letterhead

2. You build premium paid publications for clients

Pick: Ghost

Good architecture:

• Client A → separate Ghost publication → Stripe account → members
• Client B → separate Ghost publication → Stripe account → members
• Agency → admin/editor access

Pros:

• Client owns subscribers
• Excellent membership controls
• Portable content/data

Cons:

• More operational overhead for an agency managing dozens of clients.

3. You mainly send newsletters but don’t need a full membership site

Pick: Campaign Monitor or MailerLite

These are better if the “paid newsletter” part means:

• clients pay your agency,
• you manage campaigns,
• subscribers are mostly a mailing list.

They are less ideal if readers need login-based access to premium content.

Architecture I’d recommend for a serious agency

For 10+ clients, avoid one giant shared account. Use:

Agency admin layer
        |
        +-- Client A workspace
        |       +-- Stripe billing
        |       +-- Subscriber database
        |       +-- Team permissions
        |
        +-- Client B workspace
        |       +-- Stripe billing
        |       +-- Subscriber database
        |
        +-- Client C workspace

The biggest mistake agencies make is owning every subscriber relationship themselves. A better model is usually: client owns the publication and billing; agency has delegated management access. NewsBox explicitly follows this model, where clients retain ownership while agencies manage newsletters. NewsBox

Short answer

• Best overall for a paid-newsletter agency: Letterhead
• Best for client ownership + agency permissions: NewsBox
• Best premium membership engine: Ghost
• Best traditional agency email operations: Campaign Monitor
• Best lightweight option: MailerLite

If you’re managing fewer than ~10 clients, I’d optimize for simplicity. If you’re managing 50+ client newsletters, I’d prioritize true multi-tenant workspaces and client ownership over creator-focused newsletter platforms.

Agency admin layer
        |
        +-- Client A workspace
        |       +-- Stripe billing
        |       +-- Subscriber database
        |       +-- Team permissions
        |
        +-- Client B workspace
        |       +-- Stripe billing
        |       +-- Subscriber database
        |
        +-- Client C workspace

The biggest mistake agencies make is owning every subscriber relationship themselves. A better model is usually: client owns the publication and billing; agency has delegated management access. NewsBox explicitly follows this model, where clients retain ownership while agencies manage newsletters.

Short answer

For an agency managing multiple clients’ paid newsletters, the key requirement is different from a creator picking a newsletter tool. You usually need:

• Separate client publications
• Separate Stripe/payment accounts or revenue ownership
• Subscriber access rules (free vs paid tiers, team seats, gated archives)
• Multiple staff roles
• Client approval workflows
• Reporting by client
• Easy handoff if a client leaves

The strongest options depend on whether you want an agency operating layer or just a great newsletter platform per client.

My shortlist

1. Ghost — best for premium paid newsletters with client ownership

Ghost is a strong fit if each client is essentially running a publication.

Strengths:

• Paid memberships built in
• Tiered access control
• Client owns subscriber relationship
• No platform revenue cut on subscriptions
• Custom domains and branding
• Good separation between publications

Weakness:

• It is not really an “agency dashboard.” You’ll likely manage separate client sites rather than one master console. Publishing House

Ideal setup:

• One Ghost site per client
• Client-owned Stripe account
• Agency gets admin/editor access
• Monthly reporting layer in your own dashboard

2. beehiiv — best newsletter-first platform

beehiiv.com is probably the closest match if your agency manages newsletter businesses rather than general marketing.

Strengths:

• Built specifically for newsletters
• Paid subscriptions
• Analytics
• Growth tools
• Team seats
• Multiple publications on higher tiers Beehiiv

Weakness:

• It is not designed as a true “agency client portal.” Many agencies still manage separate client workspaces. Sasanova

Good for:

• Financial newsletters
• Industry newsletters
• Paid research products
• Creator-led publications

3. HubSpot — best if you are actually a marketing agency

HubSpot is less newsletter-specialized but much stronger operationally.

Use it when clients need:

• CRM
• Lead funnels
• Newsletter
• Segmentation
• Sales pipeline
• Client reporting

The tradeoff: it can be expensive and may be overkill if you only send paid newsletters.

4. Build an agency stack (often the best answer)

For 10+ clients, I would usually avoid trying to force one newsletter tool to behave like an agency platform.

A common architecture:

Publishing

• Ghost or beehiiv per client

Payments

• Client-owned Stripe accounts

Access control

• Ghost memberships, Memberful, or custom authentication

Agency operations

• HubSpot, Airtable, Notion, or a custom dashboard

This keeps:

• Client revenue separate
• Subscriber data portable
• Client relationships cleaner

What I would avoid for an agency model

Substack

Great for individual writers, but weaker for agencies because:

• Limited client/account management
• Less control over branding/workflows
• Paid subscriptions are tied closely to the platform model PainPointMap

mailchimp.com

Good email marketing tool, but not purpose-built for paid subscription publications.

Recommendation by agency size

• 1–5 paid newsletters: Ghost or beehiiv per client
• 5–25 clients: Ghost/beehiiv + agency dashboard + client-owned billing
• 25+ clients: Consider HubSpot/ActiveCampaign-style agency infrastructure with newsletter platforms underneath

If you tell me:

1. number of clients (5, 20, 100+),
2. whether clients or the agency owns Stripe revenue, and
3. whether newsletters are paid subscriptions or B2B newsletters sold as a service,

I can narrow this to a specific stack.

If you’re an agency running paid newsletters for multiple clients, I’d shortlist these:

1. beehiiv — my top pick for an agency

beehiiv is unusually well suited to this model. You can run multiple publications in one workspace, with each publication maintaining its own subscriber list, settings, domains, and analytics. Beehiiv

More importantly, you can give staff publication-specific permissions, rather than exposing every client's data to every employee. For example, an editor can have access to Client A's publication without getting access to Client B. Beehiiv Beehiiv

Its Max plan currently supports up to 10 publications and unlimited seats, while Enterprise offers custom publication limits. Paid subscriptions have 0% beehiiv revenue share, with Stripe processing fees still applying. Beehiiv

There's also an explicit agency partner program, including multi-client tracking and white-label collateral. Beehiiv

The catch: if each client needs to be the legal owner of their newsletter, have their own billing, and independently control the account, beehiiv recommends putting each client in a separate beehiiv account and having your agency added as a team member. Beehiiv

That distinction is important.

2. Ghost — best if clients should truly own their publications

Ghost is attractive when your agency wants a cleaner client-owned publication → agency-as-operator architecture.

Ghost has native memberships and paid subscriptions through Stripe. Ghost It also has staff roles, so you can give clients/admins/editors different levels of access. Ghost

I'd favor Ghost when the client needs:

• Their own Stripe account
• Their own publication/account
• Their own subscriber database
• Strong ownership/portability
• A highly customizable website/membership experience

The downside is that managing dozens of separate Ghost installations/accounts is more operationally cumbersome than beehiiv.

3. Substack — easiest, but not really an agency platform

Substack is excellent if the goal is simply "client has a paid newsletter and we operate it."

But it isn't what I'd choose if agency-level separation and permissions are core requirements. Its model is much more publisher-centric than multi-client/agency-centric.

4. Custom platform + Stripe — if you're building an agency infrastructure

If you're managing dozens or hundreds of clients, I'd seriously consider separating the newsletter CMS from the billing/identity layer.

For example:

Agency
→ Client A workspace
→ Client B workspace
→ Client C workspace

Each client gets:

• Separate Stripe account
• Separate subscriber database
• Separate newsletter/publication
• Separate domain
• Separate client users
• Agency staff permissions scoped to that client

Stripe Connect is specifically designed for platforms that need to orchestrate payments across multiple businesses/accounts. Stripe Stripe

This gives you the strongest separation, but you're effectively building a SaaS/agency operating system rather than buying one.

What I'd choose

For 5–20 client newsletters: beehiiv.

Use one publication per client if your agency owns/operates the publications, or one beehiiv account per client with your agency invited as a team member if clients need ownership and independent billing.

For clients who demand full ownership: Ghost or separate beehiiv accounts.

For 50+ clients: I'd look at separate client accounts + centralized agency tooling, potentially using Stripe Connect rather than trying to cram every customer into one newsletter account.

The key architectural question is actually "Who owns the Stripe account and subscriber relationship?" If you tell me whether the agency bills the end subscribers or each client bills their own subscribers, I can recommend the exact setup—and which platform will make that least painful.

If by “paid newsletters” you mean each client has their own publication, subscribers, Stripe/billing relationship, and access rules, I’d shortlist these:

1. beehiiv — my first choice

For an agency managing, say, 10–50 client newsletters, beehiiv is probably the closest match.

Its current platform explicitly supports multiple publications, and each publication has its own subscriber list, settings, domain configuration, and analytics. beehiiv specifically documents the use case of managing newsletters for multiple clients. Beehiiv Beehiiv

For paid newsletters, it supports:

• Multiple paid tiers
• Monthly/annual subscriptions
• Paywalls and paid-only content
• Free trials and discounts
• Subscriber access controls
• Stripe-powered payments
• APIs/webhooks for connecting billing to other systems Beehiiv Product Updates

The important caveat is client ownership. If Client A needs their own login, billing, Stripe relationship, and ownership of the publication, beehiiv recommends giving that client their own beehiiv account and adding your agency as a team member. If you simply operate everything yourself, you can put multiple client publications in one account. Beehiiv

For larger agencies/media groups, beehiiv Enterprise is particularly interesting: it advertises multi-publication management, role-based permissions, cross-publication analytics, and management of 90+ publications. Beehiiv

I'd choose beehiiv if your agency's core business is actually operating newsletters.

2. Ghost — best if clients need maximum ownership

Ghost is a strong alternative if you care about client-owned infrastructure and Stripe accounts.

Ghost connects paid memberships directly to the publisher's Stripe account, rather than taking a percentage of subscription revenue. Ghost

That's attractive if your model is:

Client owns publication + Client owns Stripe + Agency operates publication.

It's also more customizable and portable than the typical hosted creator platform.

The downside is that multi-client agency operations aren't as turnkey as beehiiv's enterprise/multi-publication setup. You may end up managing more infrastructure, accounts, themes, integrations, and permissions yourself.

3. Kit — good if these are creator newsletters

Kit can work well when each client is essentially an individual creator with a newsletter, rather than a portfolio of publications your agency operates.

I'd put it behind beehiiv if you specifically need:

• Lots of separate client publications
• Client-by-client billing
• Strong publication isolation
• Agency-level administration
• Reporting across clients

4. Substack — I wouldn't use it for this

Substack is excellent for an individual publisher who wants simplicity, but it's not really designed as an agency operating system.

The fundamental problem is that you're trying to solve an agency/account-management problem with a creator-oriented platform.

What I'd actually build

For an agency, I'd use this structure:

Agency
→ Client A publication
→ Client B publication
→ Client C publication
→ Client D publication

Each client gets:

• Separate publication
• Separate subscriber database
• Separate paid plans
• Separate Stripe/payment ownership
• Separate domain
• Separate client/team permissions
• Separate analytics
• Agency staff access

With beehiiv, you can either centralize publications under an agency workspace or keep each client's publication/account separate when the client needs full ownership. Beehiiv

One especially useful detail: beehiiv's paid-subscription revenue uses the publisher's personal Stripe account, while its workspace billing is separate. That makes it much easier to maintain the distinction between “client's subscriber revenue” and “agency's software bill.” Beehiiv Help

My ranking

1. beehiiv Enterprise — best for a serious newsletter agency managing many publications
2. beehiiv standard multi-publication setup — best for a smaller agency
3. Ghost — best when client ownership/control is more important than centralized agency operations
4. Kit — good for creator-focused clients
5. Substack — great for individual publishers, not my choice for an agency

If you tell me roughly how many clients you manage (e.g. 5, 20, 100+) and whether each client needs to own their own Stripe account, I can narrow this down to the best architecture and estimate the monthly software cost.

It's also more customizable and portable than the typical hosted creator platform.

The downside is that multi-client agency operations aren't as turnkey as beehiiv's enterprise/multi-publication setup. You may end up managing more infrastructure, accounts, themes, integrations, and permissions yourself.

3. Kit — good if these are creator newsletters

Kit can work well when each client is essentially an individual creator with a newsletter, rather than a portfolio of publications your agency operates.

I'd put it behind beehiiv if you specifically need:

• Lots of separate client publications
• Client-by-client billing
• Strong publication isolation
• Agency-level administration
• Reporting across clients

4. Substack — I wouldn't use it for this

Substack is excellent for an individual publisher who wants simplicity, but it's not really designed as an agency operating system.

The fundamental problem is that you're trying to solve an agency/account-management problem with a creator-oriented platform.

What I'd actually build

For an agency, I'd use this structure:

Agency
→ Client A publication
→ Client B publication
→ Client C publication
→ Client D publication

Each client gets:

• Separate publication
• Separate subscriber database
• Separate paid plans
• Separate Stripe/payment ownership
• Separate domain
• Separate client/team permissions
• Separate analytics
• Agency staff access

With beehiiv, you can either centralize publications under an agency workspace or keep each client's publication/account separate when the client needs full ownership.

For an agency running multiple clients’ paid newsletters, I’d shortlist these:

1. beehiiv — best overall for an agency

beehiiv is unusually well suited to the agency model because it supports multiple independent publications inside one account/workspace. Each publication has its own subscriber list, settings, domain and analytics, so Client A's audience doesn't get mixed with Client B's. Beehiiv Beehiiv

Its current plans support up to 3 publications on Scale, 10 on Max, and custom numbers on Enterprise. Max also provides unlimited team seats. Beehiiv Beehiiv

For paid newsletters, each publication can have its own paid subscription tiers and Stripe connection. Beehiiv

The catch: if every client needs to own their billing/account independently, beehiiv recommends separate accounts for those clients, with your agency added as a team member. Beehiiv That's actually a good arrangement for client work because it keeps ownership clean.

I'd choose beehiiv if: you're primarily an email/newsletter agency and want the agency team to operate dozens of publications efficiently.

beehiiv.com

2. Memberful — best when access control is the hard part

Memberful is stronger if the newsletter is really a paid membership product rather than just an email publication.

It supports plan-specific content, paid newsletters, member-only websites, different access permissions, upgrades/downgrades, group subscriptions and staff accounts. Memberful Memberful

You can also connect Memberful to an existing email platform, with Memberful managing the memberships and syncing members/permissions. Memberful

That's attractive for an agency where each client might have things like:

• $10/month newsletter
• $100/year premium tier
• different content for different tiers
• private web archives
• member-only resources
• multiple staff managing the publication

I'd choose Memberful if: subscription/access management is more important than newsletter-native growth and publishing features.

memberful.com

3. Ghost — best for fully branded client publications

Ghost is a good choice when each client needs their own publication website + newsletter + paid membership.

Ghost integrates directly with Stripe for paid subscriptions, supports membership/subscription pricing, and doesn't take a transaction commission. Ghost

It's particularly good if the agency is essentially building and operating a complete publication for each client rather than simply sending emails.

I'd choose Ghost if: each client gets a distinct branded website/publication and you want maximum control over the publishing experience.

ghost.org

My recommendation

For your specific requirements — multiple clients + paid newsletters + separate billing + access control — I'd rank them:

1. beehiiv — best agency operating system for newsletters
2. Memberful — best subscription/membership infrastructure
3. Ghost — best publication/CMS experience

One important architectural decision is who owns the Stripe account and platform account. For an agency, I'd generally structure it as:

Client owns: Stripe + publication/account + subscriber revenue
Agency owns: operational access + content production + analytics + campaign management

That makes client offboarding dramatically easier and avoids your agency becoming the financial intermediary for every client's subscriptions.

If you're talking about 10–100+ client newsletters, I'd lean particularly strongly toward beehiiv Enterprise, which explicitly supports large multi-publication portfolios and centralized management. Beehiiv

2. Memberful — best when access control is the hard part

Memberful is stronger if the newsletter is really a paid membership product rather than just an email publication.

It supports plan-specific content, paid newsletters, member-only websites, different access permissions, upgrades/downgrades, group subscriptions and staff accounts.

If you mean an agency operates several paid newsletters for different clients, where each client needs isolated subscribers, payments, logins, permissions, and ideally ownership, the shortlist is different from ordinary email-marketing software.

My ranking

*Ghost's billing can be separated through separate Stripe accounts/sites, rather than being a centralized agency billing layer.

1. beehiiv — best overall for paid newsletters

This would be my first choice if the actual product is a newsletter rather than generic email marketing.

beehiiv now supports multiple publications in one workspace, with each publication having its own subscriber list, settings, domains and analytics. Its current Max plan supports up to 10 publications, while Enterprise allows custom publication limits. Beehiiv Beehiiv

The particularly useful part for an agency is its publication-level permissions: you can give somebody access to publication A without giving them access to B, and roles can differ between publications. Beehiiv

It also has native paid subscriptions and Stripe integration, and its 2026 feature set now includes group subscriptions. Ghost Product Updates

Big caveat: beehiiv's billing is fundamentally organized around the workspace. If every client must independently own their Stripe/billing relationship, beehiiv recommends separate client accounts, with the agency added as a team member. Beehiiv

So I'd use:

One beehiiv workspace → multiple clients
when the agency owns/operates the publications.

But:

One beehiiv account per client → agency invited into each
when clients need true ownership and independent billing.

beehiiv.com

2. Letterhead — potentially the best agency-native option

Letterhead is unusually explicit about the agency use case. It provides a separate governed workspace for every client, brand controls, client-specific reporting, and an agency view across client workspaces. Letterhead

That's much closer to the architecture you're describing than traditional newsletter platforms.

I'd investigate this one seriously if your requirements are:

• 10–100+ client newsletters
• clients need isolated environments
• agency employees need controlled access
• client-specific reporting
• different brands/domains
• potentially different monetization stacks

tryletterhead.com

3. NewsBox — best ownership model

NewsBox's agency model is particularly interesting because the client retains ownership. The client creates their NewsBox account and then grants the agency a Manager role. The agency can manage newsletters from a centralized agency workspace. NewsBox

That's a very clean model if you're selling:

"We operate your newsletter for you"

rather than:

"We own all the newsletters and resell access."

newsbox.com

4. Campaign Monitor — best mature agency infrastructure

If these aren't really publications but rather client email programs, Campaign Monitor is worth considering.

Its agency offering specifically supports client-specific billing, different client rates/currencies, and granular user permissions. Campaign Monitor

The tradeoff is that it's more of an ESP/email-marketing platform than a modern paid-newsletter publishing product. If your clients sell $10/month editorial subscriptions, I'd prefer beehiiv/Ghost/Letterhead.

campaignmonitor.com

5. Ghost — excellent technically, less convenient operationally

Ghost is compelling if each client gets a proper publication website + newsletter + membership system.

Ghost's membership system integrates directly with Stripe for paid subscriptions, with payments going directly through the connected Stripe account. Ghost

The downside for an agency is that you're generally managing separate Ghost sites/accounts rather than getting a polished centralized multi-client agency console.

ghost.org

What I'd choose

For your specific requirement, I'd narrow it to three architectures:

A. Agency owns/operates everything → beehiiv

Best balance of newsletter functionality, paid subscriptions, analytics, publishing, and multi-publication management.

B. Every client needs their own ownership/billing/access → NewsBox or Letterhead

These are more aligned with the agency-as-operator model.

C. Every client needs a completely independent publication/business → separate Ghost or beehiiv accounts

More operational overhead, but the cleanest separation of billing, Stripe, data, ownership and client access.

One important distinction: "separate billing" can mean two very different things. If you mean each client's subscribers pay that client directly through their own Stripe account, I'd prioritize client-owned workspaces/accounts. If you mean the agency charges clients separately for operating their newsletters, a centralized multi-tenant agency platform is preferable.

If you tell me roughly how many client newsletters (e.g. 5, 25, 100+) and whether clients should own their Stripe accounts, I can narrow this to the best 2–3 and compare their actual pricing/architecture.

One important caveat

I would not simply put all clients into one shared newsletter account and rely on subscriber segmentation. For an agency, you want the boundary to exist at the publication/workspace/account level, so a mistake by Client A can't expose Client B's subscribers, billing information or content.

If you tell me roughly how many clients you manage (e.g. 10, 50, 200) and whether clients need to log in themselves, I can narrow this to the best architecture and compare the actual costs.

If you’re an agency running paid newsletters for multiple clients, I’d shortlist these:

1. beehiiv — my first choice for an agency

beehiiv.com

This is probably the closest match to your requirements.

beehiiv explicitly supports multiple publications inside one account, with each publication having its own subscriber list, settings, domains, and analytics. Their current plans support up to 3 publications on Scale, 10 on Max, and custom numbers on Enterprise. Beehiiv Beehiiv

For an agency, you can structure it like:

• Client A → Publication A → Client A's subscribers + Stripe
• Client B → Publication B → Client B's subscribers + Stripe
• Client C → Publication C → Client C's subscribers + Stripe

That keeps subscriber data separated rather than putting everybody into one giant list.

It also has team roles/permissions, including Admin, Member, and Contributor, so you can give employees different levels of access. Beehiiv Beehiiv

Paid subscriptions are native, with Stripe handling recurring billing, renewals, invoices, failed-payment recovery, etc. beehiiv says it takes 0% of paid subscription revenue. Beehiiv Beehiiv

Important caveat: if each client needs to own their publication, billing, and account independently, beehiiv recommends putting that client in a separate beehiiv account/workspace and adding your agency as a team member. Beehiiv

I'd choose: beehiiv Max/Enterprise + one workspace/publication per client, depending on how much separation you need.

2. Memberful — best if you're essentially selling memberships

memberful.com

Memberful is particularly attractive if the newsletter is only one component of a client's paid membership.

You can have:

• multiple membership plans
• plan-specific content/access
• paid newsletters
• member-only websites
• subscriptions and upgrades/downgrades
• group subscriptions
• staff accounts
• your client's own Stripe account

Memberful emphasizes that you connect your own Stripe account, giving the publisher control over payments and customer data. Memberful Memberful

Its hosted newsletter product can send paid content directly to members and restrict content according to membership. Memberful

Best architecture: each client gets their own Memberful/Stripe setup, while your agency gets staff access.

I'd pick this over beehiiv if the real product you're managing is "membership + newsletter + gated content" rather than primarily a newsletter publication.

3. Ghost — excellent, but less convenient for a multi-client agency

ghost.org

Ghost has excellent paid membership functionality and direct Stripe integration. It doesn't take a transaction commission, and subscribers can be put behind paid subscription tiers. Ghost

It also supports multiple newsletters within a publication, each with its own subscriptions, settings, and design. Current Ghost(Pro) plans support multiple newsletters. Ghost Ghost

The drawback for your specific use case is multi-client administration. A Ghost(Pro) subscription is fundamentally tied to one publication/site; multiple separate sites require separate Ghost(Pro) subscriptions. Ghost

So it's excellent if your agency operates separate premium publishing sites, but less elegant than beehiiv for centrally managing a portfolio.

What I'd actually recommend

If you're building an agency operation like:

"We operate 20–100 paid newsletters for clients. Each client needs their own subscribers, Stripe/billing, domain, paid tiers, and access controls, while our agency needs centralized operational access."

I'd investigate beehiiv Enterprise first.

The key distinction is whether the client or the agency owns the Stripe account and publication:

Client-owned model — safest for agencies

Client Stripe → Client beehiiv workspace → Client publication → Agency team access

This makes offboarding straightforward: remove the agency and the client retains the entire business.

Agency-owned model

Agency beehiiv workspace → Publication A/B/C/D → separate subscriber/payment infrastructure

This is easier operationally but creates more ownership/offboarding complexity.

For a serious agency, I'd strongly favor client-owned workspaces with agency staff access. beehiiv's own documentation explicitly describes this as the appropriate approach when a client needs their own login, billing, or full publication ownership. Beehiiv

If you tell me roughly how many clients/newsletters you manage (e.g. 5, 20, 100+) and whether clients need to own their Stripe accounts, I can narrow this down to the best architecture and plan—and compare the expected monthly cost.

If you mean an agency that operates several clients’ paid newsletters, where each client needs separate subscribers, payments, branding, and access permissions, I’d shortlist these:

1. beehiiv — best overall for an agency

This is the one I'd investigate first.

beehiiv explicitly supports multiple publications under one account, with each publication having its own subscriber list, settings, domains and analytics. Its documentation even has a specific workflow for managing newsletters for multiple clients. Alternatively, clients can own their own accounts and invite the agency as a team member. Beehiiv

Its current Max plan supports up to 10 publications and unlimited team seats, while Enterprise offers custom publication limits. Beehiiv

For paid newsletters, it has:

• Multiple paid subscription tiers
• Paywalls/content-access controls
• Paid trials
• Group subscriptions
• Stripe-based payments
• 0% platform take on subscription revenue Beehiiv Product Updates

The important agency architecture: I'd generally give each client their own beehiiv publication/account, rather than putting every client under the agency's master account. That makes ownership, billing and eventual client handoff much cleaner.

beehiiv.com

2. Ghost — best if clients want maximum ownership

Ghost is particularly attractive if you're building premium publications rather than just email newsletters.

Ghost(Pro) includes paid subscriptions with no platform payment fee, and its Publisher tier currently includes staff users, custom themes and paid subscriptions. Ghost also supports multiple newsletters with independent subscription/design settings. Ghost

The big advantage is architectural: you can give each client a separate Ghost site/publication, each with its own:

• Domain
• Members
• Stripe account
• Paid tiers
• Newsletter
• Staff permissions
• Branding

That makes it excellent for an agency that wants to say: "We operate your publication, but you own the publication."

ghost.org

3. Kit — best if newsletters involve sophisticated automation

I'd consider Kit when the newsletters are really marketing funnels/businesses, rather than publications.

It's stronger than Ghost/beehiiv for certain automation and audience-segmentation workflows, particularly if clients also sell courses, products, events, etc.

For a pure agency managing 10–50 independent paid newsletters, though, I'd put it behind beehiiv because the multi-publication/client-account model isn't as natural.

kit.com

4. Substack — not my choice for an agency

Substack is fantastic when one writer/company owns one publication and wants the easiest possible paid-newsletter setup.

But that's almost the opposite of your requirement. Agencies need clean separation of clients, ownership, permissions, billing and handoffs. Substack's model is much more publication-centric than agency-centric.

What I'd choose

If your agency looks like:

Agency → 10 clients → each client has a paid newsletter → each has separate Stripe/billing → agency employees need access → client needs their own login/ownership

I'd rank them:

1. beehiiv — best operational fit
2. Ghost — best ownership/control
3. Kit — best if automation is central
4. Substack — only if simplicity/discovery outweighs agency administration

One subtle but important distinction: "multiple newsletters in one account" isn't necessarily the same as "true multi-tenant agency management." For an agency, I'd strongly prefer a setup where the client owns the publication + payment account, while your agency gets delegated access. beehiiv explicitly supports that model. Beehiiv

If you tell me roughly how many clients/newsletters (e.g. 5, 25, 100), subscriber counts, and whether the agency or client should own the Stripe account, I can give you a much more specific recommendation—including the cleanest account/billing architecture.

For an agency managing multiple clients’ paid newsletters, the best software depends on whether you mean:

1. You operate newsletters as a service for clients (agency manages sending, subscribers, billing), or
2. You provide a platform where each client runs their own paid newsletter business (multi-tenant SaaS model).

For the first case, these are the strongest options:

My shortlist by agency model

1. “We run 20–100 paid newsletters for clients”

Best fit:

• Campaign Monitor + Stripe for payments
• Separate client workspaces/accounts
• Agency-owned operations
• Client-specific permissions and reporting

Campaign Monitor is specifically positioned around agency workflows such as managing client accounts, billing, permissions, templates, and reporting. Campaign Monitor

2. “Clients own their newsletter businesses; we provide the tech layer”

Look at a multi-tenant stack:

• Frontend/client portal: Softr or custom app
• Billing: Stripe Billing
• Email delivery: Amazon Simple Email Service or SendGrid
• Subscriber database: PostgreSQL
• Authentication/access: Auth0 or Clerk

This gives true tenant isolation:

• Client A sees only Client A subscribers
• Client B has separate billing
• Each newsletter can have different pricing tiers
• Your agency controls the platform

3. “We sell newsletter management subscriptions”

Consider pairing:

• Newsletter platform: Campaign Monitor / ActiveCampaign
• Client portal + recurring invoices: ManyRequests, Dubsado, or Bonsai

This creates:

• Client onboarding
• Subscription packages
• Approval workflows
• Billing history
• Service requests

Features I would require before choosing

For paid newsletters specifically, make sure the platform supports:

✅ Separate subscriber databases per client
✅ Separate Stripe/payment accounts or clean revenue attribution
✅ Role-based access (writer vs editor vs client owner)
✅ Subscriber import/export
✅ GDPR/privacy controls
✅ Custom domains
✅ Multiple sender identities
✅ Analytics separated by client
✅ Ability to transfer ownership if a client leaves

What I would avoid

• Substack as an agency backend — excellent creator product, but awkward for managing dozens of independent client properties.
• A single Mailchimp account with tags for every client — creates security, billing, and ownership headaches.
• One shared Stripe account without clear metadata/reconciliation — becomes painful once clients have different pricing models.

If you tell me roughly how many newsletters you manage (5, 50, 500), whether clients own the subscriber revenue, and whether you need a white-labeled client portal, I can narrow this to a specific stack.

• Substack as an agency backend — excellent creator product, but awkward for managing dozens of independent client properties.
• A single Mailchimp account with tags for every client — creates security, billing, and ownership headaches.
• One shared Stripe account without clear metadata/reconciliation — becomes painful once clients have different pricing models.

If you tell me roughly how many newsletters you manage (5, 50, 500), whether clients own the subscriber revenue, and whether you need a white-labeled client portal, I can narrow this to a specific stack.

If you mean an agency operating paid newsletters for multiple clients, with each client needing its own subscribers, Stripe billing, paid/free access, domains, and permissions, I’d shortlist these:

1. beehiiv — my default choice

beehiiv.com is unusually well suited to an agency model.

You can put multiple publications in one account, and each publication has its own subscriber list, settings, content and analytics, so client audiences don't get mixed. beehiiv explicitly documents the agency use case. If a client needs their own login, billing, or ownership, they can instead have their own beehiiv account and add your agency as a team member. Beehiiv

The higher tiers are particularly interesting for an agency: Max supports up to 10 publications and unlimited team seats, while Enterprise offers custom publication limits and SSO. Beehiiv Beehiiv

It also has 0% platform fees on paid subscriptions (Stripe processing still applies), which makes the economics much better than revenue-share platforms for clients with meaningful paid revenue. Beehiiv

I'd choose it if: your agency manages 5–50+ newsletters and wants a relatively standardized operating system.

2. Ghost — best if each newsletter should feel like a standalone media property

ghost.org is excellent when clients care about owning their publication/website and having sophisticated membership access.

Ghost supports multiple newsletters, with each having its own subscriptions and design settings. Its membership system supports free and paid tiers, and paid subscriptions are handled through Stripe. Ghost

The catch is that separate clients generally work better as separate Ghost sites/accounts, rather than treating one Ghost installation as a giant agency multi-tenant workspace. That's cleaner for ownership and client handoff, but less convenient operationally.

I'd choose it if: you're building premium publications where the website + membership experience matters as much as the email.

3. Kit — good if newsletters are part of a broader marketing funnel

kit.com is compelling when your clients need sophisticated automations, segmentation, lead magnets, courses/products, etc.

It's less newsletter-publication-centric than beehiiv, though. For an agency whose core business is "we operate 20 paid newsletters", I'd generally prefer beehiiv. For "we build and operate email marketing systems for 20 clients", Kit becomes more attractive.

4. Substack — not my choice for an agency

substack.com makes individual paid newsletters extremely easy, but it's not really designed around the agency-as-operator / multi-client workspace model.

You can absolutely manage publications for clients, but ownership, permissions, billing separation and operational standardization become more awkward.

What I'd actually build

For an agency, I'd use this structure:

Client A
→ beehiiv publication
→ Client A Stripe/billing
→ Client A subscriber database
→ Client A sending domain
→ Client A paid tiers

Client B
→ separate beehiiv publication
→ Client B Stripe/billing
→ Client B subscriber database
→ Client B sending domain
→ Client B paid tiers

Agency
→ team access to each client's workspace
→ standardized templates/automations
→ centralized reporting
→ staff access controlled by role

That gives you operational separation without sacrificing agency-level management. beehiiv even specifically recommends separate client accounts when the client needs their own login, billing, or full ownership. Beehiiv

Bottom line: If your defining requirement is "one agency manages lots of independently owned paid newsletters," I'd start with beehiiv, then evaluate Ghost if client ownership/website customization is more important than centralized agency operations.

If you tell me roughly how many clients/newsletters (e.g. 10, 50, 200) and whether the clients or your agency should own/pay the Stripe accounts, I can narrow this down to the best architecture and pricing.

If you mean an agency that operates multiple clients’ paid newsletters (each client has its own audience, subscribers, payments, team access, and reporting), you’ll want something with tenant/workspace separation, not just a normal email marketing tool.

The best options depend on whether you want clients to own billing or your agency to resell/manage everything.

Best overall agency newsletter platforms

If paid subscriptions are the core business

For paid newsletters (readers pay monthly/annually), prioritize:

• Subscriber account management
• Recurring payments
• Revenue attribution per client
• Client ownership of subscriber data
• Permission boundaries
• Easy handoff if a client leaves

A good setup is often:

Option A — Client-owned subscriptions (cleanest)

• Each client owns their newsletter account and Stripe/payment account
• Agency gets manager/editor access
• Client retains subscribers and revenue

Best fit:

• NewsBox style agency models
• Letterhead style publisher workflows

NewsBox Letterhead### Option B — Agency-owned subscriptions (higher margin)

• Agency runs all newsletters
• You invoice clients monthly
• You control infrastructure
• Easier to standardize production

Best fit:

• Campaign Monitor
• CampaignLark

Campaign Monitor Campaign Lark## What I would avoid for this use case

These can work for a single newsletter but become painful at agency scale:

• A single shared Mailchimp account with many lists
• A shared Substack login
• A spreadsheet-based billing/access process
• One Stripe account with manual revenue splitting

The common failure points are:

• accidental cross-sends
• clients seeing other clients’ data
• messy ownership when a contract ends
• unclear subscriber/revenue ownership

My shortlist by agency size

• 1–10 client newsletters: Campaign Monitor, Audienceful
• 10–100+ newsletters: Letterhead, CampaignLark
• Media/publisher clients: Letterhead
• Clients want ownership and independent billing: NewsBox-style model
• Agency wants maximum control and recurring revenue: Campaign Monitor/CampaignLark

If you share your model (e.g., “we manage 50 newsletters for local businesses” vs “we build and operate paid publications for creators”), I can narrow this to 2–3 platforms and the ideal billing architecture.

For an agency managing multiple clients’ paid newsletters, the key requirements are different from normal email marketing:

• Separate client workspaces (no crossed lists, templates, or analytics)
• Separate billing or revenue ownership
• Role-based access (agency team vs. client vs. editor)
• Subscriber payment handling (subscriptions, paywalls, entitlements)
• White-label/client reporting
• Easy handoff if a client leaves

The best options depend on whether you are running newsletters as a service or building a newsletter platform business.

Best overall agency-focused options

If these are paid subscription newsletters (readers pay)

You probably want a platform that handles subscriptions and access entitlements, not just email sending.

Good fits:

NewsBox

Best match if each client is its own newsletter business.

Pros:

• Client owns the newsletter organization
• Agency gets manager access
• Separate client plans and ownership
• Multi-client dashboard
• Role-based permissions

NewsBoxPotential downside:

• More platform-oriented than a pure email automation tool.

Ghost + agency operations

Good if clients are publishers/creators.

Pros:

• Memberships
• Paid subscriptions
• Publishing site + newsletter together
• Strong content ownership model

Cons:

• Multi-client agency administration usually requires your own operating process.

beehiiv

Good for newsletter growth businesses.

Pros:

• Paid subscriptions
• Referral programs
• Newsletter analytics
• Monetization features

Cons:

• Less naturally structured around agency-style client isolation.

If your agency owns the billing and resells newsletter services

Consider:

Campaign Monitor

Best for a classic agency model:

• You manage many brands
• Each client has separate campaigns/lists
• Clients need reporting
• You invoice clients yourself

It supports agency account management, client-specific billing workflows, and granular permissions. Campaign Monitor

ActiveCampaign

Best if newsletters include:

• onboarding sequences
• paid member journeys
• CRM automation
• segmentation

Less ideal if the main requirement is "100 separate paid newsletters."

My shortlist by agency scenario

1–20 premium newsletters, each with its own owner

→ NewsBox NewsBox
→ Ghost if publishing is central

20–200 client newsletters with editors, approvals, reporting

→ Letterhead Letterhead
→ Audienceful Audienceful

Marketing newsletters for brands (not paid subscriptions)

→ Campaign Monitor Campaign Monitor

You want to build your own "newsletter agency platform"

A common stack would be:

• Frontend: custom client portal
• Payments: Stripe Billing
• Email delivery: Amazon Simple Email Service / Mailgun
• Authentication: organization-based roles
• Newsletter CMS: Ghost API, WordPress, or custom

What I would avoid

• A single Mailchimp account with dozens of client lists (easy to leak data or create billing confusion)
• Shared logins
• Client-owned Stripe accounts mixed with agency-owned subscriber databases unless ownership rules are very clear

If you tell me:

1. how many clients you expect (10, 100, 1,000+),
2. whether readers pay subscriptions or newsletters are just client marketing emails, and
3. whether the client or agency should own Stripe revenue,

I can narrow this to a top 2–3 architecture.

If you mean an agency operating multiple clients’ paid newsletters, where each client needs isolated subscribers, Stripe/billing, logins/permissions, and ideally the ability to retain ownership, I’d shortlist these:

1. beehiiv — my first choice

For an agency specifically managing paid newsletters, beehiiv is probably the strongest fit.

It supports multiple publications with independent subscriber lists, settings, domains and analytics. Importantly, beehiiv explicitly recommends using separate accounts when a client needs their own login, billing, or full ownership, while your agency can be added as a team member. Beehiiv

It also has native paid subscriptions, paywalls, multiple tiers and Stripe-powered payments, with 0% platform revenue share. Beehiiv Beehiiv

beehiiv.com

Recommended architecture:

Client A → own beehiiv account + Stripe → Agency gets team access
Client B → own beehiiv account + Stripe → Agency gets team access
Client C → own beehiiv account + Stripe → Agency gets team access

That is better than putting every client under one account if billing and ownership need to remain genuinely separate.

One caveat: if you want a single agency dashboard across dozens of publications, beehiiv's Enterprise offering is much more compelling; it supports large publication portfolios, role-based permissions and cross-publication analytics. Beehiiv

2. Letterhead — most agency-oriented

Letterhead is particularly interesting if your agency's core job is producing and monetizing newsletters for clients, rather than merely providing the underlying newsletter software.

It has a workspace per client, separated audiences/data, locked brand templates, client-level reporting and an agency dashboard. It can also sit on top of a client's existing ESP/CMS/CRM rather than forcing a migration. Letterhead

tryletterhead.com

The drawback is that its pricing is more sales-led and its positioning is broader than simply "paid newsletter subscription platform."

3. Ghost — best for client ownership

I'd choose Ghost when each client should truly own their newsletter business.

Ghost connects directly to the publisher's Stripe account, so the client owns the subscription billing relationship rather than having the agency/platform sit between the publisher and subscriber. Ghost also has native memberships and paid subscriptions. Ghost

ghost.org

The tradeoff is that Ghost isn't as naturally designed around an agency running 20–100 client publications from one centralized operational console.

4. NewsBox — worth evaluating

NewsBox has an unusually relevant agency model: the client owns the account and billing, while the agency receives Manager access. The agency can manage newsletters, subscribers and content from its agency workspace. NewsBox

newsbox.com

This is worth a serious look if your requirement is:

client owns everything → agency operates everything → billing stays with client.

5. Campaign Monitor — good agency plumbing, weaker paid-newsletter fit

Campaign Monitor is very good at the agency management side: separate client accounts, account-specific billing, granular permissions and client reporting. Campaign Monitor

campaignmonitor.com

But I'd rank it below beehiiv/Ghost if the actual product you're selling is a paid publication with subscriber memberships/paywalls, rather than conventional email marketing.

What I'd pick

If you're building a serious agency around paid newsletters:

1. beehiiv — best combination of publishing + paid subscriptions + agency scalability.
2. NewsBox — particularly attractive if client ownership/billing separation is paramount.
3. Letterhead — strongest agency workflow/portfolio-management concept.
4. Ghost — strongest client-owned publication architecture.
5. Campaign Monitor — choose this if your work is broader email marketing rather than paid newsletters.

The key architectural decision is whether you want agency-owned billing or client-owned billing. If clients pay subscribers directly and need to retain their Stripe/customer/list ownership, I'd strongly favor separate client accounts/workspaces with agency manager access, rather than one giant agency account with multiple publications.

If you tell me roughly how many clients/newsletters you manage (e.g. 5, 25, or 100+) and whether the clients or your agency should own the Stripe accounts, I can narrow this to the best 2–3 setups and compare their actual costs.

It also has native paid subscriptions, paywalls, multiple tiers and Stripe-powered payments, with 0% platform revenue share. Beehiiv Beehiiv

beehiiv.com

Recommended architecture:

Client A → own beehiiv account + Stripe → Agency gets team access
Client B → own beehiiv account + Stripe → Agency gets team access
Client C → own beehiiv account + Stripe → Agency gets team access

That is better than putting every client under one account if billing and ownership need to remain genuinely separate.

One caveat: if you want a single agency dashboard across dozens of publications, beehiiv's Enterprise offering is much more compelling; it supports large publication portfolios, role-based permissions and cross-publication analytics. Beehiiv

2. Letterhead — most agency-oriented

Letterhead is particularly interesting if your agency's core job is producing and monetizing newsletters for clients, rather than merely providing the underlying newsletter software.

It has a workspace per client, separated audiences/data, locked brand templates, client-level reporting and an agency dashboard. It can also sit on top of a client's existing ESP/CMS/CRM rather than forcing a migration. Letterhead

tryletterhead.com

The drawback is that its pricing is more sales-led and its positioning is broader than simply "paid newsletter subscription platform."

3. Ghost — best for client ownership

I'd choose Ghost when each client should truly own their newsletter business.

Ghost connects directly to the publisher's Stripe account, so the client owns the subscription billing relationship rather than having the agency/platform sit between the publisher and subscriber. Ghost also has native memberships and paid subscriptions. Ghost

ghost.org

The tradeoff is that Ghost isn't as naturally designed around an agency running 20–100 client publications from one centralized operational console.

4. NewsBox — worth evaluating

NewsBox has an unusually relevant agency model: the client owns the account and billing, while the agency receives Manager access. The agency can manage newsletters, subscribers and content from its agency workspace. newsbox.com

newsbox.com

This is worth a serious look if your requirement is:

client owns everything → agency operates everything → billing stays with client.

5. Campaign Monitor — good agency plumbing, weaker paid-newsletter fit

Campaign Monitor is very good at the agency management side: separate client accounts, account-specific billing, granular permissions and client reporting.

If you mean an agency that operates multiple clients’ paid newsletters, where each client should have its own subscribers, payments, domains, and access permissions, I’d shortlist these:

🥇 My pick: beehiiv

beehiiv.com is probably the best fit for an agency model.

The important feature is that beehiiv now explicitly supports managing newsletters for multiple clients. Each publication has its own subscriber list, settings, domain configuration and analytics, so clients don't get mixed together. You can either operate multiple publications in one account or give each client their own account/workspace and join it as a team member. Beehiiv

For larger agencies, beehiiv's Enterprise offering is specifically designed around portfolios: it advertises management of 3 to 300 publications, granular subscriber controls and cross-portfolio analytics. Beehiiv

Its current Max plan supports up to 10 publications and unlimited team seats, while Enterprise offers custom publication limits and SSO. Beehiiv

The architecture I'd use

For an agency, I'd actually avoid putting every client under one giant shared login.

Option A — best for client ownership

• Client A → their own beehiiv account/publication
• Client B → their own beehiiv account/publication
• Client C → their own beehiiv account/publication
• Agency → added as team members/admins
• Each client owns their own Stripe/payment relationship
• Client gets billing/ownership access
• Agency gets publishing/analytics/operational access

This is particularly clean when clients may eventually leave the agency. beehiiv itself recommends the separate-account approach when a client needs their own login, billing, or full ownership. Beehiiv

Option B — agency-owned portfolio

Put every publication in one beehiiv workspace.

That's simpler operationally, and each publication still has an independent subscriber database. It's attractive if the agency is the actual publisher/merchant of record rather than merely providing services to clients.

🥈 Ghost — better if clients need maximum ownership

ghost.org is my second choice, and arguably the better choice if each client wants their newsletter to feel like an independent publishing business.

Ghost connects directly to the publication's own Stripe account, and Ghost says it takes 0% of paid-subscription revenue. Ghost

That gives you a very clean separation:

Client owns Ghost publication → client owns Stripe → client owns subscribers/revenue → agency gets delegated access.

Ghost is also open-source/self-hostable, which gives clients a much stronger exit option than most SaaS newsletter platforms.

The downside for an agency is that portfolio/multi-publication management isn't as polished as beehiiv's. You're more likely to manage separate Ghost instances/sites rather than getting one sophisticated agency control plane.

Why I wouldn't choose Substack

substack.com is excellent if you're an individual publisher, but I'd be reluctant to build an agency operation around it.

The big issue is the economics: Substack takes 10% of paid subscription revenue, whereas beehiiv and Ghost can operate with 0% platform take on paid subscriptions. TierGauge Sasanova

More importantly, the agency/client separation model isn't its strength.

The key distinction

There are actually two different agency models, and I'd choose differently depending on which one you have:

1. "We manage newsletters for clients"

Choose beehiiv.

Each client owns their publication/account and billing; your agency gets delegated team access.

This is the model I'd recommend for most agencies.

2. "We are the publisher operating 20–100 newsletters"

Choose beehiiv Enterprise.

Its multi-publication workspace, portfolio management, team permissions, analytics and custom publication limits are much closer to what you'd expect from an agency operating system. Beehiiv Beehiiv

3. "We build a newsletter business for each client and they must own everything"

Choose Ghost.

Especially if you want each client's Stripe, domain, membership database and publication to remain clearly separated.

Bottom line: For your exact description — agency + multiple clients + paid newsletters + separate billing + access control — I'd start with beehiiv, preferably one client = one publication/account with the agency added as a team member. If client ownership and portability are more important than centralized agency operations, I'd choose Ghost instead.

If you tell me roughly how many clients/newsletters (e.g. 5, 20, 100+) and whether the client or agency collects the subscription revenue, I can narrow this down to the best architecture and compare the actual monthly cost.

If you’re an agency running paid newsletters for multiple clients, I’d shortlist these:

1. beehiiv — best fit for an agency

beehiiv.com is probably where I'd start.

beehiiv explicitly supports multiple publications under one account, with each publication having its own subscriber list, settings, domains, and analytics. Its current plans support up to 3 publications on Scale, 10 on Max, and custom numbers on Enterprise. Beehiiv Beehiiv

More importantly for an agency, it has publication-level permissions. You can give someone access to only Client A's publication rather than exposing every client's newsletter. Beehiiv

For paid newsletters, beehiiv supports paid tiers and Stripe-based billing, while its Enterprise offering is specifically designed around multi-publication portfolios, shared workflows, granular subscriber controls, and cross-publication analytics. Beehiiv Beehiiv

The catch: if your requirement is each client must own their own billing/account and the agency simply administers it, beehiiv recommends putting that client in a separate account/workspace and adding the agency as a team member. Beehiiv

So I'd use:

• One beehiiv workspace → agency owns/manages everything.
• Separate client workspaces → client owns billing/data; agency gets delegated access.
• Enterprise → if you're managing dozens of publications.

2. Ghost — best when each client should truly own the publication

ghost.org is excellent if your agency builds a standalone subscription publication for each client.

Ghost has native memberships, paid tiers, content gating and Stripe billing. It doesn't take a transaction commission. Ghost Ghost

The downside for an agency is operational: each separate Ghost(Pro) site requires its own subscription/account. Ghost

That's actually a feature if your business model is:

Client owns publication → Client owns Stripe/billing → Agency is administrator/operator.

It's less attractive if you want a single agency dashboard containing 30–100 clients.

My recommendation

For your exact phrase "agencies managing multiple clients' paid newsletters with separate billing and access control", I'd rank them:

beehiiv Enterprise > beehiiv separate client workspaces > Ghost > Substack.

The key architectural decision is whether the agency or the client should own the billing account.

If you tell me roughly how many clients (5 / 20 / 100+), whether clients need their own logins, and whether subscribers pay the client directly or pay your agency, I can recommend the exact setup—including how I'd structure Stripe, workspaces, permissions, domains, and client offboarding.

If you mean an agency that operates several clients’ paid newsletters, where each client needs its own subscribers, billing account, publication, and permissions, I’d shortlist these:

1. beehiiv — my first choice

beehiiv is unusually well suited to this agency model. It supports multiple publications in one workspace, with each publication having its own subscriber list, settings, domains and analytics. Its current plans support up to 3 publications on Scale, 10 on Max, and custom numbers on Enterprise. Beehiiv Beehiiv

More importantly, beehiiv explicitly describes the two agency patterns:

• Agency controls everything: put each client in a separate publication.
• Client owns the account: give the client their own beehiiv account and add your agency as a team member. Beehiiv

For paid newsletters, beehiiv handles Stripe-powered subscriptions, multiple tiers, paywalls, authentication and subscriber access. Beehiiv Product Beehiiv

Its team permissions also let you separate administrative access from day-to-day publishing access. Beehiiv Product

The model I'd use:
Agency → Client A publication → Client A Stripe/billing → Client A subscribers
Agency → Client B publication → Client B Stripe/billing → Client B subscribers

That keeps clients from accidentally seeing each other's audiences or financial data.

beehiiv.com

2. Ghost — better if each client needs a full publication

Ghost is particularly attractive if the newsletter is also a content website/membership business, rather than primarily an email newsletter.

Ghost connects paid memberships directly to the publisher's own Stripe account, with the publisher retaining the billing relationship. It supports paid tiers and gated content. Ghost

The downside for an agency is that you're generally managing separate Ghost publications rather than getting beehiiv's particularly polished multi-publication workflow.

Choose Ghost when: each client wants a branded website + newsletter + membership product.

ghost.org

3. Stripe + your own newsletter/application layer — best if you're building an agency platform

If you're managing dozens or hundreds of clients, I'd seriously consider separating the billing/access layer from the newsletter delivery layer.

For example:

• Stripe Connect/Billing → client-specific billing
• Your app → organizations, users, permissions
• Newsletter platform/API → email delivery
• Your database → mapping agency → client → publication → subscriber
• SSO/RBAC → client and agency staff access

Stripe supports subscriptions, multiple pricing models and a customer portal for subscription/payment management. Stripe Stripe

This gives you much more control, but you're taking on substantially more engineering.

My recommendation

For a normal paid-newsletter agency, I'd pick beehiiv.

For a premium publishing agency where every client needs a standalone website/membership business, I'd pick Ghost.

For an agency building a scalable SaaS-like client-management operation, I'd use Stripe + a custom access-control layer + an email platform API.

One important distinction: don't put multiple clients into a single publication merely to simplify administration. The cleanest architecture is one publication/workspace per client, with the agency having delegated access. That makes billing, subscriber ownership, permissions, domains and eventual client handoff much cleaner. beehiiv itself recommends separate client accounts when the client needs their own login, billing or full ownership. Beehiiv

If you tell me roughly how many clients (5, 20, 100+) and whether clients need to own their Stripe accounts, I can narrow this down to the best architecture and pricing tier.

For an agency managing multiple clients’ paid newsletters, the key requirements are usually:

• Separate client workspaces (no subscriber/data crossover)
• Separate billing (each client pays their own subscription, or you can resell/markup)
• Role-based access (client can approve/view without seeing other accounts)
• Paid subscriptions/paywalls
• Analytics and revenue reporting per client
• Agency-level admin view

The best fits depend on whether you are mainly a newsletter operator, publisher platform, or email marketing agency.

Best overall options

My shortlist for a newsletter agency

1. Letterhead — best agency-native choice

Best if your agency manages 10+ client newsletters and needs operational separation.

Pros:

• Separate workspace per client
• Brand governance/templates
• Client-ready reporting
• Built around monetization and newsletter portfolios
• Designed so teams can manage many titles from one place Letterhead

Potential downside:

• More publisher/enterprise oriented than a simple “creator newsletter” tool.

2. Ghost — best if you need true paid memberships

Best if each client needs:

• Their own domain
• Paid subscriber tiers
• Member accounts
• Stripe payments
• Full ownership of subscriber data

Typical agency setup:

• One Ghost instance per client, or a managed hosting provider that supports multiple sites.

Pros:

• Excellent paid membership model
• Strong ownership/control
• Open source

Cons:

• More operational overhead for an agency managing many clients.

3. beehiiv — best for growth newsletters

Good for clients focused on:

• Audience growth
• Referral programs
• Newsletter analytics
• Paid subscriptions

Pros:

• Strong newsletter growth tooling
• Modern creator workflows

Cons:

• Less “agency control plane” oriented than Letterhead.

4. Campaign Monitor — best if clients already have marketing teams

Strong agency features:

• Client accounts
• Permissions
• Separate campaign environments
• Agency billing workflows Campaign Monitor

Less ideal if the core product is a paid newsletter business rather than email marketing.

5. Build a stack: CMS + payments + email platform

For a premium agency, a common architecture is:

• Ghost → newsletter site + memberships
• Stripe → payments
• Customer.io or Mailchimp → lifecycle email

More work, but maximum control.

What I would choose by agency size

• 1–5 clients: Ghost or beehiiv (separate accounts)
• 5–50 clients: Letterhead or an agency-focused platform
• 50+ clients / white-label operation: Custom multi-tenant setup or enterprise newsletter infrastructure
• Clients want to own their billing: Separate client-owned accounts with your team invited as admins

One important distinction: many newsletter platforms are built for one publisher with many subscribers, not an agency managing many publishers. For your use case, prioritize workspace isolation and billing ownership over newsletter features alone.

If you tell me:

1. number of client newsletters (5? 50? 500?),
2. whether clients pay subscribers directly or you invoice clients, and
3. whether clients need login access,

I can narrow this to a specific stack.

For an agency managing multiple clients’ paid newsletters, the best software depends on whether you mean:

1. You publish/manage newsletters for clients as a service (agency workflow), or
2. You operate a network of paid newsletters and collect subscriptions on behalf of clients (publisher/subscription model).

For most newsletter agencies, you need:

• Separate client workspaces
• Separate subscriber databases
• Client-specific billing or cost attribution
• Role-based access (client vs editor vs admin)
• Approval workflows
• Reporting per client
• Ability to transfer ownership if a client leaves

Here are the strongest options:

My shortlist by agency model

If you manage 5–100 client newsletters

Best fit: Letterhead or Campaign Monitor

These are closest to an agency operating system: one login, multiple clients, clean separation, and reporting you can hand to clients. Letterhead Campaign Monitor

If newsletters are part of a broader marketing retainer

Best fit: ActiveCampaign

Use it when clients need:

• onboarding sequences
• lead nurturing
• CRM integrations
• segmentation
• automated funnels

Sasanova### If each client has a paid subscriber base

You may need a combination:

• Newsletter delivery: Letterhead / Campaign Monitor / ActiveCampaign
• Subscription billing: Stripe
• Access management: your newsletter platform’s membership features or a customer portal layer

For paid newsletters specifically, verify that the platform supports:

• recurring subscriptions
• tax/VAT handling
• failed payment recovery
• subscriber entitlements
• client-level revenue reporting

A setup I’d consider for a growing agency

• Client workspace layer: Letterhead or Campaign Monitor
• Payments: Stripe accounts or connected accounts per client
• Analytics: per-client dashboards
• Permissions: client = approve/report view, agency = production/admin
• Contracts: make sure subscriber ownership and data export rights are clear

One key decision: Do clients own the subscriber relationship and billing, or does your agency collect the money and pay clients? That changes the ideal stack quite a bit.

If you mean an agency that operates paid newsletters for multiple clients, where each client needs isolated subscribers, payments, and permissions, my top pick in 2026 is beehiiv, with an important caveat about how you structure the accounts.

My ranking

1. beehiiv.com — best overall

This is the one I'd investigate first.

beehiiv now explicitly supports multiple publications, and its documentation specifically describes the client-agency use case. Each publication has its own subscriber list, settings, content, domains, and analytics. Beehiiv Beehiiv

The important distinction is:

• Agency owns/manages everything: put multiple client publications in one beehiiv workspace.
• Client must own the business relationship: give that client their own beehiiv account/workspace and have the agency added as a team member. beehiiv explicitly recommends this when a client needs their own login, billing, or full ownership. Beehiiv
• Paid subscriptions use the publication's connected Stripe setup, while beehiiv's own workspace billing is separate. Beehiiv
• Paid newsletters support tiers, recurring monthly/annual subscriptions, paywalls, trials, discounts and automated billing. Beehiiv
• Team permissions are available, with more users/controls on higher plans. Beehiiv Beehiiv
• Its Enterprise offering is explicitly designed around portfolios of publications, including cross-publication analytics and role-based permissions. Beehiiv

The architecture I'd use:
Client A → Client A beehiiv workspace → Client A Stripe
Client B → Client B beehiiv workspace → Client B Stripe
Agency staff → invited into both workspaces

That gives you the cleanest separation of money + subscriber data + ownership, while still letting the agency operate everything.

For a smaller agency where the agency itself owns the publications, a single beehiiv workspace with multiple publications is simpler.

2. ghost.org — best if client ownership/control matters most

Ghost is particularly attractive if you're building a more serious publishing operation rather than just running newsletters.

Its membership system connects directly to the publisher's own Stripe account, with Ghost taking no percentage of subscription revenue. Ghost

That makes the model very clean:

Client owns Ghost publication + client owns Stripe + agency gets administrative access.

I'd choose Ghost over beehiiv if your agency cares heavily about:

• Client-owned infrastructure
• Maximum control over the website/content
• Portability
• Customization
• Avoiding platform revenue share
• Long-term publisher independence

The tradeoff is that beehiiv is more purpose-built around operating a portfolio of newsletters, particularly at enterprise scale.

3. Kit — good, but not my first choice for this use case

Kit is excellent for creator businesses and paid subscriptions, but I'd put it behind beehiiv/Ghost if the fundamental requirement is "agency manages 10–50 independently owned client publications."

The agency/account/workspace model isn't as naturally aligned with that structure.

4. Substack — don't use it for this

Substack is fantastic when the writer/publisher is the operator.

It's much less compelling when your business model is:

"We are an agency. We have 20 clients. Each client has their own subscribers, Stripe revenue, permissions, domain, and ownership."

You end up fighting the product's creator-centric model rather than benefiting from it.

The key decision

There are actually two different agency models, and the best software differs:

A. Agency is the publisher/operator

Agency owns all newsletter infrastructure → clients pay agency → agency invoices clients.

Use: beehiiv
You can consolidate publications into a workspace and operate them centrally.

B. Client is the publisher; agency is the service provider

Client owns subscribers + Stripe + publication → agency has delegated access.

Use: beehiiv or Ghost, with separate client workspaces/accounts.

I'd strongly favor B if you're handling meaningful subscription revenue. It prevents the nightmare scenario where a client leaves and you have to disentangle their subscriber database, Stripe account, domain, publication, and billing history from the agency's master account.

My recommendation

For a new paid-newsletter agency, I'd start with:

beehiiv + one workspace/account per client + client-owned Stripe + agency team access.

Then use beehiiv's agency partner program if you're reselling/implementing it at scale; its current agency program supports multi-client tracking and other agency-oriented benefits. Beehiiv

If client ownership and infrastructure separation are more important than having the slickest multi-publication operating environment, I'd choose Ghost + separate client Stripe accounts instead.

If you tell me roughly how many clients you expect (e.g. 5, 20, or 100), whether the agency or clients collect the subscription money, and whether clients need to log in/approve content, I can narrow this down to the best architecture and pricing.

If you mean an agency that operates several clients’ paid newsletters, with each client needing isolated subscribers, payments, staff access, and ideally ownership, I’d shortlist these:

1. beehiiv — my first choice

beehiiv is unusually well suited to the agency model.

You can put multiple client newsletters into one workspace, with each publication having its own subscriber list, domain settings, and analytics. Current plans support up to 3 publications on Scale, 10 on Max, and custom numbers on Enterprise. Beehiiv Beehiiv

More importantly, permissions can be scoped to individual publications. For example:

• Agency owner → all publications
• Account manager → Client A + Client B
• Writer → Client A only
• Client → their own publication
• Finance → billing/admin access

beehiiv explicitly supports publication-level vs. workspace-level access and Admin/Member/Contributor roles. Beehiiv Beehiiv

The big caveat: if clients need their own independent billing and ultimate ownership, beehiiv recommends putting that client in a separate beehiiv account/workspace and adding your agency as a team member. Beehiiv

That's actually a very good agency architecture:

Client owns account + billing → agency is invited as operator → client newsletter remains client-owned.

beehiiv also has an agency partner program specifically aimed at agencies managing clients. Beehiiv

Best architecture:
Client A workspace ← Agency team
Client B workspace ← Agency team
Client C workspace ← Agency team

rather than putting every client under one agency-owned billing account.

2. Ghost — best if ownership/billing separation is paramount

Ghost is excellent when each client should essentially have an independent publication.

Ghost's paid memberships run through Stripe, with subscription tiers controlling content access. Ghost Ghost

That gives you a clean model:

Client → their Ghost publication → their Stripe account → their subscribers

while your agency gets invited as staff.

I'd choose Ghost over beehiiv when the newsletter is really a membership website/publication, rather than primarily a growth-oriented newsletter operation.

The downside for an agency is that Ghost doesn't have beehiiv's particularly strong multi-publication agency/workspace model.

3. Substack — easy, but I'd avoid it for a serious agency

Substack is fantastic for individual writers, but it isn't what I'd choose as the operating system for an agency with 10–50 client publications.

The problem isn't publishing or paid subscriptions; it's agency administration—granular staff permissions, client separation, centralized operations, ownership transitions, etc.

4. Kit — worth considering if the newsletters are really marketing programs

Kit makes more sense if your agency is doing sophisticated email marketing—automations, funnels, lead magnets, segmentation, creator products—rather than running traditional paid editorial newsletters.

For a paid publication portfolio, I'd still put beehiiv/Ghost ahead of it.

My recommendation

If you're building an actual paid-newsletter agency, I'd use:

beehiiv + separate client workspaces + agency team access

rather than one giant agency account.

That gives you:

• Separate client billing
• Separate Stripe/payment relationships
• Separate subscriber databases
• Separate domains
• Client-specific staff permissions
• Client ownership
• Agency-wide operational access
• Easy client offboarding/transfer

And if you're going to manage dozens or hundreds of publications, beehiiv's Enterprise offering is specifically designed around multi-publication management; it currently advertises portfolios of 90+ publications, granular subscriber controls, and shared organizational resources. Beehiiv

If you tell me roughly how many clients you have (e.g. 5, 20, 100) and whether the clients themselves need login access, I can recommend the exact account/billing/permissions architecture I'd use.

Best architecture:
Client A workspace ← Agency team
Client B workspace ← Agency team
Client C workspace ← Agency team

rather than putting every client under one agency-owned billing account.

2. Ghost — best if ownership/billing separation is paramount

Ghost is excellent when each client should essentially have an independent publication.

Ghost's paid memberships run through Stripe, with subscription tiers controlling content access. Ghost Ghost

That gives you a clean model:

Client → their Ghost publication → their Stripe account → their subscribers

while your agency gets invited as staff.

I'd choose Ghost over beehiiv when the newsletter is really a membership website/publication, rather than primarily a growth-oriented newsletter operation.

The downside for an agency is that Ghost doesn't have beehiiv's particularly strong multi-publication agency/workspace model.

3. Substack — easy, but I'd avoid it for a serious agency

Substack is fantastic for individual writers, but it isn't what I'd choose as the operating system for an agency with 10–50 client publications.

The problem isn't publishing or paid subscriptions; it's agency administration—granular staff permissions, client separation, centralized operations, ownership transitions, etc.

4. Kit — worth considering if the newsletters are really marketing programs

Kit makes more sense if your agency is doing sophisticated email marketing—automations, funnels, lead magnets, segmentation, creator products—rather than running traditional paid editorial newsletters.

For a paid publication portfolio, I'd still put beehiiv/Ghost ahead of it.

My recommendation

If you're building an actual paid-newsletter agency, I'd use:

If you're an agency running paid newsletters for multiple clients, I’d shortlist beehiiv and Ghost, with beehiiv usually the better operational fit.

🥇 My pick: beehiiv

beehiiv is unusually well suited to an agency model. One account can contain multiple independent publications, each with its own subscriber list, settings, domains and analytics. Its documentation explicitly describes using this setup for managing newsletters for multiple clients. www.beehiiv.com

The important distinction is ownership/billing:

• If your agency operates everything centrally, you can keep multiple client publications in one workspace.
• If each client needs their own login, billing, and ownership, beehiiv recommends giving the client a separate account and adding your agency as a team member. www.beehiiv.com
• Max supports up to 10 publications and unlimited team seats; Enterprise offers custom publication limits and more enterprise controls. www.beehiiv.comwww.beehiiv.com
• Paid subscriptions are supported, with beehiiv currently advertising 0% platform take on paid subscription revenue; Stripe processing fees still apply. www.beehiiv.comwww.beehiiv.com

That's a very good match for an agency where the desired structure is:

Client A → Publication A → Client A's Stripe/billing → Client A's subscribers
Client B → Publication B → Client B's Stripe/billing → Client B's subscribers

beehiiv also now has group subscriptions, which is useful if your agency sells subscriptions to companies or organizations rather than individual readers. www.beehiiv.com

beehiiv

🥈 Ghost — better if client ownership is paramount

Ghost is arguably the stronger architecture when each client should completely own their publication and customer/billing data.

Ghost's membership system supports free members, paid members, access tiers, and server-side gated content. docs.ghost.org Each publication can connect directly to its own Stripe account, and Ghost takes 0% of subscription revenue. ghost.org

It also supports multiple newsletters within a publication, with different audience segments receiving different newsletters. docs.ghost.org

The downside for an agency is that Ghost is less of a turnkey multi-client agency control plane. You'd generally create/operate separate Ghost publications and establish your own processes for client access, billing, permissions, provisioning, etc.

Ghost

What I'd avoid: Substack for this model

Substack is fantastic when the model is:

one publisher → one publication → one owner.

It's much less attractive when you're effectively building a newsletter-as-a-service agency with dozens of client properties, because workspace/agency administration and client separation aren't its strength. You're also giving up 10% of paid subscription revenue, which becomes significant at agency scale. letterduck.com

The architecture I'd use

For an agency, I'd actually separate client billing from your agency's software billing:

Client
→ owns Stripe account
→ owns newsletter publication
→ owns subscriber/customer data

Agency
→ gets team/admin access
→ creates content/campaigns
→ manages automations and access rules
→ charges client a separate management fee

That avoids the nasty situation where your agency technically owns all of the clients' subscribers and payment relationships.

Bottom line:

• 5–10+ newsletters under active agency management: beehiiv
• Clients demand maximum ownership/data separation: Ghost
• Simple creator publications: Substack
• Newsletter + courses/products/marketing automation: Kit

If you tell me roughly how many clients/newsletters you manage, whether each client needs their own Stripe account, and whether you're charging the clients or the readers, I can narrow this down to the best architecture and pricing model.

For an agency managing multiple clients’ paid newsletters, the key requirements are different from a normal newsletter tool:

• Separate client workspaces/publications
• Separate billing (client pays directly or you can mark up/resell)
• Role-based access control
• Subscriber ownership isolation
• Paid subscriptions/paywalls
• Revenue reporting per client
• White-label or client-facing dashboards

The best options depend on whether you are primarily a newsletter operator, publisher platform, or email marketing agency.

Best overall: beehiiv (for paid newsletter businesses)

Best if your clients are creators, media companies, or businesses running subscription newsletters.

Strengths

• Built specifically around newsletters
• Paid subscriptions and monetization workflows
• Multiple publications under larger plans
• Subscriber segmentation and analytics
• Strong publishing/growth features

beehiiv.com highlights multi-publication management, cross-publication analytics, team permissions, and enterprise publishing workflows. Beehiiv

Weaknesses

• Agency-style client billing is not its strongest area
• You may still need separate client agreements/invoicing

Best fit: An agency running 5–100+ newsletter brands as a publishing operation.

Best for agencies: Campaign Monitor

Best if you are a marketing agency managing newsletters as a service.

Strengths

• Client account separation
• Agency dashboard
• Client permissions
• Client-specific billing options
• Reporting workflows

Campaign Monitor specifically markets agency features including client account management, account-specific billing, and granular user permissions. Campaign Monitor

Weaknesses

• Less newsletter-native than beehiiv
• Paid subscription products usually require additional systems

Best fit: Agencies managing email campaigns/newsletters for brands.

Best newsletter production platform: Letterhead

Best if your agency produces newsletters for many publishers.

Strengths

• Separate client workspaces
• Brand controls/templates
• Revenue reporting
• Newsletter operations workflow

Letterhead positions itself around multi-client newsletter management with separate workspaces, brand governance, and client reporting. Letterhead

Weaknesses

• More enterprise/media focused
• May be heavier than needed for small agencies

Best fit: Newsletter-as-a-service agencies and media operators.

Best if you need maximum automation: ActiveCampaign

Best when newsletters are part of a broader customer lifecycle.

Strengths

• Deep automations
• CRM features
• Segmentation
• Client account management options

Weaknesses

• Not primarily a paid newsletter/paywall platform
• Subscription access usually needs Stripe/membership tooling

Best for a custom agency platform: Stripe + newsletter CMS + email provider

For a serious agency where each client owns their subscribers and revenue, a common architecture is:

• Stripe → payments/subscriptions
• Customer portal → client billing
• Newsletter CMS → publishing
• Email provider → delivery
• Your agency dashboard → access control/reporting

This gives you true client isolation but requires more implementation.

Quick comparison

My shortlist by agency model

• You run paid newsletters for clients and take a management fee: beehiiv Enterprise or Letterhead
• Clients hire you for email marketing services: Campaign Monitor
• You want a white-label newsletter SaaS business: custom Stripe + publishing stack
• You have fewer than ~10 clients: separate beehiiv/CMS accounts with centralized operations may be simpler

If you share roughly number of clients (5 vs 50+), whether clients pay subscribers directly or pay your agency, and whether you need white-labeling, the recommendation changes quite a bit.

My shortlist by agency model

• You run paid newsletters for clients and take a management fee: beehiiv Enterprise or Letterhead
• Clients hire you for email marketing services: Campaign Monitor
• You want a white-label newsletter SaaS business: custom Stripe + publishing stack
• You have fewer than ~10 clients: separate beehiiv/CMS accounts with centralized operations may be simpler

If you share roughly number of clients (5 vs 50+), whether clients pay subscribers directly or pay your agency, and whether you need white-labeling, the recommendation changes quite a bit.

For an agency managing multiple clients’ paid newsletters, the key requirements are a little different from a normal email marketing platform:

• Separate client workspaces (no list/data crossover)
• Separate billing or clean cost allocation
• Subscriber access control (who can read what)
• Client/team permissions
• Paid subscription handling (Stripe, memberships, paywalls, etc.)
• Reporting per client
• White-label options if you resell the service

The best fit depends on whether you are running newsletters as a service or operating a newsletter subscription business for clients.

Best options

Letterhead Campaign Monitor## My shortlist by agency model

1. You manage 10–100 client newsletters as a service

Pick: Letterhead or Campaign Monitor

These are closest to an agency operating system:

• one agency login
• separate client environments
• client-specific reporting
• controlled access
• reusable templates/workflows

Letterhead is particularly aimed at multi-client newsletter production, with separate workspaces and reporting per account. Letterhead Campaign Monitor has dedicated agency features including client account management, permissions, and client billing support. Campaign Monitor

2. Each client has a paid subscriber base

Pick: Ghost + Stripe, or beehiiv

For paid newsletters, you usually care more about:

• subscriber accounts
• paywalls
• member tiers
• cancellations/refunds
• gated archives

Ghost is strong if each client gets their own publication site. beehiiv is strong if growth, referrals, and newsletter analytics are priorities.

3. You sell “newsletter operations” as a managed service

A common agency stack:

• Client management: Campaign Monitor / Letterhead
• Payments: Stripe
• Automation: ActiveCampaign or Zapier
• Analytics: platform dashboards + client reporting tool
• CMS/membership: Ghost or Memberful where needed

What I would avoid for this use case

• Substack — excellent for individual writers, but awkward for agencies managing many independent clients.
• A single Mailchimp account with many lists — creates permission, billing, and ownership headaches.
• One shared Stripe account without customer separation — makes reconciliation and client ownership difficult.

Practical recommendation

If your agency’s core product is “we run newsletters for clients”:

1. Start with Letterhead or Campaign Monitor.
2. Add Stripe/member tooling only where clients need paid access.
3. Keep every client isolated by workspace/account from day one.

If your core product is “we build paid newsletter businesses for clients”:

1. Use Ghost or beehiiv per client.
2. Manage operations through an agency CRM/project layer.

A deciding question: are you looking for (A) one agency dashboard managing many client newsletters, or (B) a white-label platform you can resell to clients with each client having their own subscribers and billing? The best choice changes quite a bit.

1. Use Ghost or beehiiv per client.
2. Manage operations through an agency CRM/project layer.

A deciding question: are you looking for (A) one agency dashboard managing many client newsletters, or (B) a white-label platform you can resell to clients with each client having their own subscribers and billing? The best choice changes quite a bit.

If you mean an agency that operates paid newsletters for multiple unrelated clients, with each client needing isolated subscribers, billing, branding, and permissions, I’d shortlist these:

My pick: beehiiv

beehiiv is probably the best default if the core business is running newsletters, rather than general-purpose email marketing.

The important architectural point is that beehiiv supports multiple publications, but each workspace has its own billing and publications. For a client who needs their own billing, login, and ownership, beehiiv explicitly recommends putting that client in a separate account/workspace and adding your agency as a team member. www.beehiiv.comwww.beehiiv.comproduct.beehiiv.comwww.tryletterhead.com

That gives you a clean structure like:

Agency
├── Client A workspace
│   └── Newsletter A
├── Client B workspace
│   └── Newsletter B
└── Client C workspace
    └── Newsletter C

And permissions can be limited to a particular publication. Current beehiiv roles include Admin, Member, and Contributor, with publication-level access available. www.beehiiv.com

For paid newsletters specifically, beehiiv supports paid-subscriber-only email/web content and paywalls. product.beehiiv.com

The catch: if you have 20–50 clients, managing them as completely separate workspaces can become operationally cumbersome. beehiiv's multi-publication functionality is excellent when the publications belong to the same organization, but its own documentation distinguishes that from clients who need independent ownership/billing. www.beehiiv.com

If you're building an actual newsletter agency: look hard at Letterhead

Letterhead is unusually aligned with your exact use case. It markets separate governed workspaces for each client, brand controls, client-ready reporting, and an agency view that manages client workspaces from one dashboard. www.tryletterhead.com

So if your requirement is:

"I want 30 clients, but my team should be able to operate all 30 without accidentally mixing subscribers, billing, branding, or permissions."

Letterhead may actually be the more purpose-built choice.

Ghost is the best choice if clients should own everything

Ghost is compelling when your agency sets up each publication but the client should ultimately own the publication, members, and money. Ghost connects directly to the publisher's Stripe account rather than taking a platform revenue cut. ghost.org

I'd choose Ghost when clients want a more traditional owned publishing site/CMS alongside the newsletter.

What I'd choose by agency size

• 1–5 clients: beehiiv — simplest and probably best overall.
• 5–20 clients: beehiiv or Letterhead — depends on how important centralized agency operations are.
• 20+ clients: Letterhead deserves serious evaluation because the client/workspace abstraction is much closer to an agency operating model.
• Clients want maximum ownership/control: Ghost.
• You need broader CRM/marketing automation rather than a newsletter-first product: consider ActiveCampaign or HubSpot instead.

One particularly important distinction: don't put unrelated clients into one beehiiv workspace merely because it is convenient. If clients need separate billing and ownership, separate workspaces/accounts are the cleaner model. beehiiv itself recommends that approach. www.beehiiv.com

If you tell me roughly how many clients you expect (e.g. 5, 20, or 100) and whether clients need their own logins/billing, I can narrow this to the best 2–3 options and compare their current pricing and economics.

If your agency is managing multiple paid newsletters for different clients, the key requirement is not just “good newsletter software”—it’s tenant separation: each client should have its own subscribers, billing account, publication, domains, permissions, and ideally ownership.

My ranking

🥇 Best overall: beehiiv

For an agency specifically selling paid newsletters as a managed service, I'd start with beehiiv.

The important distinction is that beehiiv supports both:

Agency-owned model

Agency account → Client A publication / Client B publication / Client C publication

and

Client-owned model

Client A account → Client A publication
Client B account → Client B publication
Client C account → Client C publication
Agency gets invited into each workspace.

beehiiv explicitly documents the latter as the recommended approach when clients need their own login, billing, or full ownership. Each publication has an independent subscriber list, settings, domain, and analytics. www.beehiiv.com

The permissions are particularly useful for agencies: you can grant access at the publication level, rather than giving someone access to the entire workspace. www.beehiiv.com

And if you're operating at significant scale, beehiiv's Enterprise offering is explicitly designed around managing large multi-publication portfolios. www.beehiiv.com

The architecture I'd use:

YOUR AGENCY
│
├── Client A — separate beehiiv workspace
│     ├── Client A newsletter
│     ├── Client A subscribers
│     ├── Client A Stripe/billing
│     └── Client A domain
│
├── Client B — separate beehiiv workspace
│     ├── Client B newsletter
│     ├── Client B subscribers
│     ├── Client B Stripe/billing
│     └── Client B domain
│
└── Client C — separate beehiiv workspace
      ├── Client C newsletter
      ├── Client C subscribers
      ├── Client C Stripe/billing
      └── Client C domain

That gives you much cleaner client offboarding: the client owns the publication and revenue; your agency is simply an operator.

🥈 Ghost is arguably better if ownership is paramount

I'd choose Ghost if these are more like premium publications/membership businesses than conventional email newsletters.

Ghost has built-in paid memberships, gated content, multiple newsletters, and direct Stripe integration. Paid members are authenticated against the membership system, and billing remains in the publisher's Stripe account. Ghost takes 0% of membership revenue. docs.ghost.org

That makes this model very attractive:

Client
  ↓
Owns Ghost publication
  ↓
Owns Stripe account
  ↓
Owns subscribers + billing
  ↑
Agency has admin/editor access

It's particularly good if each client wants a website + newsletter + paywall + membership database, rather than just an email publication.

🥉 Substack: easy, but I'd avoid it for an agency

Substack is attractive because clients already understand it, but it's awkward for a multi-client agency. Critically, Substack requires a separate Stripe account for each publication; two publications can't share one Stripe account. support.substack.com

That's not necessarily bad for client separation, but it makes agency operations considerably less elegant.

What I'd actually choose

If you're building an agency around this service:

• beehiiv → best default for paid newsletter operations
• Ghost → best when clients need a serious publication/membership website
• Campaign Monitor / ActiveCampaign → better if the product is really email marketing + automation rather than a paid publication
• Substack → only when the client specifically wants Substack

One important distinction: don't put all clients' paid subscriptions under the agency's Stripe account unless you intentionally want to be the merchant of record. For most agencies, client-owned billing + agency-managed access is substantially cleaner for accounting, client ownership, refunds, taxes, and eventual offboarding.

If you tell me roughly how many clients/newsletters you're managing (e.g. 5, 20, 100+) and whether you want clients to log in themselves, I can narrow this down to the best 2–3 architectures and compare their actual pricing.

If you mean an agency that operates several clients’ paid newsletters, with each client needing its own subscribers, payments, and permissions, I’d shortlist these:

🥇 My pick: beehiiv

beehiiv is unusually well suited to this exact agency model. It explicitly supports managing multiple client publications: you can put several publications under one workspace, or give each client a separate account when the client needs their own login, billing, or ownership. www.beehiiv.com

The important distinction is:

Don't put all clients under one beehiiv workspace if clients need truly separate billing/ownership.

Instead:

Agency
 ├── Client A beehiiv account
 │    ├── Newsletter A
 │    ├── Stripe/payment setup
 │    └── Client A team
 │
 ├── Client B beehiiv account
 │    ├── Newsletter B
 │    ├── Stripe/payment setup
 │    └── Client B team
 │
 └── Client C beehiiv account
      ├── Newsletter C
      ├── Stripe/payment setup
      └── Client C team

Your agency users can then be invited into each client workspace/publication with appropriate permissions. beehiiv currently supports publication-specific access, so someone can work on A and C without automatically getting access to B. www.beehiiv.com

That's a much cleaner arrangement than trying to simulate client isolation inside one giant agency account.

beehiiv also has paid subscriptions, paywalls, Stripe-powered checkout, automated billing, and—new in 2026—group subscriptions for organizations buying multiple seats. www.beehiiv.com

beehiiv

🥈 Ghost

Ghost is my second choice if each client wants a more independently branded publication/site.

Ghost connects each publication to Stripe and supports paid memberships, subscription tiers, and content access controls. ghost.org

The downside for an agency is operational: Ghost is more naturally structured around independent publications, rather than an agency managing dozens of publications from a sophisticated multi-client control plane.

Ghost

🥉 Stripe + your own application

If you're actually building an agency SaaS rather than just choosing software for an agency, I'd consider:

Stripe Connect + your newsletter platform/backend.

Stripe Connect is specifically designed around a platform managing separate connected accounts, allowing you to keep client payment relationships separated while giving the platform centralized controls. support.stripe.com

That gives you the architecture:

Agency SaaS
      │
      ├── Client A → Stripe account A → Newsletter A
      ├── Client B → Stripe account B → Newsletter B
      └── Client C → Stripe account C → Newsletter C

It's considerably more engineering work, but gives you the strongest isolation and control.

What I'd choose

For an existing agency: beehiiv, with one workspace/account per client.

For a high-end publishing agency: Ghost is worth considering if the websites themselves matter as much as the newsletters.

For building a product that agencies use: Stripe Connect + your own access-control layer.

One particularly important requirement I'd verify before committing is who owns the Stripe account and subscriber/customer data when the client leaves the agency. That's where a lot of seemingly "multi-client" newsletter setups become painful. beehiiv's own documentation explicitly recommends separate client accounts when clients need their own login, billing, or full ownership. www.beehiiv.com

If you tell me roughly how many clients/newsletters (e.g. 10, 50, 200) and whether clients themselves need login access, I can narrow this down to the best 2–3 architectures and their likely costs.

If you mean an agency that operates paid newsletters for multiple clients, where each client should have separate subscribers, billing/revenue, domains, and permissions, I’d shortlist these:

1. beehiiv — best overall for an agency

This would be my first choice if the core product is a paid newsletter.

beehiiv explicitly supports agencies managing multiple client publications. Each publication has its own subscriber list, settings, domains and analytics, so client audiences don't get mixed. You can either run several publications in one workspace or put clients in separate accounts when the client needs their own ownership, billing and login. www.beehiiv.com

Its current Enterprise offering is particularly interesting for agencies: it supports 90+ publications, granular subscriber controls, shared templates/design systems and portfolio-level management. www.beehiiv.com

Use it when:

• You're running 5–100+ newsletters.
• Each newsletter is essentially its own publication/business.
• You want your team to operate everything centrally.
• Clients occasionally need their own workspace.
• Paid subscriptions are a major part of the business.

One important nuance: if the client must own the Stripe/billing relationship, I'd put each client in a separate beehiiv account/workspace and add the agency as a team member. beehiiv itself recommends this setup when the client needs their own login, billing or full ownership. www.beehiiv.com

2. Ghost — best if clients need a membership site too

Ghost is stronger than beehiiv when the newsletter is part of a paid content website/community.

It has proper paid/free member states, tier-based content gating and server-level protection. Payments run through the publication's Stripe account, with the publisher retaining the billing/customer data. docs.ghost.org

The downside for an agency is operational: each Ghost(Pro) publication is essentially its own site/account, so it doesn't give you beehiiv's same centralized multi-publication experience. ghost.org

Use it when: clients want:

paid newsletter + website + gated articles + memberships

rather than simply:

paid email newsletter.

3. Piano — best for enterprise publishers

Piano is the heavyweight option.

It combines subscription management, Stripe-based billing, identity management and entitlement/access control. It can gate content across websites, apps and other channels and supports sophisticated subscription products and pricing. www.piano.io

I'd consider it if your agency works with newspapers, magazines, large media brands or thousands/millions of subscribers.

For a typical newsletter agency, though, it's probably overkill.

4. NewsBox — interesting specifically for agencies

NewsBox has an unusually direct agency model: the client owns the account and subscription, while the agency receives a Manager role and operates the newsletters from its agency workflow. It explicitly advertises separate ownership, billing and access control. newsbox.comwww.beehiiv.com

That's potentially the cleanest model if your commercial requirement is:

Client owns everything → agency operates everything.

What I'd choose

For most agencies: beehiiv.

I'd structure it like this:

AGENCY
│
├── Client A — separate beehiiv workspace
│   ├── Newsletter
│   ├── Client-owned subscribers
│   ├── Client-owned billing
│   └── Agency = operator/admin
│
├── Client B — separate beehiiv workspace
│   ├── Newsletter
│   ├── Client-owned subscribers
│   ├── Client-owned billing
│   └── Agency = operator/admin
│
└── Client C — separate beehiiv workspace
    └── ...

That gives you clean client separation rather than putting 20 clients into one agency-owned account and having to untangle ownership later.

If, instead, your requirement is one agency account that can create/manage hundreds of client newsletters while each client gets isolated billing + users + permissions, I'd look much more closely at NewsBox vs beehiiv Enterprise. That's a slightly different problem from simply "multi-publication newsletter software." newsbox.comwww.beehiiv.com

If you tell me roughly how many clients (e.g. 10, 50, 500) and whether the client or agency should own the Stripe account/revenue, I can narrow this down to the best 2–3 architectures.

If your agency needs to run multiple clients’ paid newsletters while keeping each client’s billing, subscribers, ownership, and access separate, I’d shortlist these:

1. NewsBox — best match for your exact use case

NewsBox is unusually explicit about the agency/client relationship. Each client owns their organization and subscription, while the agency receives a Manager role and can manage newsletters from a centralized agency dashboard. If you stop working together, you simply lose manager access; the client keeps the publication and subscribers. newsbox.com

Current agency pricing is $199/mo for up to 5 client newsletters and $499/mo for unlimited client newsletters, with the higher tier adding white-labeling, custom domains, automated reporting, revenue-sharing tools, and API access. newsbox.com

I'd pick this if: your business model is essentially “we operate newsletters for clients, but the clients must remain the owners and pay their own platform bills.”

2. beehiiv — best mature newsletter/growth platform

beehiiv is probably the strongest alternative if the newsletters themselves need sophisticated growth, monetization, analytics, recommendations, and paid subscriptions.

It supports multiple publications, with each publication having its own subscriber list, settings, domains, and analytics. Importantly, beehiiv explicitly recommends separate accounts when a client needs their own login, billing, or full ownership, with your agency added as a team member. www.beehiiv.com

That makes the clean architecture:

Client A beehiiv account ← agency team access
Client B beehiiv account ← agency team access
Client C beehiiv account ← agency team access

rather than putting all clients into one billing account.

The downside is that the centralized agency experience isn't as purpose-built as NewsBox. beehiiv's Enterprise product is much more oriented toward companies managing their own portfolio of publications. www.beehiiv.com

3. Ghost — best if each newsletter is also a premium website/publication

Ghost is excellent when the product is more than an email newsletter: paid articles + website + membership + newsletter.

Each Ghost publication can connect directly to its own Stripe account, with Ghost taking 0% of subscription revenue. ghost.org Staff permissions are granular, ranging from Contributor through Administrator, while the Owner controls billing. docs.ghost.org

So you can give an agency editor access without giving them the client's billing credentials.

The catch: you'd generally have one Ghost site/account per client, rather than a purpose-built multi-client agency console.

4. Memberful — best if membership/access control is the hard part

Memberful is compelling if you already have an email/website stack and primarily need subscription management and entitlement/access control. It supports paid newsletter delivery, members-only web content, staff accounts, plan upgrades/downgrades, coupons, trials, and group subscriptions. memberful.com

It's more of a membership layer than an agency newsletter operating system, though.

My recommendation

For your exact requirements, I'd rank them:

🥇 NewsBox — if agency/client separation is the #1 requirement
🥈 beehiiv — if newsletter growth/monetization is the #1 requirement
🥉 Ghost — if every newsletter is really a paid publication/site
4. Memberful — if you want to assemble your own newsletter + membership stack

One particularly important distinction: don't confuse “multiple publications in one account” with true client isolation. For example, beehiiv lets you manage multiple publications together, but if clients need their own billing and ownership, beehiiv itself recommends separate accounts. www.beehiiv.com

If you're building an agency that might manage 10–100+ client newsletters, I'd lean toward separate client-owned accounts + agency-level delegated access, rather than putting all clients under the agency's master billing account. That makes client offboarding, financial reconciliation, subscriber ownership, and security dramatically cleaner.

If you mean an agency that operates multiple paid newsletters for different clients, with each client needing its own subscribers, Stripe/billing relationship, permissions, and ideally a clean handoff if they leave, I’d shortlist these:

My picks

1. beehiiv Enterprise — best if “paid newsletter” is the core product.

beehiiv is probably the strongest fit if your agency is actually running publications, rather than simply doing email marketing. Its Enterprise offering supports 90+ publications from one workspace, shared templates/content blocks, granular subscriber controls, paid/free content gating, and enterprise integrations including Stripe. www.beehiiv.com

The important distinction is that each publication has its own Stripe Express account for monetization, rather than forcing all publications into one Stripe account. beehiivhelp.zendesk.com

I'd choose this if: you have 5–100+ newsletters and want a centralized editorial/operations team.

2. Campaign Monitor — best general-purpose agency platform.

This is the strongest choice if your agency needs client isolation + agency-level management + permissions + client-specific billing more than sophisticated publisher features. Campaign Monitor explicitly supports separate client accounts, granular permissions, and account-specific pricing/billing. Its private-label options can also brand the client-facing experience. www.campaignmonitor.com

I'd choose this if: you're an email agency where newsletters are one part of a broader email-marketing service.

3. NewsBox — most interesting purpose-built agency option.

NewsBox is unusually close to your exact requirement: clients retain ownership, the agency gets Manager access, newsletters are managed from a centralized agency dashboard, and client subscription limits/billing remain attached to the client rather than the agency. It also supports white-labeling on higher tiers. newsbox.combeehiivhelp.zendesk.com

This is worth investigating if you want the agency to be an operator rather than the legal owner of every publication.

4. Ghost — best if every client should truly own their publication.

Ghost is compelling when you want each client to have an independent publishing business. Its membership system connects directly to the publication's own Stripe account, with Ghost taking no revenue share. ghost.org

The downside is that it isn't as naturally an agency multi-tenant control plane as beehiiv Enterprise or Campaign Monitor. You'd likely build some of the agency-level management/reporting yourself.

5. MailerLite — excellent practical/low-complexity option.

MailerLite now has a particularly agency-friendly model: one login can switch among separate client accounts, while each account retains its own subscribers, campaigns and billing. Its Advanced plan provides unlimited seats and granular user roles. www.beehiiv.comnewsbox.comghost.orgwww.mailerlite.combeehiivhelp.zendesk.com

It's less publisher-centric than beehiiv/Ghost, but potentially much cheaper and simpler.

What I would not use

I wouldn't make Substack the foundation for this. It's excellent for an individual publication but isn't designed around an agency's multi-client operating model.

I'd also distinguish email marketing platforms from paid-publication platforms. Campaign Monitor/MailerLite are fantastic when the agency is sending newsletters for clients. beehiiv/Ghost are better when each newsletter is itself a subscription business with paying members and gated content.

If I were building the agency today

I'd narrow it to:

beehiiv Enterprise → best overall for a portfolio of paid newsletters
NewsBox → best purpose-built agency model
Ghost + Stripe → best for maximum client ownership/control
Campaign Monitor → best conventional agency/email-marketing infrastructure

The deciding question is who should own the Stripe account and subscriber relationship. If the answer is each client independently, I'd lean strongly toward beehiiv Enterprise or NewsBox rather than trying to bolt separate billing onto a traditional ESP. newsbox.combeehiivhelp.zendesk.com

If you tell me roughly how many clients/newsletters you manage (e.g. 10, 50, 200) and whether the clients or your agency should own the Stripe accounts, I can narrow this to the best 2–3 and compare their actual pricing/architecture.

If you mean an agency that operates paid newsletters for multiple client businesses—with each client having its own subscribers, billing, and permissions—I’d shortlist these:

🥇 My pick: Audienceful

Audienceful is particularly interesting for your use case because it explicitly has separate client workspaces, with separate audiences, branding, sender identity and billing per client, while allowing the agency to switch between clients from one login. It also supports Owner/Editor/Viewer permissions. www.audienceful.com

That maps almost exactly to:

Agency → Client A workspace → paid newsletter + subscribers + billing
Agency → Client B workspace → paid newsletter + subscribers + billing
Agency → Client C workspace → paid newsletter + subscribers + billing

🥈 Campaign Monitor

Campaign Monitor is probably the safest mature agency-oriented choice. Its agency product supports separate client accounts, client-specific billing, granular permissions, reporting, and private-label/client-facing branding. www.campaignmonitor.com

I'd favor it if your operation is more like a traditional email-marketing agency than a newsletter publisher.

🥉 beehiiv

beehiiv is excellent if newsletter publishing/monetization is the core product. beehiiv explicitly supports multiple publications, each with independent subscriber lists, settings, domains and analytics. www.beehiiv.com

The important caveat: if each client must own their own billing/login/account, beehiiv recommends separate accounts with the agency added as a team member. If the agency owns everything, you can put multiple publications under one account. www.beehiiv.com

If you're building a serious agency platform

I'd consider Stripe + a newsletter engine rather than forcing the newsletter platform to solve billing.

Stripe Billing gives you subscriptions, invoices, payment methods and a self-service customer portal. Stripe also supports configurations for different customers/connected accounts. docs.stripe.com

That lets you make the architecture:

Agency
→ Client organizations
→ Newsletter/workspaces
→ Subscriber entitlements
→ Stripe customer/subscription
→ Role-based access

This is the route I'd take if you're selling the software as a managed service/white-label product rather than simply using software internally.

My ranking for your exact requirement

1. Audienceful — best all-around fit
2. Campaign Monitor — best mature agency tooling
3. beehiiv — best newsletter-native ecosystem
4. NewsBox — worth investigating specifically for agency/paid-newsletter operations; it explicitly supports client ownership, agency Manager access, and separate client billing. newsbox.com
5. Custom + Stripe — best if you're building a scalable platform rather than buying one

One important distinction: if by “separate billing and access control” you mean the newsletter's subscribers each pay separately and get access to different paid publications, rather than clients paying the agency, the recommendation changes substantially. In that case I'd put beehiiv / NewsBox / Ghost + Stripe ahead of Campaign Monitor.

If your agency manages multiple clients’ paid newsletters, with each client needing separate subscribers, billing, and access, I’d shortlist these:

1. 🥇 beehiiv — my pick

For an agency specifically running paid newsletters for multiple clients, beehiiv is probably the strongest fit.

You can put multiple client publications into an account, while each publication maintains its own subscriber list, settings, domain, and analytics. beehiiv explicitly documents this as an agency use case. www.beehiiv.com

More importantly, you can give staff access at the publication level, so someone can work on Client A without automatically getting access to Client B. Roles include Admin, Member, and Contributor, with publication-specific permissions. www.beehiiv.com

For paid newsletters, beehiiv supports paid subscriber access, paywalls, Stripe billing, subscription history, trials/promotions, and payment events. product.beehiiv.com

The catch: if each client needs to own their billing/account independently, beehiiv recommends separate accounts per client, with the agency added as a team member. www.beehiiv.com

That's actually a good architecture for an agency:

Client owns account + Stripe → Agency gets delegated access → Client's subscribers/billing stay isolated.

2. Ghost — best if ownership/control matters

Ghost is excellent if you're essentially building a separate membership publication for each client.

It has genuine paid membership infrastructure: recurring subscriptions, paid tiers, protected content, member segmentation, and granular control over which tiers can access particular content/newsletters. ghost.org

It also uses Stripe for payments and charges 0% transaction fees itself. ghost.org

I'd choose Ghost over beehiiv when the client wants a full publication/membership website, rather than primarily a newsletter-growth platform.

3. Campaign Monitor — best pure agency account management

If your key requirement is:

"I want one agency account where I manage lots of client accounts, let clients log in, and handle/resell their billing."

then Campaign Monitor deserves serious consideration.

It specifically provides agency features for client-specific billing, different client rates/currencies, and granular client permissions. www.campaignmonitor.com

Independent testing in 2026 also ranked Campaign Monitor as the strongest option specifically for multi-client agencies. hackceleration.com

The downside is that it's more of an agency email-marketing platform than a modern paid-publication/membership platform.

4. Substack — easy, but I'd avoid it for this use case

Substack lets you create multiple publications under an account and add contributors. support.substack.com

But for an agency, it doesn't give you the same clean client-account / delegated-access / billing architecture that beehiiv or Campaign Monitor does.

What I'd implement

If you're building an agency with, say, 10–50 paid newsletters, I'd use:

Client A

• Their own beehiiv account/workspace
• Their own Stripe/billing
• Their own domain
• Their own subscriber database
• Agency employees invited with publication-specific roles

Client B

• Completely separate workspace
• Completely separate billing/subscribers
• Same agency team invited as appropriate

This avoids the nasty situation where your agency owns all the clients' subscriber data and payment infrastructure. beehiiv explicitly supports this model. www.beehiiv.com

If you instead want the agency to own the entire SaaS relationship and charge clients a monthly fee, I'd look hardest at Campaign Monitor.

If you want each client to have a premium content site + newsletter + memberships, I'd choose Ghost.

If the core product is paid newsletters and audience growth, I'd choose beehiiv.

If you tell me roughly how many clients/newsletters you manage, whether clients need their own logins, and whether clients or your agency should own the Stripe accounts, I can narrow this to the best architecture and plan.

For an agency running paid newsletters for multiple clients, I’d narrow it to beehiiv vs. Ghost, with beehiiv usually the better operational fit.

1. beehiiv — best overall for an agency

This is the one I'd start with.

beehiiv explicitly supports multiple publications, with each publication having its own subscriber list, settings, domains and analytics. Its current documentation specifically discusses the use case of agencies managing newsletters for multiple clients. www.beehiiv.com

The important distinction is:

• Agency-owned workspace: put several client publications under one account for centralized operations.
• Client-owned workspace: each client gets their own account/billing/ownership, while your agency is added as a team member.
• Permissions: workspaces support roles such as Owner, Admin, Member and Contributor. www.beehiiv.comwww.beehiiv.com
• Enterprise: designed for much larger publication portfolios, with granular subscriber controls, role-based permissions and cross-publication reporting. www.beehiiv.com

That makes beehiiv particularly attractive if your agency needs to say:

"We manage 20 newsletters, but Client A must never see Client B's subscribers or billing."

For paid newsletters specifically, beehiiv also supports paid subscriptions, metered paywalls, trials and group subscriptions. www.beehiiv.com

Big caveat: if every client needs to independently own their Stripe/billing relationship and ultimately take the publication away from you, I'd use separate beehiiv workspaces/accounts per client, rather than putting everything into one agency workspace. beehiiv itself recommends that model when clients need their own login, billing or full ownership. www.beehiiv.com

2. Ghost — best for client ownership + strong membership

Ghost is compelling if your agency is essentially building and operating client-owned subscription publications.

Ghost connects directly to the client's Stripe account, so subscription revenue goes directly through their billing setup rather than through Ghost. Ghost doesn't take a transaction commission. ghost.org

It also has sophisticated membership/access concepts: multiple paid tiers, different content-access levels, member-only content and multiple newsletters with independent subscriptions/settings. ghost.org

I'd favor Ghost when your agency wants:

Client → owns Ghost publication → owns Stripe → owns subscribers/revenue → agency has admin access

That's a very clean client-services architecture.

The downside is that multi-client agency management isn't as native as beehiiv's multi-publication model. You'd generally be managing separate Ghost sites/publications rather than treating your whole client portfolio as one publishing operation.

3. Kit — good if newsletters are part of a marketing funnel

Kit makes more sense when the newsletter is one component of a client's broader creator/marketing automation system—lead magnets, sequences, products, launches, etc.

I'd put it behind beehiiv/Ghost if the core product you're selling is specifically "we operate paid newsletters for multiple clients."

4. Substack — I'd avoid for an agency

Substack is excellent for an individual publisher who wants minimal operational complexity, but its model isn't particularly agency-friendly.

You want things like:

• client-specific ownership
• isolated subscriber databases
• agency/team permissions
• client-specific billing
• easy handoff when a contract ends
• multiple publications under an agency operating model

Those requirements point much more strongly toward beehiiv or Ghost.

The architecture I'd recommend

If you're building an actual agency operation, I'd structure it like this:

Agency
→ one internal agency/admin identity
→ separate workspace/account per client
→ client owns Stripe/billing
→ client owns publication + subscriber data
→ agency gets appropriate team permissions
→ agency manages editorial, analytics and growth

That is preferable to having one giant agency account with every client's subscribers and payments mixed together, even if the software technically supports it.

For example:

Client A

• beehiiv Workspace A
• Stripe Account A
• Newsletter A
• Subscribers A
• Agency = Admin/Member

Client B

• beehiiv Workspace B
• Stripe Account B
• Newsletter B
• Subscribers B
• Agency = Admin/Member

This gives you clean offboarding: if Client B leaves, you don't have to disentangle their subscribers, billing history and publication from everyone else.

My verdict

Choose beehiiv if your agency's primary need is efficiently operating many newsletters from a centralized team, particularly if you expect dozens of clients/publications.

Choose Ghost if your primary need is building subscription publications that should remain clearly owned and billed by each individual client.

If I were designing this specifically for a 5–50 client newsletter agency, I'd probably choose beehiiv with a separate workspace/account per client, plus a standardized agency onboarding/offboarding process. That gives you the operational advantages of beehiiv without creating a nasty client-ownership/billing problem later. www.beehiiv.comwww.beehiiv.com

If you mean an agency that operates paid newsletters for multiple client companies, with each client needing its own subscribers, payments, staff permissions, and ideally ownership, I’d shortlist these:

1. beehiiv — best overall for an agency

This is probably the closest fit.

• Multiple publications: you can run each client as a separate publication, with its own subscriber list, settings, domain, analytics, and monetization. www.beehiiv.com
• Granular access: users can be restricted to particular publications, rather than seeing every client's data. www.beehiiv.comwww.beehiiv.com
• Paid newsletters: supports multiple paid tiers and paywalled content. www.beehiiv.com
• Agency scaling: Enterprise is explicitly designed for organizations managing many publications, including 90+ publications. www.beehiiv.com
• Important billing caveat: if the client should own the billing account and publication, beehiiv recommends putting that client in their own account and adding your agency as a team member. www.beehiiv.com

Best setup: one beehiiv account/workspace per client when clients need independent ownership and billing; your agency gets invited access.

2. Ghost — best if each client needs a truly independent publication

Ghost is excellent for paid membership/newsletter businesses, but it's less convenient for an agency operating dozens of clients centrally.

Each Ghost publication can have multiple newsletters with separate subscription settings, and Ghost supports paid subscriptions through Stripe. ghost.org

The catch is significant: each independent Ghost(Pro) site requires its own Ghost(Pro) account/subscription. ghost.org

So I'd choose Ghost when client independence/ownership matters more than centralized agency operations.

3. Stripe Connect + a newsletter platform — best for a custom agency platform

If you're actually building an agency SaaS/platform, rather than just choosing software for your own agency, this is the architecture I'd investigate.

Stripe Connect is designed for platforms that manage payments for multiple businesses/connected accounts, and Stripe supports centralized management while keeping accounts separate. stripe.com

You could have:

Agency
→ Client A workspace → Client A Stripe account → Client A newsletter
→ Client B workspace → Client B Stripe account → Client B newsletter
→ Client C workspace → Client C Stripe account → Client C newsletter

That gives you a much cleaner separation of money, ownership, customer records, and permissions than trying to make one Stripe account serve every client.

My recommendation

Bottom line: For an agency managing clients today, I'd start with beehiiv, using one client = one publication/account when the client needs independent billing and ownership. Its current permission model is unusually well suited to separating agency staff by publication. www.beehiiv.comwww.beehiiv.com

If by “separate billing” you mean the agency charges each client a monthly management fee, rather than each client independently charging their newsletter subscribers, that's a different architecture—and I can recommend the best stack for that specifically.

If you're an agency running paid newsletters for multiple clients, I’d shortlist these:

1. beehiiv — best overall for an agency

This would be my first choice.

beehiiv explicitly supports agencies managing multiple client publications. One workspace can contain multiple publications, with each publication having its own subscriber list, settings, domain and analytics. Current limits are up to 3 publications on Launch/Scale, 10 on Max, and custom numbers on Enterprise. www.beehiiv.com

More importantly for your use case, you can either:

• Put multiple clients under your agency workspace, or
• Give each client their own beehiiv workspace/account and join it as a team member.

The latter is preferable when the client needs their own billing, login and ownership. www.beehiiv.com

For access control, beehiiv has publication-level and workspace-level roles, so you can give an editor access to Client A without exposing Client B. www.beehiiv.com

For the subscriber side, it supports multiple paid tiers, Stripe billing, paywalls, paid-only email/web content, and tier-specific access. beehiivhelp.zendesk.com

Best architecture:
Agency team → separate beehiiv workspace per client → client's Stripe account → client's publication

That keeps ownership and money cleanly separated while still letting your agency operate everything.

2. Ghost — best if you want maximum ownership/control

Ghost is particularly attractive if each client wants a more substantial publication/site rather than "just a newsletter."

Ghost has native memberships, paid subscriptions, member-only content, paid tiers and newsletters. Billing can connect directly to the client's Stripe account, with Ghost taking 0% of subscription revenue. ghost.orgdocs.ghost.org

Its access model is also strong: content can be public, members-only, paid-members-only, or restricted to particular tiers. ghost.orgdocs.ghost.org

Downside for an agency: it's less purpose-built around the "one agency, dozens of client publications" workflow than beehiiv. You'll generally manage each client's Ghost site separately.

3. Substack — easiest, but weakest for agencies

Substack allows multiple publications under one account, so you can switch between client publications from the dashboard. support.substack.com

But I wouldn't choose it for a serious agency operation where client ownership, granular staff permissions, separate billing and operational separation are important. It's optimized much more for individual publishers than agencies.

My recommendation

If your agency manages, say, 5–50 paid newsletters, I'd choose beehiiv.

I'd structure it like this:

Client → owns workspace + Stripe account
↓
Agency → invited as Admin/Member with only necessary permissions
↓
Publication → client's newsletter + subscriber database + paid tiers
↓
Stripe → client's billing/revenue

That gives you a clean separation between client data, subscriber access, payments and agency staff.

If you're expecting 50+ clients, or need things like white-label client portals, centralized agency billing, consolidated reporting across clients, client approval workflows, and one login for your operators, I'd look beyond newsletter-native platforms and consider an agency-oriented stack built around Stripe + a membership/auth layer + an email delivery platform. That can be substantially more flexible than trying to force one newsletter SaaS to behave like a multi-tenant agency platform.

If you tell me roughly how many clients you manage and whether clients need to log in themselves, I can narrow this down to the best 2–3 architectures.

For an agency managing multiple clients’ paid newsletters, I’d shortlist these:

My pick: beehiiv

For your exact use case, beehiiv is probably the best fit.

It explicitly supports agencies managing multiple client publications. You can either:

• Put multiple client publications in one workspace, with each publication having its own subscriber list, settings, domain and analytics; or
• Give each client their own beehiiv workspace/account, with the agency added as a team member. The latter is the better architecture when clients need their own login, billing, and ownership. www.beehiiv.com

Its current permissions are particularly useful for agencies: you can give someone access to only specific publications, rather than exposing every client's data. Roles include Admin, Member, and Contributor, with publication-level access. www.beehiiv.com

For larger agencies, beehiiv Enterprise is designed around multi-publication management and offers role-based permissions, portfolio analytics, and custom publication limits. www.beehiiv.com

Recommended setup:

Client A → Client A beehiiv workspace → Client A Stripe/billing
Client B → Client B beehiiv workspace → Client B Stripe/billing
Agency → invited into each workspace with appropriate permissions

That gives you clean billing separation + subscriber-data isolation + client ownership, while your agency can operate all the accounts.

Ghost is the better alternative if you need a full membership website

Ghost is particularly strong if each newsletter is really a paid publication/site, rather than just an email newsletter. It has native paid memberships, gated content, multiple tiers, and direct Stripe integration. Payments go directly to the publication's Stripe account and Ghost takes 0% transaction revenue. ghost.org

I'd choose Ghost when clients want things like:

• paid articles/archive
• member-only websites
• multiple subscription tiers
• custom websites
• full ownership of their Stripe/customer data

I wouldn't make Substack the agency standard

Substack does support multiple publications under one account, but its model is more oriented toward individual publishers than an agency operating a portfolio of client businesses. support.substack.com

Bottom line:
beehiiv for an agency operating many client newsletters; Ghost for agencies building full paid membership publications.

If you tell me roughly how many clients you manage (e.g. 5, 20, 100+) and whether each client needs to own/pay their own Stripe account, I can narrow this down to the best architecture and plan tier.