ChatGPT answers, unedited

If by “retargeting” you mean managing paid-retargeting campaigns across lots of client ad accounts, I’d separate the campaign-management/optimization tool from the agency reporting + billing layer.

Strong options

• smartly.io — geared toward agencies running multiple accounts, with centralized campaign management, media/creative workflows, and reporting. It requires appropriate admin access to each client ad account. Smartly Knowledge Base Smartly
• madgicx.com — particularly relevant if your retargeting is heavily Meta-focused. Its reporting can aggregate multiple ad accounts and channels, and it supports automated/white-labeled client reports. Madgicx Madgicx
• agencyanalytics.com — probably the more natural choice if your main pain is centralized agency reporting rather than campaign execution. It supports multiple data sources per client, white-label reporting, and portfolio-wide roll-up dashboards. Its current pricing is per client, with unlimited staff/client users and 85+ integrations on the advertised plan. AgencyAnalytics AgencyAnalytics Knowledge Base

The important distinction

If your requirements are specifically:

“50+ clients → dozens/hundreds of ad accounts → one agency login → centralized spend/campaign management → client-level reporting → consolidated agency reporting → one agency bill”

I'd look hardest at Smartly for the ad-operations layer, potentially paired with AgencyAnalytics for the client reporting layer. Smartly is designed around managing multiple client accounts, while AgencyAnalytics is explicitly built around organizing clients and aggregating their reporting. Smartly Knowledge Base AgencyAnalytics

If you tell me roughly how many clients/accounts you have (e.g. 20, 100, 500) and whether you're primarily Meta, Google, or both, I can narrow this to 2–3 platforms and compare centralized billing, account limits, white-labeling, reporting, and retargeting automation.

For an agency managing dozens of client retargeting accounts, AdRoll is worth a close look because its agency setup directly addresses the operational pieces you mentioned:

• Multi-client management: AdRoll says agencies can monitor performance, budgets, and campaign trends across client accounts from a single dashboard. AdRoll
• Centralized billing: Multiple advertiser profiles can be billed through one billing account and payment method, or split into separate billing accounts when clients need their own billing. AdRoll Help Center AdRoll Help Center
• Reporting: It supports automated/exportable reporting, reporting APIs, and cross-channel attribution, which can feed an agency's existing reporting stack. AdRoll AdRoll
• Actual retargeting: Website retargeting is a core capability, alongside display, native, video, social, and CTV. AdRoll Help Center AdRoll

adroll.com

How I'd narrow the choice

For your specific combination of dozens of accounts + centralized billing + reporting, AdRoll has unusually direct support for the workflow rather than requiring you to bolt those pieces together yourself. AdRoll Help Center AdRoll

If you tell me roughly how many clients, monthly ad spend, and whether clients pay you or the ad platform directly, I can compare AdRoll vs. StackAdapt vs. The Trade Desk vs. a white-label agency platform specifically for that operating model.

For an agency managing dozens of client accounts, with retargeting + centralized billing + cross-client reporting, I’d put these on the shortlist:

My pick: AdRoll

AdRoll is particularly aligned with what you described. It explicitly supports agencies managing multiple client accounts from a single dashboard, including campaign monitoring, budgets and trends. AdRoll

More importantly for your requirements, AdRoll now has multiple Billing Accounts, letting agencies associate different advertiser profiles with billing accounts and manage payment methods, invoices, plans and usage centrally. AdRoll Help Center AdRoll Help Center

It also provides cross-channel reporting and can bring in data from platforms such as Meta, TikTok, Google Ads, Amazon Ads, LinkedIn and others. AdRoll Help Center

adroll.com

When I'd look at Marin instead

Marin Software makes more sense if you're building an agency operating system for hundreds/thousands of accounts, rather than primarily wanting a retargeting platform.

Marin specifically advertises unlimited client-account structures, client groups, cross-brand reporting, customizable dashboards, automated reports and the ability to manage hundreds or thousands of smaller spenders. Marin Software Marin Software

Its reporting is especially agency-oriented: reports can run across multiple Marin accounts and be scheduled daily, weekly or monthly. Marin Software

marinsoftware.com

So, if your core requirement is:
"Give my team one place to run retargeting for 20–100+ clients, consolidate billing, and produce client reports" → I'd investigate AdRoll first.

If your requirement is instead "We manage huge numbers of accounts across Google/Meta/etc. and need an enterprise-grade management/reporting layer" → investigate Marin.

If you tell me roughly how many clients, monthly ad spend, and whether you're mainly Meta/Google or web-display retargeting, I can narrow this to 2–3 platforms and compare actual pricing/billing structure, account limits, reporting, white-labeling, and margin/rebate options.

If your priority is retargeting across dozens of client accounts + centralized agency operations, I’d shortlist these:

My pick: AdRoll if retargeting is the core service

AdRoll explicitly supports agencies managing multiple client accounts from one dashboard, with centralized monitoring of performance, budgets and campaign trends. It also supports display, native, video, social and CTV, with cross-channel reporting and attribution. AdRoll AdRoll

For an agency whose main product is something like "we run and optimize retargeting for 30–100 SMB/ecommerce clients," I'd investigate AdRoll first.

But Choozle is worth a serious look

If by "centralized billing" you mean one agency organization with many advertiser accounts and centralized payment controls, Choozle is particularly interesting. Its organization structure lets you manage unlimited advertiser accounts, with accounts able to inherit the organization's default payment method or use their own. It also provides organization-level and advertiser-level billing. Choozle Help Center choozle

That's potentially a better operational fit if your agency actually pays the media bills and then invoices clients.

If you're bigger/more sophisticated

Basis is probably the strongest option if retargeting is only one component of a broader media operation. It combines planning, programmatic, social, search, reporting and billing/reconciliation, specifically targeting agencies managing many clients. Basis Basis

StackAdapt is my choice when you have experienced programmatic traders and want deeper control and scale rather than the simplest retargeting workflow. It's heavily agency-oriented and supports display, video, CTV, audio, native, DOOH and other channels. StackAdapt StackAdapt

Bottom line:

• Mostly retargeting/ecommerce clients → AdRoll
• Dozens of advertisers + centralized account/payment administration → Choozle
• Full-service agency + billing/reconciliation across channels → Basis
• Large, sophisticated programmatic operation → StackAdapt

If you tell me roughly how many clients, average monthly ad spend/client, and whether your agency pays the ad bills or clients pay directly, I can narrow this to the best 1–2 options.

AdRoll explicitly supports agencies managing multiple client accounts from one dashboard, with centralized monitoring of performance, budgets and campaign trends. It also supports display, native, video, social and CTV, with cross-channel reporting and attribution. AdRoll AdRoll

For an agency whose main product is something like "we run and optimize retargeting for 30–100 SMB/ecommerce clients," I'd investigate AdRoll first.

But Choozle is worth a serious look

If by "centralized billing" you mean one agency organization with many advertiser accounts and centralized payment controls, Choozle is particularly interesting. Its organization structure lets you manage unlimited advertiser accounts, with accounts able to inherit the organization's default payment method or use their own. It also provides organization-level and advertiser-level billing. Choozle Help Center choozle

That's potentially a better operational fit if your agency actually pays the media bills and then invoices clients.

If you're bigger/more sophisticated

Basis is probably the strongest option if retargeting is only one component of a broader media operation. It combines planning, programmatic, social, search, reporting and billing/reconciliation, specifically targeting agencies managing many clients. basis.com basis.com

StackAdapt is my choice when you have experienced programmatic traders and want deeper control and scale rather than the simplest retargeting workflow. It's heavily agency-oriented and supports display, video, CTV, audio, native, DOOH and other channels.

Bottom line:

If your priority is one agency platform for dozens of client retargeting accounts, centralized billing, and consolidated reporting, I’d shortlist these:

1. AdRoll — best overall fit

• Built specifically for agencies managing multiple client accounts.
• Single dashboard across clients, automated reporting, campaign/budget monitoring.
• Supports centralized billing accounts, including agency/client setups. AdRoll Help Center AdRoll
• Strong retargeting plus display, native, video, social, and CTV.
• Particularly attractive if your clients are mostly SMB/mid-market or ecommerce.
• StackAdapt — best for sophisticated programmatic agencies

• Better choice if you're doing substantial programmatic buying and need deeper inventory, targeting, and media-trading capabilities.
• More enterprise/DSP-oriented than AdRoll. AdRoll
• I'd favor it for an agency with experienced media buyers and larger budgets.
• Choozle — best for data/control

• More geared toward agencies that want control over audience strategy, activation, measurement, and cross-channel governance. choozle
• Worth considering if your retargeting operation is data-heavy rather than simply "launch campaigns for 50 clients."

My pick

For the specific combination you described: AdRoll.

The important distinction is that you're not merely looking for a retargeting ad network—you need an agency operating layer. AdRoll explicitly supports multi-client management, centralized billing, reporting, and agency workflows. AdRoll Help Center AdRoll

If you're managing 50–100+ clients, I'd also evaluate the economics carefully: platform fee, minimum spend, agency rebate/discount, whether billing can be consolidated while maintaining client-level invoices, and whether reports can be fully white-labeled.

If you tell me roughly how many clients, monthly ad spend, and whether they're mostly ecommerce or lead-gen, I can narrow this to the best 2–3 options and compare pricing, white-label reporting, billing, client permissions, and retargeting capabilities.

For an agency managing dozens of client retargeting accounts, you usually want something that handles:

• multi-client account management
• centralized billing or spend visibility
• cross-client reporting dashboards
• team permissions
• white-label client reports
• integrations with Meta, Google, TikTok, LinkedIn, DSPs, etc.

The best fit depends on whether you mean running retargeting campaigns directly or managing reporting/billing around ad platforms.

Strong options

If centralized billing is the priority

Many ad platforms themselves are better for account hierarchy than third-party tools:

• Google Ads Manager Accounts (MCC) are commonly used by agencies to manage many advertiser accounts.
• Meta Business Suite / Business Manager structures allow agencies to manage client assets and permissions.

For actual one invoice covering many client ad accounts, enterprise platforms and agency partnerships are usually more likely to support it than basic reporting tools. Some agency-focused platforms advertise consolidated billing and multi-client workspaces. Influentials

My shortlist by agency size

Small–mid agency (5–50 clients)

• AgencyAnalytics for client reporting
• Google Ads Manager Accounts + Meta Business Suite for execution
• Add a data connector/reporting layer if clients need unified dashboards

Growth agency (50–500 clients)

• Smartly.io for social-heavy retargeting
• Skai for multi-channel paid media
• Singular for measurement/reporting infrastructure

Performance marketing / programmatic agency

• Choozle or a DSP with agency seat structures

A few questions would narrow this down:

1. Are you mainly retargeting on Meta, Google Display/YouTube, TikTok, or programmatic display?
2. Do you need the tool to buy/manage ads, or just report + invoice clients?
3. Roughly how many client accounts (20, 100, 1,000+)?

For an agency managing dozens of client retargeting accounts, the best tool depends on whether you mean paid social/search retargeting (Meta, Google, LinkedIn), programmatic display/CTV, or reporting + billing operations. For the specific requirements of centralized client management, billing, and reporting, these are the strongest categories:

If I were choosing by agency type:

1. Performance marketing agency (10–100+ clients, Meta/Google retargeting):

• Use Meta Business Manager + Google Ads Manager Accounts for execution.
• Add AgencyAnalytics or Looker Studio + connectors for client reporting.
• Add a billing layer (Stripe, QuickBooks, etc.) if clients are invoiced separately.

2. Programmatic retargeting agency:

• Look at Basis Technologies, The Trade Desk, or similar DSPs.
• These are better suited than standard ad managers when you need audience pools, frequency controls, inventory access, and consolidated media buying.

3. Agency that wants one login, one invoice, many clients:

• Prioritize platforms with agency hierarchies, sub-accounts, and consolidated billing. Some agency-focused platforms advertise features like centralized dashboards, client-level reporting, and unified billing models. kartra.com

My shortlist for a typical retargeting agency:

1. Skai — best all-around cross-channel enterprise option
2. Basis Technologies — best if you run serious programmatic retargeting
3. Smartly.io — best for social-heavy agencies
4. AgencyAnalytics — best reporting add-on
5. Singular — best if attribution and ROAS proof are the priority www.singular.net

A key question: are you mainly retargeting through Meta/Instagram + Google Display, or are you buying programmatic inventory (display/CTV/native)? The recommended stack changes quite a bit.

If you mean retargeting across many client ad accounts, with the agency needing centralized billing + cross-client reporting, I’d shortlist these:

1. business.google.com — best if most of your retargeting is Google

• Manage many client accounts from one login/dashboard.
• Cross-account reporting and performance comparison.
• Consolidated billing/monthly invoicing is supported.
• Strong access-control features for agency teams. Google Google

My pick for: agencies primarily running Google Display/YouTube/remarketing.

2. marinsoftware.com — best for a true multi-client agency operating layer

• Built specifically around managing lots of client accounts.
• Cross-client reporting, dashboards, alerts, automated reports, and bulk campaign management.
• Supports very large numbers of client accounts and multiple publishers/channels. Marin Software Marin Software
• Its multi-client reporting can roll multiple advertisers into a single report. Marin Support

My pick for: an agency that wants one operational/reporting layer rather than living separately inside each ad platform.

3. choozle.com — worth considering if retargeting is heavily programmatic

• Designed around audience targeting, including retargeting, cross-device targeting, CRM onboarding, and programmatic activation.
• Lets an organization manage multiple advertiser accounts under one organization account.
• Particularly interesting for centralized agency payment administration: advertiser accounts can have separate payment methods or inherit the organization-level card. choozle choozle
• skai.io — enterprise option

• Centralizes media data and workflows across channels.
• Strong reporting, scheduled reports, dashboards, and audience management across platforms such as Meta, TikTok and Snap. Skai Skai
• I'd consider it if you're operating at substantial enterprise/agency scale rather than just needing account management.

What I'd choose

One important distinction: centralized management/reporting and centralized billing aren't necessarily the same thing. If your requirement is specifically “one agency payment method pays for dozens of clients while clients remain logically separated, with automated client-level reporting/invoicing”, I'd evaluate the billing architecture first. Google explicitly supports consolidated billing, while Marin is stronger as the cross-client management/reporting layer. Google Marin Software

If you tell me whether you're primarily running Meta, Google, TikTok, or programmatic, and roughly how many client accounts (20 / 100 / 500+), I can narrow this to the best 2–3 options.

If your priority is retargeting/programmatic across dozens of client accounts + centralized billing + agency-wide reporting, I’d shortlist these:

• Choozle — best fit for a pure retargeting/programmatic agency. You can manage unlimited advertiser accounts under one organization, use organization-level billing/payment methods, and get centralized analytics/reporting. It explicitly supports separate advertiser billing while allowing accounts to inherit the agency payment method. choozle Choozle Help choozle

choozle.com

• Basis Technologies — best if you want an all-in-one agency media platform. It combines programmatic, paid social, search, direct buying, reporting, and billing/reconciliation rather than just retargeting. That's particularly compelling if your agency wants to consolidate its entire media workflow. Basis

basis.com

• StackAdapt — best for sophisticated programmatic execution. Strong targeting, optimization, cross-channel reporting, and agency adoption, but I'd investigate its specific agency billing/account hierarchy if centralized billing is a must-have rather than simply centralized campaign management. StackAdapt StackAdapt

stackadapt.com

• GrowthChannel — interesting if you want an agency-branded layer over multiple DSPs. It supports multi-client campaign silos, centralized reporting, role-based permissions and white-label client dashboards, while providing access to DSPs including DV360, The Trade Desk, StackAdapt and Basis. Growth Channel

growthchannel.com

My pick

For "dozens of clients, mostly retargeting, one agency operation, centralized billing/reporting", I'd start with Choozle.

For "we want to consolidate essentially all paid media into one agency operating system", I'd start with Basis.

For "we're a sophisticated programmatic shop and care more about DSP capabilities than billing", I'd look at StackAdapt or The Trade Desk.

If you tell me roughly how many clients, monthly ad spend, and whether the retargeting is mainly Meta/Google or open-web display/CTV, I can narrow this to the best 2–3 and compare pricing, account structure, billing, white-label reporting, and margins.

If you mean an agency running retargeting for dozens of separate clients, I’d shortlist these:

My pick: AdRoll

For your specific use case, AdRoll is probably the best starting point. It is explicitly built for agencies: you can manage multiple client accounts from one dashboard, monitor budgets/performance across clients, automate reporting, and run retargeting across display, social, video, mobile, native, and CTV. AdRoll AdRoll

It also offers an agency package with 14–20% rebates on committed ad spend, which can be relevant if you're managing substantial aggregate spend. AdRoll

adroll.com

If centralized billing is the most important requirement

I'd look closely at Google Ads Manager Accounts (MCC) if most of the retargeting is Google-based. Google specifically supports agencies managing many client accounts from one manager account, cross-account reporting, permissions, and linking a payments profile for monthly invoicing. Google Help

support.google.com

If you're talking 50–500+ clients

Then Marin Software becomes more compelling. Marin is designed around agency-scale account structures, cross-client reporting, automated dashboards, bulk campaign management, and even hundreds/thousands of smaller client accounts. Marin Software Marin Software

marinsoftware.com

Bottom line:

• Retargeting + easiest agency operation → AdRoll
• Google-heavy + centralized ad billing → Google Ads MCC
• Large agency + lots of publishers/clients + sophisticated reporting → Marin
• Enterprise cross-channel media management → Skai

One caveat: if by “centralized billing” you mean the agency pays all ad spend itself, then automatically invoices each client with markup, rather than simply having centralized account/payment administration, that's a different requirement. In that case I'd evaluate the billing infrastructure separately from the ad-management platform.

For your specific use case, AdRoll is probably the best starting point. It is explicitly built for agencies: you can manage multiple client accounts from one dashboard, monitor budgets/performance across clients, automate reporting, and run retargeting across display, social, video, mobile, native, and CTV. AdRoll AdRoll

It also offers an agency package with 14–20% rebates on committed ad spend, which can be relevant if you're managing substantial aggregate spend. AdRoll

adroll.com

If centralized billing is the most important requirement

I'd look closely at Google Ads Manager Accounts (MCC) if most of the retargeting is Google-based. Google specifically supports agencies managing many client accounts from one manager account, cross-account reporting, permissions, and linking a payments profile for monthly invoicing. support.google.com

support.google.com

If you're talking 50–500+ clients

Then Marin Software becomes more compelling. Marin is designed around agency-scale account structures, cross-client reporting, automated dashboards, bulk campaign management, and even hundreds/thousands of smaller client accounts.

If you mean paid-media retargeting across dozens of separate client advertisers, I’d shortlist these:

• choozle.com — best fit for your exact use case. It’s a self-service programmatic/DSP platform with retargeting, and its agency structure lets you manage multiple advertiser accounts under one organization. Accounts can inherit the organization’s payment method, while reporting/analytics are built in. choozle choozle Choozle Help
• stackadapt.com — best if you want a more enterprise-grade managed/programmatic operation. Strong cross-channel programmatic and centralized reporting, but I’d specifically confirm how their agency billing/account hierarchy works for your client setup. StackAdapt
• plai.io — worth considering if you want broader multi-channel ad management. It specifically advertises automation across client accounts, centralized reporting, white-label client access, and billing through Stripe. Plai

My pick

For 50+ clients where your agency wants to own the billing relationship and see everything centrally, I'd start with Choozle. Its account hierarchy is unusually relevant: you can have many advertiser accounts underneath an organization and either use separate payment methods or inherit the organization-level card. choozle

One caveat: if by "retargeting" you primarily mean Meta + Google remarketing, rather than display/programmatic retargeting, I'd choose differently. In that case, tell me which ad channels you need (Meta, Google, TikTok, LinkedIn, programmatic, etc.) and roughly how many clients, and I can give you a tighter 3-tool comparison.

If your priority is retargeting across dozens of client accounts + centralized agency operations, I’d put AdRoll at the top of the shortlist.

Best fit: AdRoll

adroll.com

Why it fits:

• Multi-client management: one dashboard for monitoring multiple client accounts.
• Retargeting-first DNA: strong display/native/video retargeting, with audience segmentation, frequency caps, and bidding controls.
• Centralized reporting: campaign and cross-channel reporting, with automated/exportable reports and reporting APIs. AdRoll AdRoll
• Agency economics: AdRoll specifically offers agency packages, including rebates tied to committed ad spend. AdRoll
• Broad channel coverage: display, native, video, CTV, and social integrations, rather than forcing you to manage everything separately. AdRoll

One caveat: if by "centralized billing" you mean one agency invoice that automatically consolidates media spend from every client, I'd verify the exact billing structure with AdRoll before committing. Their documentation clearly supports multiple billing profiles/accounts, but the agency billing model can differ from simply putting all client spend onto one invoice. RollWorks Help Center RollWorks Help Center

If billing is the #1 requirement

There are newer agency-oriented platforms that explicitly advertise consolidated invoicing + client-level accounts + rolled-up reporting, such as FluxIQ TV, although that's more specifically focused on CTV rather than being a general retargeting platform. FluxIQ TV

For a typical agency running 20–100+ clients across Google/Meta/display retargeting, I'd think about the stack this way:

If you tell me how many clients, approximate monthly ad spend, and whether you're mainly on Meta/Google/display/CTV, I can narrow this down to the 3 best platforms and compare their pricing, billing model, white-label reporting, and account limits.

If your priority is an agency managing dozens of client accounts with centralized billing + reporting, I’d shortlist Basis and AdRoll, with Basis as the stronger overall fit.

My pick: Basis

basis.com is particularly compelling if billing/reconciliation is as important as media buying. It combines programmatic, search, social, direct, CTV, reporting, and billing in one platform, including automated billing reconciliation. Its agency-oriented structure is explicitly designed for high client volumes. Basis Basis Basis

If retargeting is the main thing: AdRoll

adroll.com is arguably the cleaner choice if you're primarily selling retargeting/display/social/CTV rather than running a broad media-buying operation. It specifically offers a single dashboard for monitoring multiple client accounts, budgets and campaign trends, plus automated reporting. AdRoll

StackAdapt

stackadapt.com is excellent if your agency is programmatic-heavy and wants sophisticated targeting, CTV, native, audio, DOOH, etc. It is widely positioned toward agencies, but I'd put it behind Basis for your particular requirement because centralized financial/billing workflows appear to be a bigger differentiator for Basis. StackAdapt StackAdapt

Bottom line:

• 20–100+ client accounts + centralized billing/reconciliation: Basis
• Primarily retargeting/e-commerce clients: AdRoll
• Sophisticated programmatic trading team: StackAdapt
• Big enterprise + heavily Google ecosystem: DV360

If you tell me roughly how many clients, monthly ad spend, and whether you're billing clients on a % markup or flat fee, I can narrow this down to the best 2–3 options for your agency.

basis.com is particularly compelling if billing/reconciliation is as important as media buying. It combines programmatic, search, social, direct, CTV, reporting, and billing in one platform, including automated billing reconciliation. Its agency-oriented structure is explicitly designed for high client volumes. Basis Basis Basis

If retargeting is the main thing: AdRoll

adroll.com is arguably the cleaner choice if you're primarily selling retargeting/display/social/CTV rather than running a broad media-buying operation. It specifically offers a single dashboard for monitoring multiple client accounts, budgets and campaign trends, plus automated reporting. adroll.com

StackAdapt

stackadapt.com is excellent if your agency is programmatic-heavy and wants sophisticated targeting, CTV, native, audio, DOOH, etc. It is widely positioned toward agencies, but I'd put it behind Basis for your particular requirement because centralized financial/billing workflows appear to be a bigger differentiator for Basis.

Bottom line:

If your priority is managing dozens of client accounts with centralized billing + reporting, I’d shortlist these:

• Choozle — best fit for centralized agency operations. You can manage unlimited advertiser accounts under one organization, have accounts inherit an organization-level payment method, and use centralized analytics/dashboard reporting. It also supports retargeting and other programmatic channels. Choozle Help choozle choozle
• AdRoll — best if retargeting is the core use case. It explicitly supports multi-client management from a single dashboard, automated reporting, and cross-channel attribution. Its agency offering is particularly geared toward B2C/ecommerce retargeting. AdRoll AdRoll
• StackAdapt — best for a larger, programmatic-heavy agency. It's more enterprise/DSP-oriented, with sophisticated targeting, multi-channel buying, and real-time reporting. I'd favor it when you need display + CTV + video + audio rather than primarily straightforward retargeting. StackAdapt AdRoll

My pick

For 20–100+ client accounts where operational simplicity matters, I'd investigate Choozle first. The organization → advertiser-account structure and centralized/inherited billing are unusually aligned with your requirement. choozle Choozle Help

For an agency that's essentially selling “we'll run retargeting for you”, I'd lean AdRoll because its agency workflow and retargeting/attribution capabilities are more directly purpose-built for that model. AdRoll

If you tell me roughly how many clients, monthly ad spend, and whether you need Google/Meta + display or programmatic only, I can narrow this to the best 2–3 and compare billing, white-label reporting, margins, account limits, and API/automation.

If your agency is managing dozens of client accounts and the key requirements are retargeting + centralized billing + consolidated reporting, I’d shortlist these:

My pick: Choozle

For your exact description, Choozle is probably the closest fit. It lets an organization manage unlimited advertiser accounts, with advertiser-level payment methods or accounts inheriting the organization's default card. Choozle Help choozle

It also has native retargeting audiences, including site-visitor, campaign-engagement, and click-retargeting segments. Choozle Help

For agency reporting, Choozle provides organization-level dashboards across advertiser accounts, detailed campaign reports, scheduled reports, and an API that connects to tools such as AgencyAnalytics, NinjaCat, and TapClicks. Choozle Help

One caveat: Choozle is primarily a programmatic/DSP platform. Its current site says search and social integrations are managed-service only, so if your retargeting is primarily Meta Ads + Google Ads, I would lean toward ClientPlug instead. choozle

If you're mainly running Meta + Google

ClientPlug is worth looking at. It is specifically built around agency management, with a unified client roster, Meta Ads and Google Ads data, agency-wide reporting, and payment/billing visibility. ClientPlug ClientPlug

So, roughly:

• Programmatic display/retargeting across many clients → Choozle
• Meta + Google retargeting across many clients → ClientPlug
• Large enterprise, cross-channel media operation → Skai

If you tell me which channels you retarget on (Meta, Google Display, TikTok, programmatic, etc.) and roughly how many clients, I can narrow this to the best 2–3 options and compare pricing, margins/markup, white-label reporting, billing, and account limits.

For your exact description, Choozle is probably the closest fit. It lets an organization manage unlimited advertiser accounts, with advertiser-level payment methods or accounts inheriting the organization's default card. help.choozle.com choozle.com

It also has native retargeting audiences, including site-visitor, campaign-engagement, and click-retargeting segments. help.choozle.com

For agency reporting, Choozle provides organization-level dashboards across advertiser accounts, detailed campaign reports, scheduled reports, and an API that connects to tools such as AgencyAnalytics, NinjaCat, and TapClicks.

One caveat: Choozle is primarily a programmatic/DSP platform. Its current site says search and social integrations are managed-service only, so if your retargeting is primarily Meta Ads + Google Ads, I would lean toward ClientPlug instead.

If you're mainly running Meta + Google

If your main requirement is retargeting across dozens of client accounts + centralized billing + consolidated reporting, I’d put AdRoll at the top of the shortlist.

Best fits

1. AdRoll — best overall fit

AdRoll explicitly has an agency workflow for managing multiple client accounts from a single dashboard, including performance/budget monitoring and cross-channel reporting. It also supports multiple billing profiles/accounts, which is particularly relevant if you're managing dozens of advertisers. AdRoll Rollworks Help Rollworks Help

The big advantage is that retargeting is core to the product, rather than an incidental capability. You can run display, native, video, mobile, social and CTV while maintaining cross-channel attribution/reporting. AdRoll

adroll.com

2. Choozle — best if you're more DSP/programmatic-heavy

Choozle is attractive if your agency wants more control over audiences, programmatic buying and data. It supports advertiser accounts, detailed/pivot reporting and an API that can feed reporting platforms such as AgencyAnalytics, TapClicks and Funnel. Choozle Help Choozle Help

Its billing model is also agency-friendly: the platform describes unlimited advertiser accounts under one subscription, with monthly invoicing or prepaid funding options. Choozle Help

choozle.com

3. StackAdapt — best for larger/enterprise agencies

StackAdapt is the more heavyweight choice if you're looking beyond straightforward retargeting into sophisticated programmatic, omnichannel and first-party-data activation. Its reporting is highly customizable and combines campaign performance across programmatic and email. StackAdapt

stackadapt.com

My pick

For 20–100+ SMB/mid-market clients where retargeting is the primary service, I'd start with AdRoll.

For an agency where programmatic buying, audience/data control and API-based reporting are more important, I'd investigate Choozle.

One thing I'd clarify before signing: whether by "centralized billing" you mean one agency invoice for all media spend, or simply the ability to manage multiple billing accounts from one login. Those are materially different, and I'd verify the exact invoicing structure with sales. AdRoll does document centralized management of multiple billing accounts, but that isn't necessarily identical to one consolidated media invoice. Rollworks Help

If you mean an agency running retargeting/programmatic campaigns for dozens of separate clients, I’d shortlist these:

1. choozle.com — best fit for agency-owned programmatic

• Supports multiple advertiser accounts under one organization.
• Can use separate payment methods per advertiser or inherit the organization’s payment method.
• Built around audience targeting/programmatic activation and measurement. choozle choozle
• My pick if centralized account management + billing flexibility are the priority.
• marinsoftware.com — best for mature multi-client management/reporting

• Designed specifically for agencies managing large numbers of client accounts.
• Cross-client reporting, unified account management, automated reporting, dashboards, and bulk campaign operations. Marin Software Marin Software
• Better if you're managing multiple channels, not just retargeting.
• plai.io — best simpler agency-oriented option

• Central dashboard for multiple client accounts.
• Automated optimization, centralized reporting, white-label client access, and integrated billing.
• Particularly geared toward agencies running Meta and Google campaigns. Plai
• adbite.com — worth considering for programmatic-heavy agencies

• Unified multi-client dashboard, isolated client budgets, permissions, and agency-level management.
• Explicitly positioned for agencies ranging from 10 to 1,000 clients. Adbite

What I'd choose

One important distinction: centralized billing can mean either “one agency payment method pays for all client media” or “the platform generates consolidated invoices and lets me recharge clients.” Those are quite different requirements.

If you tell me which channels you need (Meta, Google, CTV, display/DSP, LinkedIn, etc.) and whether you want the agency to pay the media bill centrally, I can narrow this to the best 2–3 options.

For an agency managing dozens of client retargeting accounts, the best fit depends on whether you want to run retargeting campaigns, resell media, or mainly centralize reporting/billing. These are the strongest options:

If centralized billing is your #1 requirement

Look for an agency/reseller model rather than a normal advertiser account. Key features:

• One agency master account
• Separate client workspaces
• Client-level spend tracking
• Markups or management fees
• Consolidated invoices
• Role-based access for strategists and clients
• White-label reports

Platforms positioned specifically around agency operations, such as Ambit, emphasize multi-client management, reporting, spend pacing, and agency billing workflows. Ambit

My shortlist by agency type

• Small/mid-size performance agency (10–100 clients):

→ StackAdapt + AgencyAnalytics

• Agency selling “managed retargeting” as a packaged service:

→ AdRoll or Choozle

• Large agency with many channels and strict reporting requirements:

→ The Trade Desk + a reporting layer like Singular

• Need one dashboard for dozens of clients more than ad buying:

→ AgencyAnalytics or Singular

A couple of details would narrow this down a lot:

1. Are you mainly retargeting on Meta/Instagram, Google Display/YouTube, CTV, or programmatic display?
2. Do you need to charge clients through your own invoice (agency markup), or just have consolidated reporting while clients pay ad spend directly?

For an agency managing dozens of client retargeting accounts, I’d shortlist AdRoll and Choozle, with AdRoll probably the better fit if retargeting is the core use case.

My pick: AdRoll

adroll.com

AdRoll explicitly supports agencies managing multiple client accounts from a single dashboard, including campaign performance, budgets and trends. It also provides cross-channel reporting and attribution. AdRoll

The billing setup is particularly relevant to your requirement: AdRoll has a centralized Billing Accounts Management page specifically designed for agencies servicing multiple clients. AdRoll Help Center RollWorks Help

It also goes beyond basic display retargeting into display, native, video, social and CTV, so you can consolidate more of the retargeting stack rather than maintaining separate tools. AdRoll

When I'd choose Choozle instead

choozle.com

Choozle is compelling if your agency is more programmatic/DSP-oriented and wants greater control over audiences, data and activation. You can create unlimited advertiser accounts under an organization, while accounts can inherit the organization's payment method or use their own. Choozle Help choozle

Bottom line:

• 20–100+ SMB/ecommerce clients, primarily retargeting → AdRoll
• Programmatic-heavy agency with sophisticated audience/data needs → Choozle
• Large enterprise media-buying operation → StackAdapt

If you tell me roughly how many clients, monthly ad spend, and whether you need white-label client reports/invoicing, I can narrow this down to the best 2–3 options and compare their agency pricing.

adroll.com

AdRoll explicitly supports agencies managing multiple client accounts from a single dashboard, including campaign performance, budgets and trends. It also provides cross-channel reporting and attribution. AdRoll

The billing setup is particularly relevant to your requirement: AdRoll has a centralized Billing Accounts Management page specifically designed for agencies servicing multiple clients. help.adroll.com help.rollworks.com

It also goes beyond basic display retargeting into display, native, video, social and CTV, so you can consolidate more of the retargeting stack rather than maintaining separate tools. AdRoll

When I'd choose Choozle instead

If you mean an agency managing dozens of client ad accounts, especially Google + Meta, with one operational layer for billing and reporting, I’d shortlist these:

My recommendation

If Google Ads is the core of your retargeting: use business.google.com. It was explicitly designed for agencies managing multiple accounts and gives you centralized access, cross-account reporting, and consolidated billing. Google also supports using one billing setup across multiple client accounts and receiving a single monthly invoice. Google Google Help

If you're managing both Meta and Google and want the agency itself—not each ad platform—to be the central operating layer, I'd look hardest at clientplug.io. It currently positions itself around an agency-wide client roster, unified Meta + Google reporting, payment tracking, and an agency-level dashboard. ClientPlug

If billing is the really important part, there's an important distinction: a reporting/management platform isn't necessarily the entity that actually owns the ad-spend billing relationship. For example, Meta generally keeps billing at the individual ad-account level, whereas Google Manager Accounts can support consolidated invoicing. Google Help Blip

So if you tell me (1) Meta, Google, or both, (2) roughly how many client accounts, and (3) whether you want to pay the ad spend centrally and invoice clients yourself, I can give you a much tighter 2–3 tool recommendation.

If you mean retargeting/media buying across dozens of client ad accounts, with one agency-level view for management, billing, and reporting, I’d shortlist these:

My pick: Marin

For a traditional agency managing dozens or hundreds of advertisers, Marin is probably the strongest fit. It explicitly supports unlimited client accounts, cross-client reporting, automated reporting, budget pacing, and management across multiple publishers from one interface. Marin Software Marin Software

Its reporting layer can combine publisher spend with analytics/CRM data and produce client-specific or agency-wide dashboards. Marin Software

If centralized billing is the most important requirement

I'd look harder at Choozle. Its organization account can contain multiple advertiser accounts, with either separate payment methods per advertiser or accounts inheriting the organization's credit card. choozle It is particularly interesting if your "retargeting" means programmatic/display/CTV audience retargeting, rather than primarily Meta/Instagram retargeting.

One important distinction

If you're talking specifically about Meta retargeting, I'd separate campaign management/reporting from billing. Meta's native account structure generally keeps payment methods at the ad-account level, so a third-party reporting/management platform doesn't necessarily eliminate the underlying Meta billing architecture. Blip

So, in one sentence:

• Meta/Google + lots of clients + sophisticated agency reporting → Marin
• Programmatic retargeting + agency-level payment control → Choozle
• Huge enterprise, cross-channel operation → Skai

If you tell me whether you're running Meta, Google, programmatic/display, or all three, I can narrow this down to the best 2–3 options and compare pricing, billing model, white-label reporting, and account limits.

For a traditional agency managing dozens or hundreds of advertisers, Marin is probably the strongest fit. It explicitly supports unlimited client accounts, cross-client reporting, automated reporting, budget pacing, and management across multiple publishers from one interface. Marin Software Marin Software

Its reporting layer can combine publisher spend with analytics/CRM data and produce client-specific or agency-wide dashboards. Marin Software

If centralized billing is the most important requirement

I'd look harder at Choozle. Its organization account can contain multiple advertiser accounts, with either separate payment methods per advertiser or accounts inheriting the organization's credit card. choozle.com It is particularly interesting if your "retargeting" means programmatic/display/CTV audience retargeting, rather than primarily Meta/Instagram retargeting.

One important distinction

If you're talking specifically about Meta retargeting, I'd separate campaign management/reporting from billing. Meta's native account structure generally keeps payment methods at the ad-account level, so a third-party reporting/management platform doesn't necessarily eliminate the underlying Meta billing architecture.

So, in one sentence:

If you're talking about dozens of client ad accounts, especially across Google/Meta and with retargeting, I’d shortlist these:

• Marin Software — probably the strongest fit for a serious performance agency. It supports unlimited client accounts, cross-client management, automated spend/budget pacing, cross-platform reporting, dashboards, and bulk campaign management. Marin Software Marin Software
• Skai — better if you're an enterprise-scale agency managing many channels. It centralizes campaigns across 100+ publishers and provides centralized spend/performance reporting and automated optimization. Skai
• Adzooma — a more approachable option for smaller/mid-sized agencies. It has a unified dashboard, client grouping, bulk changes, and client-ready reporting across Google, Microsoft, and Meta. Adzooma
• Coupler.io — worth considering if the main pain is centralized reporting, rather than campaign execution. It can standardize dashboards across your client roster and automate data refreshes. Coupler.io

My pick

For your specific combination of retargeting + dozens of accounts + centralized management + reporting, I'd start with Marin. Its agency setup is explicitly designed around managing large numbers of client accounts, with cross-client reporting and centralized campaign/budget workflows. Marin Software

One caveat: "centralized billing" can mean two different things. If you mean one agency invoice/subscription for the management software, these platforms can fit. If you mean the agency pays the actual Meta/Google media spend for all clients from one billing account, that's a different requirement and dramatically narrows the options.

If you tell me whether you're managing Google Ads, Meta Ads, or both, and roughly how many client accounts / monthly ad spend, I can narrow this to the best 2–3 options.

For an agency managing dozens of client retargeting accounts, the best tool depends on whether you mean retargeting execution (DSP/social ads), cross-client reporting, or billing consolidation. The strongest fits are usually agency-oriented platforms rather than a single ad account manager.

Here are good options:

For centralized billing + many client accounts, look especially at platforms with an agency hierarchy:

• StackAdapt — good if you are actually buying media/programmatic retargeting at scale.
• Basis Technologies — stronger if you need operational controls, finance workflows, and enterprise agency processes.
• The Trade Desk — best for larger agencies with significant spend and sophisticated audiences.
• AgencyAnalytics or similar reporting layers — useful if your biggest pain is client dashboards rather than media buying. clientplug.io

If you want an all-in-one agency operating model (one login, multiple clients, white-label reports, consolidated billing), some newer agency-focused ad platforms emphasize those workflows. For example, Adbite markets multi-client dashboards, white-label reporting, and consolidated billing for agencies. adbite.com

A practical stack many agencies use:

1. Media buying: StackAdapt / The Trade Desk / Basis
2. Client reporting: AgencyAnalytics / Looker Studio / Supermetrics
3. Billing + margins: agency finance system or the DSP’s agency billing tools

A few questions would narrow it down:

• Are you mainly retargeting on Meta/Instagram + Google Display, or programmatic display/CTV?
• Roughly how many clients (20, 100, 500+)?
• Do clients pay you a management fee, media spend markup, or both?

For an agency managing dozens of client accounts, especially if retargeting is the core use case, I’d shortlist these:

• adroll.com — best fit for straightforward agency retargeting. It explicitly supports multi-client management from one dashboard, automated reporting, and display/video/social/CTV retargeting. AdRoll says 475+ agencies use it. AdRoll AdRoll
• marinsoftware.com — best for sophisticated multi-account operations. It supports unlimited client-account linking, cross-client reporting, budget pacing/allocation, automated workflows, and display retargeting across publishers such as Google, Criteo, and Yahoo DSP. Marin Software Marin Software Marin Software
• skai.io — best for enterprise agencies. It centralizes campaigns across 100+ publishers and provides centralized spend/performance management, but it's likely overkill if you're primarily doing retargeting. Skai

My pick

AdRoll if your priority is retargeting + easy multi-client management + reporting.

Marin if your priority is running an agency media operation at scale, where you need centralized account management, budget pacing, cross-client reporting, and automation across multiple ad platforms.

One caveat: centralized reporting/billing aren't necessarily the same thing. If by "centralized billing" you mean the agency pays one consolidated invoice and then allocates costs to each client, that's an important requirement I'd verify with the vendors before choosing.

If you tell me roughly how many clients, monthly ad spend, and whether you're managing Google/Meta/Criteo/etc., I can narrow this to the 2–3 best options.

For an agency managing dozens of client retargeting accounts, I’d put AdRoll at the top of the shortlist.

AdRoll for Agencies

Why AdRoll fits your use case

AdRoll explicitly positions the platform for agencies and says you can monitor performance, budget fulfillment and campaign trends across all client accounts from one dashboard. www.adroll.com

The billing structure is particularly relevant: multiple advertiser profiles can be billed under one billing account/payment method, or you can maintain separate billing accounts for different profiles/groups. help.adroll.com

For reporting, AdRoll offers exportable scheduled reports and reporting APIs, while its cross-channel attribution product can consolidate data from platforms such as Meta, TikTok, Google Ads, Amazon Ads, Microsoft Ads, etc. www.adroll.com

One alternative worth considering

Marin is stronger if your agency is less "retargeting-first" and more of a large paid-media management operation. It supports unlimited client accounts, cross-brand reporting, automated reporting, bulk campaign management, and custom workflows/scripts. www.marinsoftware.com

My pick:

• AdRoll → best fit for dozens of clients + retargeting + centralized billing/reporting.
• Marin → better if you're managing lots of Google/Microsoft/search campaigns alongside retargeting.

If you tell me roughly how many clients, monthly ad spend, and whether clients pay you or the ad platform directly, I can narrow this down to 2–3 platforms and compare their agency billing models.

For an agency managing dozens of client retargeting accounts, the best tool depends on whether you mean campaign execution, reporting, billing, or an all-in-one agency operating layer. There usually isn’t one perfect platform; many agencies combine a media management tool + reporting layer. adlibrary.com

Here are the strongest options:

If your priority is centralized billing + reporting

I’d look at:

1. Google Ads Manager Account (MCC) for Google retargeting/search/display clients — it’s the native backbone. Keywordme
2. AgencyAnalytics for polished client-facing dashboards. ClientPlug
3. Singular if you need serious attribution across channels and large spend volumes. Singular

If your priority is actually running retargeting campaigns at scale

A common agency stack is:

• Meta Business Manager + Google MCC → ownership/access structure
• Revealbot or Smartly.io → automation and optimization
• AgencyAnalytics or Singular → reporting layer
• Accounting/invoicing system → billing reconciliation

For a typical performance marketing agency (10–100 clients)

My shortlist would be:

• Small/mid agency: Revealbot + AgencyAnalytics
• Meta-heavy ecommerce retargeting: Madgicx + AgencyAnalytics
• Enterprise agency: Smartly.io + Singular
• Mobile/app acquisition agency: Singular

One thing to clarify: when you say centralized billing, do you mean:

1. the agency pays ad spend and invoices clients,
2. each client keeps their own payment method but you need consolidated reporting, or
3. you want a reseller-style ad account model with one wallet/invoice?

That changes the recommendation quite a bit.

If your key requirement is dozens of client accounts + retargeting + centralized billing + agency-wide reporting, I’d shortlist these:

• clientplug.io — best overall fit for agency operations. It combines Meta/Google account management, client payment tracking, campaign monitoring, and automated branded reporting in one dashboard. It explicitly supports an agency-wide rollup and per-client views. ClientPlug ClientPlug
• walledgardenhq.com — strongest if you're primarily doing Meta/Facebook retargeting. Its agency platform emphasizes unlimited client campaigns, centralized client management, automatic reporting, and cards-on-file/auto-billing. Walled Garden
• alpomi.com — strongest for cross-channel paid media. It puts Google, Meta, TikTok, and LinkedIn accounts into one workspace with portfolio-level performance, budget pacing, and white-label reports. Its current agency tier is aimed at multi-client PPC teams. Alpomi
• singular.net — best if attribution/reporting is the sophisticated part of your problem. It is designed for agencies managing many accounts and provides multi-account dashboards, client-level cost aggregation, permissions, and scalable reporting infrastructure. Singular

My pick

For a performance/retargeting agency, I'd start with ClientPlug if centralized billing + client management + reporting are equally important.

If what you really mean is "I want one platform where my agency can actually buy/manage retargeting media for 50+ clients and bill clients centrally", I'd look more closely at Walled Garden or a dedicated programmatic/retargeting platform, because ordinary reporting dashboards don't necessarily centralize the media buying and billing itself.

If you tell me whether you're mainly running Meta retargeting, Google Display/YouTube, or programmatic retargeting, I can narrow this to the 3 best platforms for your exact agency model, including pricing and account limits.

If you mean dozens of client ad accounts, especially Meta retargeting, I’d shortlist these:

My pick: Madgicx

For an agency running 20–100+ Meta accounts, Madgicx is probably the closest fit if your priority is actually managing ads + centralized visibility + reporting, rather than just building reports.

It can connect multiple Meta and Google accounts and aggregate them into dashboards/reports. Its agency-oriented workspace also handles connected accounts, team members, subscription and payment information centrally. academy.madgicx.com

Its reporting can combine Meta, Google Ads, TikTok, GA4, Shopify and Klaviyo, which is useful if you want each client's retargeting performance tied back to revenue rather than just ad metrics. academy.madgicx.com

One caveat: Madgicx is much more Meta-centric for actual campaign management; Google Ads support is primarily reporting/analytics rather than full campaign manipulation. academy.madgicx.com

If your biggest problem is automation

I'd look at Revealbot instead. If you have standardized rules like:

• retargeting campaign CPA > $X → reduce budget
• ROAS < X → pause
• frequency > X → flag/notify
• automatically adjust budgets across dozens of accounts

then a rules/automation-first platform can be better than a reporting-first tool. A recent 2026 comparison specifically ranks Revealbot highly for cross-account automation. wevion.ai

If by "centralized billing" you mean the agency pays Meta/Google on behalf of every client

That's an important distinction. Most SaaS ad-management tools don't actually consolidate the underlying media invoices from Meta/Google into one agency bill. They centralize the software subscription, account access, and reporting.

If that's what you're trying to accomplish—one agency payment method → dozens of client ad accounts → client-level spend allocation/invoicing/reporting—tell me that, because I'd recommend a somewhat different stack.

For an agency managing dozens of client retargeting accounts, you usually want a tool that handles multi-account access, centralized reporting, permissions, and billing/spend visibility rather than a normal ad manager. The best fit depends on whether you mean campaign execution or reporting/operations.

For retargeting specifically (Meta Pixel/CAPI, Google remarketing, audience management), I’d usually split the stack:

• Campaign execution: Meta Business Manager + Google Ads Manager (with agency manager accounts)
• Optimization/automation: Smartly.io, Skai, or similar enterprise platforms
• Client reporting: AgencyAnalytics or Singular
• Billing/spend controls: agency billing features inside the ad platforms, or a dedicated spend-management layer

If you need one dashboard where an agency owner can see 50+ clients, monitor spend, send reports, and track billing, look at agency-focused platforms such as ClientPlug, which combines ad performance views, reporting, and payment tracking. clientplug.io

A quick rule of thumb:

• 5–50 clients: AgencyAnalytics + native ad platform manager accounts is often enough.
• 50–500 clients: Smartly.io / Skai / Singular-style infrastructure becomes more attractive.
• Heavy retargeting + ecommerce: prioritize audience syncing, creative testing, attribution, and feed/catalog integrations over just reporting.

If you tell me whether your clients are mostly Meta retargeting, Google Display/YouTube, TikTok, or ecommerce catalogs, I can narrow this down.

If you mean dozens of client ad accounts, with retargeting execution plus centralized billing and client reporting, I’d shortlist these:

My pick: ClientPlug

For your specific combination—lots of clients + centralized billing + reporting—ClientPlug looks unusually aligned. It provides an agency-wide rollup and per-client views, connects Meta and Google Ads, and combines campaign performance with payment/client management in one system. clientplug.ioskai.io

ClientPlug

If retargeting automation is the priority

Revealbot is more compelling if you primarily want rules/automation across many Meta accounts—for example, automatically adjusting budgets, pausing poor performers, and running standardized retargeting workflows. Recent agency comparisons put it in the mid-market/multi-account category. hackceleration.com

If you're a big agency

Skai is the heavyweight option. It centralizes campaigns, spend, audiences and reporting across 100+ publishers/channels and supports scheduled/custom reporting. Its pricing is designed around larger programs rather than small agencies. skai.io

Skai

Bottom line:

• 10–50-ish clients, want billing + reporting + account management: ClientPlug
• 10–30 accounts, heavy automation: Revealbot
• 30+ accounts / enterprise spend / cross-channel: Skai or Smartly
• If by “centralized billing” you mean the agency pays the ad platforms centrally and then automatically charges each client, rather than merely tracking invoices, that changes my recommendation—I’d evaluate the billing architecture separately.

If retargeting is the core use case and you're managing dozens of client accounts, I’d shortlist these:

My pick: AdRoll

For actual retargeting, I'd start with AdRoll. It was built around retargeting and now supports display, native, video, social and CTV. Its agency product lets you monitor multiple client accounts from one dashboard, including performance and budgets, and provides cross-channel reporting/attribution. www.adroll.comwww.plai.io

AdRoll for Agencies

If centralized reporting/operations matter more: Marin

Marin Software is probably the stronger choice once you're talking about dozens to hundreds of accounts. It supports unlimited client accounts, client groups, cross-client reporting, shared dashboards, automated reports, and unified data across publishers. www.marinsoftware.com

Marin for Agencies

The catch: Marin is more of an enterprise advertising-management/optimization layer than a pure retargeting platform.

If centralized billing is the deciding factor: Plai

Plai is interesting because it explicitly combines multi-client ad management/reporting with integrated billing through Stripe, including charging clients by ad spend or subscription. www.plai.io

Plai for Agencies

So I'd rank them:

1. AdRoll — best if retargeting performance is #1.
2. Marin — best if you have a sophisticated agency operation with lots of accounts/channels.
3. Plai — best if billing + client management + reporting in one system is the priority.
4. Skai — worth considering for very large/enterprise agencies.

One important distinction: “centralized billing” can mean either one platform invoice that the agency pays, or actually invoicing/charging each client from the platform. Plai explicitly supports the latter; AdRoll/Marin's agency account structures don't necessarily mean they handle your client invoicing the same way. www.adroll.comwww.plai.io

If you tell me (1) Meta/Google/programmatic channels, (2) roughly how many clients, and (3) whether you need the tool to actually charge clients, I can narrow this to the best 2–3 options.

If your priority is retargeting execution + dozens of client ad accounts + centralized billing + client reporting, I’d shortlist these:

My pick: Plai

Plai for Agencies

Plai is unusually close to what you're describing: it lets agencies manage Facebook/Google campaigns across clients from one dashboard, apply automated optimizations across accounts, create white-labeled client access/reporting, and charge clients based on ad spend or subscription through integrated Stripe billing. www.plai.io

If by "retargeting" you mean actual display/native/CTV retargeting beyond Meta and Google, I'd look harder at Ambit. Its platform explicitly includes open-web retargeting and lets agencies run/resell media through an agency-level account, with the media automatically billed through Ambit. www.ambitads.com

Ambit

For a simpler agency operating system where billing and reporting matter more than sophisticated media buying, ClientPlug is also worth evaluating; it combines client/ad-account management, payment tracking, and unified Meta/Google reporting. clientplug.io

Bottom line:

• Meta + Google retargeting + agency billing: Plai
• True cross-channel/open-web retargeting + reselling media: Ambit
• Billing/client management first: ClientPlug
• Attribution/reporting first: RedTrack

If you tell me roughly how many accounts (e.g. 30, 100, 500), which ad networks (Meta/Google/TikTok/display), and whether you want to pay the ad platforms yourself and rebill clients, I can narrow this to the best 2–3 options and compare pricing/workflows.

If your priority is retargeting across dozens of client accounts + centralized billing + centralized reporting, I’d shortlist these:

My pick: Choozle

For the exact workflow you're describing, Choozle looks particularly well matched. You can create unlimited advertiser accounts under an organization, give accounts their own payment methods or inherit the organization's payment method, and use centralized analytics/reporting. help.choozle.com

That's useful if your agency wants something like:

Agency → 50 client accounts → separate campaigns/audiences → centralized payment → client-specific reporting

Choozle is also specifically a programmatic advertising platform, so it's a more natural fit if retargeting/display/RTB is the core service rather than primarily search PPC. choozle.com

When I'd choose Marin instead

If you're managing Google/Microsoft/search + social + other channels, and retargeting is just one part of a broader performance-marketing operation, I'd lean toward Marin. It supports unlimited client accounts, cross-client reporting, automated dashboards, bulk campaign management, and unified data across publishers. www.marinsoftware.comskai.io

Bottom line:

• Retargeting/programmatic agency → Choozle
• Large multi-channel performance agency → Marin
• Enterprise omnichannel → Skai
• Agency wanting built-in client billing/white-label workflow → Plai skai.io

If you tell me which channels you're retargeting on (Meta, Google Display, CTV, programmatic, etc.) and roughly how many clients, I can narrow this to the 2–3 best options and compare pricing/workflow.

If you mean paid-media/retargeting agencies managing dozens of client ad accounts, I’d shortlist these:

My pick: Smartly for a serious agency operation

Smartly is particularly compelling if you're managing dozens of accounts across Meta plus other channels. Its reporting can blend multiple ad accounts and channels, and it is built around centralized campaign management rather than simply being a reporting dashboard. www.g2.com

If you're primarily Meta/e-commerce: Madgicx

Madgicx is probably the better value-oriented choice. It supports multiple Meta/Google/TikTok accounts in unified dashboards, aggregation across accounts, automated client reports, and white-label reporting. madgicx.com

It also gives you a single workspace where you can manage connected ad accounts, team members, subscription and payment information. academy.madgicx.com

If centralized billing is the killer requirement

I'd look particularly closely at TapClicks or Smartly rather than choosing purely on ad-optimization features. You want to distinguish between:

• Centralized SaaS billing — agency pays one software bill.
• Centralized client ad-spend billing — agency funds/manages client media spend.
• Client-level invoicing/reconciliation — automatically attribute spend to Client A/B/C and generate invoices.
• Consolidated reporting — one agency view while keeping each client's data isolated.

Those are very different capabilities.

If you tell me roughly how many client accounts (e.g. 20, 50, 200), which networks (Meta only vs Meta + Google/TikTok), and whether by “centralized billing” you mean software billing or actually paying/rebilling the clients' ad spend, I can narrow it to the best 2–3 options.

If you mean paid retargeting across many Google/Meta/etc. client accounts, I’d shortlist these:

My pick: Marin

For an agency managing dozens or hundreds of client accounts, Marin is probably the closest fit. It lets you manage client accounts from a unified interface, perform cross-client reporting, automate campaign/budget workflows, and connect data from multiple publishers. Marin explicitly supports unlimited client accounts and cross-brand reporting. www.marinsoftware.com

Its reporting is particularly agency-friendly: you can create reports across multiple clients, automate delivery, and build client-specific dashboards. support.marinsoftware.com

Marin for Agencies

One caveat: "centralized billing" is different from centralized account management. Marin's public material emphasizes the latter, so I'd specifically ask sales whether they can put all client media/software charges on one agency invoice and then provide per-client cost allocation.

If centralized billing is non-negotiable, tell me whether you're talking about Google Ads, Meta Ads, or both and whether you want the agency to pay the ad spend itself and rebill clients. That changes which platform I'd recommend.

If you mean retargeting on Meta + Google across dozens of client accounts, I’d shortlist these:

My pick: Plai

For your exact requirements, Plai looks closest to an agency operating system. It supports automated optimizations across multiple client accounts, centralized reporting, white-labeled client access, and—importantly—lets agencies charge clients based on ad spend or recurring subscription through integrated Stripe billing. www.plai.io

If you're primarily concerned with performance management rather than invoicing, I'd look harder at Pace. It specifically supports campaign groups such as Prospecting and Retargeting, portfolio-level reporting across Google, Meta, TikTok, LinkedIn and Microsoft, automated pacing, and a single agency bill. paceads.com

For 50–100+ accounts, Singular becomes more compelling if attribution and cross-channel ROI are important. It has multi-account dashboards, client-level aggregation, permissions and customizable reporting, but it's more of a measurement/attribution platform than an agency billing system. www.singular.net

One caveat: “centralized billing” can mean two different things:

1. You pay the ad platforms centrally for all clients, or
2. You invoice/charge your clients centrally for media + management.

If you mean #1, I’d narrow the list substantially because most agency dashboards don't actually consolidate the underlying Meta/Google media billing. If you mean #2, Plai is probably the first one I'd demo.

For an agency managing dozens of client retargeting accounts, you usually want more than a campaign manager—you need multi-account access, centralized billing, permissions, client reporting, and ideally cross-client performance views.

The best fit depends on whether you’re mainly managing Meta retargeting, Google Ads remarketing, programmatic, or a mix:

My shortlist by agency size

1–20 client accounts

• Meta Business Manager + Google Ads Manager Accounts
• AgencyAnalytics for reporting
• Plai if you want more automation/workflow support www.plai.io

20–100+ client accounts

• Smartly.io (especially Meta/social-heavy)
• Skai (broader enterprise media buying)
• Singular (if attribution and portfolio reporting are the priority) www.singular.net

If centralized billing is the biggest requirement
Look for platforms with agency billing structures or partner programs. Some agency-focused platforms provide consolidated billing dashboards rather than forcing each client account to be handled separately. kartra.com

A common agency stack is:

• Ad platforms: Meta Business Manager + Google Ads Manager Accounts
• Execution/optimization layer: Smartly.io / Skai / Plai
• Reporting layer: AgencyAnalytics / Singular
• Billing: Stripe, agency invoicing software, or platform partner billing

If you mean retargeting specifically (dynamic product ads, audiences, pixels/CAPI, frequency control) rather than general paid media management, the recommendation changes.

For an agency managing dozens of client ad accounts, I’d shortlist MarinOne first.

Best fit: MarinOne

It’s particularly agency-oriented: you can manage multiple client accounts from one login, use cross-client reporting, automate recurring reports, and manage campaigns across publishers from a unified interface. Marin explicitly supports agencies with unlimited client accounts and client-level permissions. www.marinsoftware.com

For reporting specifically, Marin can aggregate data across clients and publishers, with customizable dashboards and automated client reporting. www.marinsoftware.com

Strong alternative: Skai

I'd look at Skai if you're running a more sophisticated omnichannel operation—paid search + paid social + retail media + display/CTV. It has centralized reporting, audience management, budget optimization, and automated reporting. skai.io

One caveat on “centralized billing”

If by centralized billing you mean the agency pays the ad platforms once and invoices clients itself, that's different from centralized campaign management/reporting. Neither Marin nor Skai appears to make agency media billing the core differentiator. I'd verify their current billing/account-ownership model during the sales process.

My ranking for your use case:

If you tell me whether your “retargeting” is primarily Meta + Google, programmatic/display, or all channels, I can narrow this down to the 2–3 platforms that actually make sense.

For your specific use case, AdRoll would be my first tool to evaluate.

AdRoll is unusually well aligned with agencies managing lots of client accounts:

• Multi-client management: agency users can monitor performance, budgets, and campaign trends across client accounts from a single dashboard. www.adroll.com
• Centralized billing: you can associate multiple advertiser profiles with the same billing account/payment method, or split them into separate billing accounts when needed. help.rollworks.com
• Reporting: scheduled/exportable reports plus reporting APIs make it easier to feed data into agency dashboards and client reporting. www.adroll.com
• Retargeting is a core capability: display, native, video, mobile, social, and CTV retargeting are supported. www.adroll.com
• Agency-specific program: AdRoll explicitly offers agency pricing/rebates and an agency package. www.adroll.com

AdRoll for Agencies

How I'd shortlist them

The important distinction is that AdRoll is much closer to an agency operating layer for retargeting, whereas Google/Meta primarily give you account-management structures around their own ecosystems.

If you're talking about 20–100+ clients, I would specifically compare AdRoll vs. StackAdapt based on whether you want easy agency operations or more sophisticated programmatic buying.