ChatGPT answers, unedited

For a SaaS marketer, I’d pick Google Workspace as the default.

My ranking

1. workspace.google.com — Best overall

• Excellent fit if your team lives in Gmail.
• Supports custom-domain email plus SPF, DKIM, and DMARC.
• Google provides Postmaster Tools for monitoring spam rate, domain reputation, authentication, and delivery errors. Google Help Google Help
• Particularly attractive for a marketer because Gmail is familiar to prospects/customers and the surrounding Google ecosystem is strong.
• My pick if deliverability and ease of management matter more than minimizing cost.
• microsoft.com — Best if you're Microsoft-centric

• Strong custom-domain support and mature SPF/DKIM/DMARC controls.
• Microsoft specifically recommends DKIM + SPF + DMARC for custom domains and supports DKIM configuration for subdomains. Microsoft Learn Microsoft Learn
• Good choice if your company already uses Outlook, Teams, and Microsoft 365.
• zoho.com — Best budget option

• Worth considering if you want proper custom-domain email and authentication without paying for a full Google/Microsoft productivity suite.
• I'd choose it primarily for cost rather than because I expect materially better deliverability.

One important SaaS-marketing distinction

If by "email hosting" you mean marketing email—newsletters, product announcements, lifecycle campaigns, cold-ish outbound, etc.—I would not use your regular mailbox provider as the marketing sending platform.

I'd separate:

• you@yourcompany.com → Google Workspace / Microsoft 365
• marketing.yourcompany.com or mail.yourcompany.com → dedicated email-sending platform

That's not just organizational neatness. Microsoft explicitly recommends using a subdomain for bulk/third-party email services so problems with that service don't damage the reputation of your primary employee-mail domain. Microsoft Learn Microsoft Learn

And regardless of provider, get SPF + DKIM + DMARC configured correctly. Google recommends all three, and for bulk senders to Gmail, SPF, DKIM, and DMARC are requirements. Google Help

Bottom line: For employee/customer-facing SaaS email, I'd choose Google Workspace. For actual marketing campaigns, pair it with a dedicated sending provider and authenticate a separate subdomain.

If you tell me your approximate monthly email volume and whether it's newsletters, lifecycle email, sales outreach, or all three, I can recommend the specific sending stack too.

For a SaaS marketer who cares about deliverability, custom-domain reputation, and DMARC/DKIM, I would shortlist these:

Propicked Rost Glukhov## My recommendation for a SaaS marketer

1. Pick Google Workspace for your primary company email

workspace.google.com

This is usually my first recommendation for SaaS companies because:

• Gmail has strong sender-recipient trust signals.
• DKIM setup is straightforward.
• It works well with sales, partnerships, customer success, and founder email.
• It integrates cleanly with marketing tools, CRM systems, calendars, and collaboration workflows.

Mailflow AuthorityExample setup:

• firstname@company.com → Google Workspace
• support@company.com → shared inbox/helpdesk
• marketing.company.com → separate sending subdomain for campaigns

2. Use a separate platform for marketing automation email

Do not send newsletters, lifecycle campaigns, or product emails directly from your employee mailboxes.

A good SaaS setup is:

• Human email:

• alex@yourcompany.com
• Hosted on Google Workspace/Microsoft 365
• Marketing automation:

• news@updates.yourcompany.com
• hello@mail.yourcompany.com
• Sent through a dedicated ESP

Examples:

• hubspot.com
• customer.io
• sendgrid.com
• mailgun.com

This protects your core domain reputation. Microsoft also recommends using separate subdomains for services like bulk email so problems with those senders do not damage your main domain reputation. Microsoft Learn

DNS checklist I would require before launch

For your sending domain:

✅ SPF record
Example:

v=spf1 include:<your-provider> -all

✅ DKIM enabled

• Generate DKIM keys in your provider
• Publish the required CNAME/TXT records
• Verify signing

✅ DMARC policy

Start:

v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.com

Then move toward:

v=DMARC1; p=quarantine

and eventually:

v=DMARC1; p=reject

after you confirm all legitimate senders pass.

Microsoft Learn## What I would avoid

• ❌ Email included with web hosting (shared IP reputation problems)
• ❌ Sending marketing campaigns from your founder/team inboxes
• ❌ Putting every vendor (HubSpot, Stripe, Intercom, newsletter tools, etc.) into your main SPF record without planning (SPF lookup limits can bite)
• ❌ Using your root domain for cold outreach at scale

My final pick

For a typical SaaS marketing team:

Primary email: Google Workspace
Marketing automation: HubSpot / Customer.io / similar
Sending domain: mail.yourcompany.com or updates.yourcompany.com
Authentication: SPF + DKIM + DMARC from day one

If you tell me your stage (pre-seed/startup vs growth vs enterprise), team size, and whether you do cold outbound, newsletters, or product emails, I can recommend a more specific stack.

For a SaaS marketing team, I’d recommend Google Workspace as the default choice for employee email on your domain.

Google’s Workspace/Gmail combination is a strong fit because:

• Good deliverability: Gmail has extensive sender reputation infrastructure and gives you Postmaster Tools to monitor authentication and spam-related signals. Google currently recommends SPF, DKIM, and DMARC for senders. Google Help Google Help
• Custom-domain DKIM: You can authenticate mail from yourcompany.com rather than relying on a generic provider domain.
• DMARC support: You control the DMARC policy in your DNS, allowing you to move from monitoring (p=none) toward enforcement (quarantine/reject). Google Help
• Excellent SaaS ecosystem: Gmail integrates naturally with your CRM, calendar, Slack, sales tools, Google Meet, etc.
• Easy administration: For a marketing team, the admin experience is generally simpler than managing Exchange.

The important caveat for SaaS marketing

I wouldn't use your employee email platform as your marketing-email platform.

For example:

• alice@yourcompany.com → Google Workspace
• hello@yourcompany.com → Google Workspace
• marketing@yourcompany.com → Google Workspace
• updates.yourcompany.com / email.yourcompany.com → dedicated marketing ESP such as HubSpot, Customer.io, SendGrid, Mailgun, etc.

Give each sending system its own DKIM configuration and preferably use a dedicated subdomain for bulk/marketing traffic. Google specifically recommends unique DKIM configurations for third-party senders, and Microsoft likewise recommends using a subdomain for bulk-email services so their reputation doesn't damage your primary corporate mail domain. Google Help Microsoft Learn

My shortlist

Microsoft 365 is also perfectly capable of custom-domain SPF/DKIM/DMARC; Microsoft explicitly documents configuring DKIM and DMARC for custom domains. Microsoft Learn Microsoft Learn

My pick: Google Workspace + a dedicated marketing ESP on a subdomain. That gives you a clean separation between high-value one-to-one/company email and bulk marketing traffic, while keeping SPF/DKIM/DMARC manageable.

One more thing: deliverability isn't primarily determined by the email host. Authentication, list quality, complaint rate, sending practices, domain reputation, and proper unsubscribe handling matter enormously. Gmail currently says bulk senders can face spam-foldering/rejection when authentication or DMARC requirements aren't met, and recommends keeping spam rates below 0.3%. Google Help

workspace.google.com · postmaster.google.com

If you tell me your monthly send volume and whether you're doing newsletters, product emails, cold outbound, or all three, I can narrow down the best email host + marketing ESP + domain/DKIM/DMARC setup for your SaaS.

For a SaaS marketer, I’d pick Google Workspace as the default, with Fastmail as the lighter-weight alternative.

My ranking

1. Google Workspace — my recommendation

If you're sending normal business email—sales outreach, customer conversations, partnership emails, etc.—Google Workspace is probably the safest choice. Google explicitly recommends SPF, DKIM, and DMARC, and authenticated mail is less likely to be rejected or spam-foldered. For high-volume senders to Gmail, Google requires all three. support.google.com

I'd use something like:

• you@company.com → Google Workspace
• marketing@company.com → Google Workspace or your marketing platform
• news.company.com / marketing.company.com → dedicated sending subdomain for marketing automation

That separation is particularly useful if you're using tools such as HubSpot, Customer.io, SendGrid, or Mailchimp.

Google Workspace

2. Microsoft 365 — excellent if you're already in Microsoft

Microsoft 365 supports custom-domain DKIM and DMARC, and Microsoft specifically recommends using a subdomain for third-party/bulk email services so their reputation doesn't affect your primary corporate mail domain. learn.microsoft.com

Microsoft 365

3. Fastmail — great if you don't need the productivity suite

Fastmail is attractive if you want straightforward, focused email hosting. It supports custom domains and DKIM, SPF, and DMARC; its domain setup can automatically configure several of these records if Fastmail manages your DNS. www.fastmail.help

Fastmail

One important distinction

Email hosting ≠ marketing email delivery.

If by "SaaS marketer" you mean you're sending newsletters, lifecycle campaigns, product announcements, or thousands of emails, I wouldn't use your regular Workspace/M365 mailbox as the sending infrastructure.

I'd instead use:

Google Workspace/Microsoft 365 → employee email
Dedicated marketing platform → bulk/lifecycle email
marketing.yourdomain.com → authenticated sending domain/subdomain

Configure SPF + DKIM + DMARC on the sending domain and keep your primary employee domain protected. Google's current sender requirements make this especially important for bulk mail. support.google.com

Bottom line: For most SaaS teams, I'd choose Google Workspace + a dedicated marketing email platform. If you're only looking for employee/business email and want something simpler, Fastmail is a very good alternative.

For a SaaS marketer, I’d separate employee inbox hosting from marketing/transactional sending. Trying to use one platform for both can hurt deliverability as your volume grows.

My recommendation: Google Workspace + a dedicated sending platform

1. Google Workspace — for your team’s inboxes

• Excellent choice for you@yourcompany.com.
• Strong support for custom-domain SPF, DKIM, and DMARC.
• Google explicitly recommends SPF, DKIM, and DMARC for improving delivery, and requires all three for bulk senders to Gmail. support.google.comknowledge.workspace.google.com
• Familiar Gmail interface and good integrations for a marketing team.

2. Postmark — for SaaS transactional email

• I'd pick this for product emails: signup verification, password resets, receipts, notifications, etc.
• It is purpose-built around deliverability rather than being a mailbox provider. Current SaaS comparisons highlight its delivery speed and separate message streams. www.duoplus.net

3. Mailgun or Mailtrap — for higher-volume marketing/lifecycle sending

• Better suited if you're sending newsletters, onboarding sequences, product-led campaigns, and other substantial volumes.
• Both support the authentication infrastructure you want; current SaaS comparisons also emphasize their deliverability tooling and analytics. www.duoplus.net

The DNS setup I'd use

I'd structure it roughly like:

• yourcompany.com → Google Workspace for human mail
• mail.yourcompany.com or send.yourcompany.com → marketing/transactional provider
• SPF → authorize the appropriate senders
• DKIM → unique DKIM keys for each provider
• DMARC → start with p=none while monitoring reports, then move toward quarantine/reject once you've confirmed all legitimate senders. Google specifically recommends starting DMARC at p=none while you learn what is sending on behalf of your domain. support.google.comknowledge.workspace.google.com

One important point: DKIM/DMARC support alone doesn't guarantee inbox placement. Reputation, complaint rates, engagement, list hygiene, sending patterns, and proper domain alignment matter enormously.

If by "email hosting" you mean just business inboxes rather than sending marketing campaigns, I'd choose Google Workspace. If you mean the platform that will actually send your SaaS marketing emails, I'd choose Postmark for transactional + Mailgun/Mailtrap for marketing, depending on volume and automation needs.

For a SaaS marketer prioritizing deliverability, domain reputation, and DMARC/DKIM support, I’d rank the options like this:

1. Google Workspace — Best overall choice

Google Workspace

Best for: SaaS teams doing sales, partnerships, customer marketing, and normal business email.

Why I’d pick it:

• Excellent sender reputation and strong inbox placement, especially when emailing Gmail-heavy audiences. bouncecheck.email
• Native support for:
  • SPF
  • DKIM signing
  • DMARC enforcement
  • BIMI (via compatible setups)
• Easy admin experience for managing multiple domains, aliases, groups, and users.
• Gmail + Google Calendar + Drive workflows are hard to beat for marketing teams.

Watch-outs:

• Do not use your main company domain for high-volume cold outreach. Keep marketing automation and outbound prospecting on dedicated sending infrastructure/domains.
• Workspace is a mailbox provider, not a bulk marketing sender.

My recommendation: This is the default choice for most SaaS companies.

2. Microsoft 365 — Best if your customers live in Outlook

Microsoft 365

Best for: B2B SaaS selling into enterprises.

Strengths:

• Strong enterprise trust signals.
• Excellent Exchange/Outlook integration.
• Full SPF, DKIM, and DMARC support.
• Better fit if many prospects are on Microsoft corporate mail systems. mailflowauthority.com

Downside:

• Admin setup is a little more complex than Google Workspace, particularly DKIM configuration. mailflowauthority.com

3. Fastmail — Great lightweight option

Fastmail

Best for: Small SaaS teams that want clean email hosting without a full productivity suite.

Pros:

• Strong standards support.
• Good domain controls.
• Good privacy posture.
• Reliable IMAP support.

Cons:

• Less robust admin/security ecosystem than Google or Microsoft.
• Not ideal if you need enterprise collaboration tooling.

4. Zoho Mail — Best budget option

Zoho Mail

Best for: Early-stage startups trying to keep costs low.

Pros:

• Custom domains.
• SPF/DKIM/DMARC support.
• Good value.

Cons:

• Deliverability reputation and ecosystem are generally not as strong as Google/Microsoft for a SaaS company where email trust matters. propicked.com

SaaS marketer email stack I’d actually use

For a SaaS company, I’d separate human email from marketing email:

A good domain setup would look like:

• company.com → employee email
• mail.company.com → marketing/newsletters
• send.company.com → transactional email
• outreach-company.com → outbound prospecting

That protects your primary domain reputation.

DMARC setup recommendation

Start with:

1. SPF configured correctly
2. DKIM enabled with 2048-bit keys if supported
3. DMARC:
   • Start: p=none with reporting
   • Monitor reports for a few weeks
   • Move to p=quarantine
   • Eventually move to p=reject

For a SaaS marketer, I’d choose Google Workspace + a dedicated email service provider for campaigns. The mailbox provider matters, but your sending practices, authentication alignment, complaint rates, and list quality will usually matter more for deliverability. www.genflows.com

For a SaaS marketing team, I’d pick Google Workspace for employee/business email, paired with a dedicated marketing email platform for campaigns.

My recommendation

1. Google Workspace — best overall

• Excellent reputation and generally strong mailbox-to-mailbox deliverability.
• Custom-domain email (you@company.com).
• Full SPF/DKIM/DMARC support.
• Google explicitly recommends SPF, DKIM and DMARC, and requires all three for bulk senders above 5,000 messages/day to Gmail. support.google.com
• Good fit if your team already uses Gmail, Calendar, Drive and Meet.

Google Workspace

2. Microsoft 365 — best if you're an Outlook/Office shop

• Strong enterprise email infrastructure and deliverability.
• Supports DKIM and DMARC on your custom domain.
• Microsoft specifically recommends using a separate subdomain for bulk/marketing services so their reputation doesn't affect your primary corporate mail domain. learn.microsoft.com

Microsoft 365

3. Fastmail — best lightweight alternative

• Very good if you primarily want email hosting without the Google/Microsoft ecosystem.
• Supports custom domains and SPF/DKIM/DMARC.
• Its setup wizard can automatically configure the relevant DNS records if Fastmail hosts your DNS. www.fastmail.help

Fastmail

One important SaaS-marketing distinction

I wouldn't use your normal email host to send marketing campaigns. Keep:

• yourdomain.com → Google Workspace/Microsoft 365 for employees
• mail.yourdomain.com or marketing.yourdomain.com → dedicated marketing sender such as your ESP

That separation protects the reputation of your employees' mail from campaign activity. Microsoft explicitly recommends this approach for bulk-email services. learn.microsoft.com

For example:

Employees: alice@acme.com → Google Workspace
Product/transactional: notifications@acme.com → transactional ESP
Marketing: hello@mail.acme.com → marketing ESP

And make sure the marketing sender has SPF + DKIM + DMARC alignment, rather than merely having DMARC published. Gmail specifically checks alignment for bulk direct mail. support.google.com

Bottom line: I'd choose Google Workspace + a dedicated marketing/transactional ESP. If you tell me roughly how many marketing emails you send per month and whether they're cold outreach, newsletters, or product/transactional emails, I can recommend the best specific stack (e.g. HubSpot vs Customer.io vs Klaviyo vs SendGrid/Postmark/SES) and the domain/DNS setup.

For a SaaS marketer, I’d pick Google Workspace as the default, especially if your team primarily emails prospects, customers, partners, and other SaaS/tech companies.

My shortlist

Why Google Workspace: Gmail has very strong receiving-side infrastructure, and Google explicitly recommends SPF, DKIM, and DMARC for better delivery. For bulk senders to Gmail, SPF + DKIM + DMARC are required. support.google.com

Google Workspace

Microsoft 365 is equally credible if your organization lives in Outlook/Teams. Microsoft supports DKIM for custom domains and recommends configuring SPF and DMARC alongside it. It also specifically recommends using separate subdomains for third-party/bulk email systems so their reputation doesn't affect your primary domain. learn.microsoft.com

Microsoft 365

Fastmail is a nice choice if you want a simpler mail platform without the broader Google/Microsoft productivity suites. It supports custom domains and DKIM, and its setup wizard can help configure SPF/DKIM. www.fastmail.help

Fastmail

One important SaaS-marketing distinction

If by "SaaS marketer" you mean marketing campaigns/newsletters, I would not use your normal email-hosting platform as the bulk-email sender.

I'd structure it roughly like:

• you@company.com → Google Workspace
• marketing.company.com → your marketing/email platform
• company.com → corporate/transactional identity
• Configure SPF + DKIM + DMARC for every relevant sending domain/subdomain.
• Ideally keep marketing/transactional sending on subdomains so reputation problems don't contaminate employee mail.

That's particularly important because authentication is now a core Gmail deliverability requirement. support.google.com

Bottom line: Google Workspace + a dedicated marketing sender is my recommendation for most SaaS companies. If you're choosing specifically for outbound sales rather than newsletters, I can also compare the best setup for cold outbound vs. lifecycle email vs. newsletters.

For a SaaS marketer, I’d pick Google Workspace as the default, with Microsoft 365 as the strongest alternative.

My recommendation: Google Workspace

If you're sending normal 1:1 sales/marketing email from addresses like you@yourcompany.com, Workspace is hard to beat. Google explicitly recommends SPF, DKIM, and DMARC, and says authenticated messages are less likely to be rejected or marked as spam. support.google.com

The important distinction is that email hosting and marketing-email sending are separate concerns. I'd structure it like:

• Google Workspace → employee inboxes (name@company.com)
• Marketing/transactional ESP → newsletters, product emails, automated campaigns
• Dedicated subdomain for bulk/marketing sending, e.g. news.company.com or mail.company.com
• SPF + DKIM + DMARC configured for every sending domain/subdomain
• Gradually move DMARC from p=none → quarantine → reject once you've verified all legitimate senders.

This separation is particularly useful for protecting the reputation of your main corporate domain. Microsoft similarly recommends using a subdomain for bulk-mail services so problems with that service don't affect the reputation of the primary domain. learn.microsoft.com

When I'd choose Fastmail instead

If you don't need the Google ecosystem and mainly want excellent hosted email without the collaboration-suite overhead, Fastmail is compelling. It supports custom domains and provides SPF/DKIM/DMARC configuration; its domain setup wizard can automatically configure DKIM/SPF when Fastmail hosts your DNS. www.fastmail.help

Fastmail Business

Bottom line: Google Workspace + a dedicated marketing ESP/subdomain would be my choice for a SaaS marketer who cares seriously about deliverability. The hosting platform itself isn't what makes marketing email land in the inbox; authentication, domain reputation, sending practices, engagement, and the reputation of your bulk-sending infrastructure matter enormously. support.google.com

If you tell me whether you're doing mostly cold outbound, newsletters/lifecycle email, or transactional email, I can recommend the specific stack (e.g. Workspace + HubSpot/Customer.io/SendGrid/etc.) and DNS setup.

For a SaaS marketer, I’d pick Google Workspace as the default, with Microsoft 365 as the strongest alternative.

My recommendation: Google Workspace

For a SaaS marketing team, Google Workspace gives you the best overall combination of mailbox reputation, Gmail compatibility, administration, and authentication support. I'd use it for your actual employee/team inboxes.

The important distinction, though: don't treat your mailbox provider as your marketing-sending infrastructure. If you're sending newsletters, product announcements, or high-volume outbound campaigns, use a dedicated ESP and authenticate that sending domain separately.

A clean setup would look like:

• yourcompany.com → Google Workspace for employee mail
• mail.yourcompany.com or marketing.yourcompany.com → marketing/transactional sending
• SPF → authorize the appropriate senders
• DKIM → enable signing for every sending platform
• DMARC → start with monitoring (p=none), then move toward quarantine/reject once legitimate senders are confirmed

Microsoft explicitly recommends using subdomains for email systems you don't directly control so that problems with a marketing service don't damage the reputation of your primary domain. learn.microsoft.com

When I'd choose Microsoft 365 instead

If your SaaS sells primarily to larger enterprises, particularly organizations heavily invested in Outlook/Exchange, I'd seriously consider Microsoft 365. It supports custom-domain DKIM and DMARC, and Microsoft provides explicit tooling for configuring both. learn.microsoft.com

Bottom line:
Google Workspace + a dedicated marketing ESP + properly configured SPF/DKIM/DMARC is the setup I'd recommend for most SaaS marketers. The email host alone won't guarantee inbox placement; domain reputation, authentication, sending behavior, complaints, and list quality matter enormously.

If you tell me your approximate monthly email volume and whether you're doing newsletters, lifecycle email, or cold outbound, I can recommend the specific stack (e.g. Workspace + HubSpot/Customer.io/SendGrid/etc.) and the domain/DKIM/DMARC architecture I'd use.

For a SaaS marketing team, I’d pick Google Workspace for employee/business email, and keep your high-volume marketing/transactional sending on a dedicated ESP such as Customer.io, SendGrid, or Amazon SES rather than sending campaigns directly through your mailbox provider.

My recommendation

1. Google Workspace — best overall

• Excellent reputation and generally strong inbox placement.
• Custom-domain email (you@yourcompany.com).
• Full SPF + DKIM + DMARC support.
• DKIM is straightforward to configure through the Admin console. knowledge.workspace.google.com
• Particularly attractive if your team already lives in Gmail/Docs/Calendar.
• Google's current guidance recommends setting up SPF, DKIM, and DMARC for your domain; bulk senders to Gmail are required to have all three. support.google.comlearn.microsoft.com

Google Workspace

2. Microsoft 365 — best if you're an Outlook/Teams shop

• Also excellent for custom-domain business email.
• Supports DKIM and DMARC, including custom domains and subdomains. learn.microsoft.com
• I'd choose it over Google Workspace if your company is already heavily invested in Microsoft 365.

Microsoft 365

3. Zoho Mail — good budget option

• Worth considering if minimizing per-seat cost matters more than having the strongest overall ecosystem.
• Supports custom domains and standard authentication, but I'd still favor Google Workspace for a SaaS company where email reputation and operational simplicity are important.

One important SaaS-marketer distinction

Don't confuse email hosting with marketing email infrastructure.

I'd structure your DNS roughly like:

yourcompany.com
    └── Google Workspace
        ├── employee email
        └── SPF + DKIM + DMARC

mail.yourcompany.com / marketing.yourcompany.com
    └── dedicated marketing ESP
        ├── DKIM
        ├── SPF
        └── separate sending reputation

Using a subdomain for bulk/marketing sending is specifically recommended by Microsoft because problems with a third-party bulk sender then don't directly damage the reputation of your primary employee-mail domain. learn.microsoft.com

Also, Gmail currently requires bulk senders (>5,000 Gmail messages/day) to use SPF, DKIM, and DMARC, with DMARC alignment and one-click unsubscribe requirements for marketing/subscribed messages. support.google.comlearn.microsoft.com

Bottom line: Google Workspace + a dedicated marketing ESP is the setup I'd choose for most SaaS companies. If you tell me your approximate monthly marketing-email volume and team size, I can recommend the best ESP to pair with it too.

For a SaaS marketing team, I’d recommend Google Workspace as the default choice.

My pick: Google Workspace

Google Workspace gives you Gmail on your own domain, mature spam/inbox infrastructure, and straightforward support for SPF, DKIM, and DMARC. Google specifically recommends authenticating your domain with SPF/DKIM and, for bulk senders, DMARC as well. support.google.com

Google Workspace business email

Why I'd choose it for SaaS:

• Excellent reputation/deliverability for normal business email.
• Custom-domain Gmail (you@yourcompany.com).
• Full DKIM + SPF + DMARC support.
• Good admin tooling as your team grows.
• Excellent integration with Google Calendar, Drive, Meet, etc.
• Particularly convenient if your marketers live in Gmail.

One important distinction: don't use your regular Workspace mailbox infrastructure as your marketing-sending platform. If you're sending newsletters, product announcements, lifecycle email, etc., I'd use a dedicated email-sending provider and ideally a subdomain such as mail.yourcompany.com or marketing.yourcompany.com. Microsoft explicitly recommends subdomains for bulk-email services so their reputation doesn't affect the primary domain. learn.microsoft.com

If you want alternatives

Microsoft 365 — probably my second choice. Very strong if your company already lives in Outlook/Teams/Excel. It supports custom-domain DKIM and DMARC, although the DNS/authentication setup is somewhat more involved. learn.microsoft.com

Fastmail — attractive if you want email hosting specifically rather than a full productivity suite. It's standards-oriented and relatively lightweight, but I'd still favor Workspace for a typical SaaS marketing organization.

Proton Mail Business — compelling if privacy is a major requirement, but privacy isn't usually the deciding factor for a SaaS marketing team.

The setup I'd actually use

I'd separate employee email from marketing/transactional sending:

That separation matters more to deliverability than simply picking one "good email host." Gmail's current requirements explicitly emphasize authentication, DMARC alignment, spam rates, and appropriate sending practices. support.google.com

Bottom line: If you want one answer, Google Workspace + a dedicated marketing/transactional ESP is the setup I'd recommend for a SaaS company.

For a SaaS marketing team, I’d pick Google Workspace for your human/team email, and use a dedicated transactional/marketing sender separately if you’re sending product emails or campaigns at scale.

My ranking

1. Google Workspace — my recommendation.
Gmail has strong receiving-side reputation, and Google explicitly recommends SPF, DKIM and DMARC for domain authentication. For bulk senders, Google requires all three and also looks at spam rates and DMARC alignment. support.google.com

Google Workspace

2. Microsoft 365 is equally credible if your company lives in Outlook/Teams/Office. I'd choose it over Google primarily for ecosystem reasons rather than deliverability.

Microsoft 365

3. Fastmail is a particularly nice option if you want email hosting rather than a productivity suite. It supports custom domains and DKIM, and provides explicit SPF/DKIM/DMARC configuration. www.fastmail.help

Fastmail

One important SaaS-marketing distinction

I wouldn't use your primary Google Workspace/Microsoft 365 domain as the engine for marketing campaigns.

I'd structure it roughly like:

• yourcompany.com → employee email / normal correspondence
• mail.yourcompany.com or a dedicated sending subdomain → marketing/transactional sending
• SPF + DKIM + DMARC on each relevant sending domain/subdomain
• Gradually increase sending volume rather than suddenly blasting a new domain
• Monitor DMARC reports and Gmail/Yahoo spam metrics

That separation protects the reputation of your employees' normal mail if a campaign has poor engagement.

Bottom line: If you want the safest default, Google Workspace + a dedicated email sending platform for marketing/transactional mail is what I'd deploy for a SaaS company. Google Workspace itself is excellent for your team's inboxes, but it's not a substitute for an ESP when you're sending substantial marketing volume.

For a SaaS marketer, I’d pick Google Workspace for your primary business email, and keep your marketing/bulk sending on a dedicated platform such as Customer.io, HubSpot, SendGrid, or Amazon SES.

My recommendation: Google Workspace

Google Workspace is the best default if you want reliable day-to-day email plus straightforward domain authentication.

Why:

• Strong deliverability: Gmail has excellent infrastructure and reputation, provided your sending practices are clean.
• DKIM: You can authenticate your custom domain with DKIM.
• DMARC: You can publish and manage a DMARC policy for your domain.
• SPF: Supported as part of the authentication setup.
• Excellent ecosystem: Gmail, Calendar, Drive, Meet, etc. are useful for a SaaS marketing team.
• Good separation of roles: You can use you@company.com for personal/business correspondence while sending campaigns from something like hello@company.com through a dedicated ESP.

Google explicitly recommends SPF, DKIM, and DMARC, and says authenticated messages are less likely to be rejected or marked as spam. Bulk senders to Gmail are required to have all three. support.google.com

If cost is the priority: Zoho Mail

Zoho Mail is a very solid lower-cost alternative. It supports custom domains, DKIM selectors, SPF, and DMARC, including DMARC reporting in its admin console. support.google.comwww.zoho.com

Zoho Mail

One important distinction

Don't use your regular email host as your marketing-email infrastructure.

For example:

This separation protects your main domain's reputation. For a SaaS company doing meaningful outbound/newsletter volume, I'd particularly consider using a dedicated sending subdomain rather than sending campaigns directly from the same infrastructure as employee mail.

Bottom line: I'd choose Google Workspace + a dedicated marketing/transactional email provider. If you're a small team and budget-conscious, Zoho Mail is the alternative I'd investigate first.

If you tell me roughly how many marketing emails/month you send and whether they're newsletters, lifecycle emails, cold outbound, or all three, I can recommend the specific stack I'd use.