Comparison · facts checked 2026-09

SuperMailOS vs Fastmail

Every domain in one inbox, with DMARC you can read.Fastmail is one of the best independent email hosts there is — polished apps, calendars and contacts, billed per user. SuperMailOS trades the extras for multi-domain focus: every domain converges into one inbox, aliases are free everywhere, and your DMARC reports land in a dashboard.

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The short answer

Choose Fastmail ifYou want a polished personal or team mailbox with calendars and contacts.

Choose SuperMailOS ifYou need many domains in one inbox, with DMARC visibility and free aliases everywhere.

Fastmail details from public sources, 2026-09. Where they win comes first.

01 Side by side

Fastmail and SuperMailOS, row by row.

An honest, current comparison. Where we're unsure of a competitor detail, we describe what SuperMailOS does rather than assert theirs.

Feature and price comparison: Fastmail versus SuperMailOS.
Feature	Fastmail	SuperMailOS
Product model	FastmailIndependent hosted email with calendars and contacts; billed per user, tiered	SuperMailOSHosted email, per mailbox — every domain converges into one inbox
Entry price	FastmailFrom about $3/user/mo; custom-domain hosting starts on the Standard tier (~$5–6/user/mo), as of 2026-09	SuperMailOSPro $4/mo per mailbox ($3 annual) · Business $6/mo ($5 annual)
Custom domains	FastmailPartlySupported on higher tiers	SuperMailOSYesEvery plan; Business is unlimited domains
Aliases	FastmailYesGenerous aliases and masked email	SuperMailOSYesUnlimited and free, on every domain
IMAP & SMTP	FastmailYesFull IMAP/SMTP	SuperMailOSYesEvery plan (993/465, SSL)
Two-factor auth	FastmailYesSupported	SuperMailOSYesTOTP 2FA + session management
Managed deliverability	FastmailExcellent infrastructure; you add the DNS records they provide	SuperMailOSManaged, plus DMARC reports parsed to a dashboard and automatic warm-up
DMARC report dashboard	FastmailPartlyConfigure DMARC in DNS; no aggregate-report dashboard	SuperMailOSYesAggregate reports parsed into a dashboard
Calendars & contacts	FastmailYesBuilt in	SuperMailOSNoEmail-focused

Included With caveats Not includedFastmail details compiled from public sources as of 2026-09 and may have changed since. SuperMailOS details reflect current plans.

02 Honestly

Where Fastmail is the better choice.

If any of these describe you, Fastmail is probably the right call — and that's fine.

A mature, independent product

Years of polish, excellent native apps, a clear privacy stance and a reputation earned over a long time.

More than mail

Calendars, contacts and masked email are built in — a genuinely broader personal-productivity story than email alone.

Great deliverability reputation

Long-running, well-managed sending infrastructure with a strong inbox-placement track record.

And where SuperMailOS is

Multi-domain economics

Every domain converges into one inbox with aliases free, and Business is unlimited domains on one bill — not a per-user tier you climb as addresses multiply.

DMARC you can actually read

Aggregate DMARC reports are parsed into a dashboard instead of arriving as XML attachments, and new domains warm up automatically.

One-click DNS with live verification

Publish records on Cloudflare, DigitalOcean, Linode, Vultr, Hetzner DNS or Spaceship in a click, and watch them verify before you send.

Priced per mailbox, features included

Deliverability, unlimited aliases and IMAP/SMTP are included rather than gated behind a higher tier.

Which one fits you

Fastmail is an easy recommendation if you want a polished personal or team mailbox with calendars and contacts. If your need is many domains in one inbox, with DMARC visibility and free aliases everywhere, SuperMailOS is built for exactly that — and IMAP/SMTP and 2FA are a tie, so you give up neither.

SuperMailOS is hosted business email: we run the mail server, the sending IPs and the deliverability work, so there's nothing to self-host and no server to keep alive.

03 Price

What it costs
at your team size.

Per mailbox against per user, both billed yearly. Aliases never count on our side, so hello@ and support@ add nothing.

SuperMailOS Pro · up to 3 domains: $3/mo
SuperMailOS Business · unlimited domains: $5/mo
Fastmail: $5/user/mo

What you'd pay Yearly

People4

Domains2

SuperMailOS Pro$12/mo

Fastmail$20/mo

You'd keep

$96a year

Pro covers up to 3 domains. Aliases are free on both.

Fastmail's Standard tier — where custom-domain hosting starts — is about $5–6 per user a month as of 2026-09; this uses the low end.

Still comparing? Ask your AI — we've written the question.

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04 Switching

Switch in an afternoon. Keep your domain.

Your domain stays where you bought it. Nothing to install, and your old mail can come with you.

Point your domain

One click on Cloudflare, DigitalOcean, Linode, Vultr, Hetzner DNS and Spaceship. Anywhere else, we show you exactly what to paste.

Create your addresses

A mailbox for each person, and free aliases for everything else — hello@, billing@, support@.

Keep your apps

Use the web app, or Apple Mail, Outlook and Thunderbird over IMAP. An iPhone app is coming soon.

05 Questions

Questions people ask.

Something else? Write to us — a real person answers, usually the same day.

Talk to us

Does Fastmail support IMAP and SMTP?+

Yes — both Fastmail and SuperMailOS provide full IMAP and SMTP with app passwords (SuperMailOS on 993/465, SSL). On this one, it's a tie.

Does Fastmail handle deliverability?+

Fastmail runs excellent sending infrastructure and gives you the DNS records to add for your domain. SuperMailOS also manages authentication, and additionally parses your aggregate DMARC reports into a dashboard and warms up new domains automatically (as of 2026-09).

What about multiple domains?+

Fastmail supports custom domains on its higher tiers, billed per user. SuperMailOS puts every domain into one inbox, and Business covers unlimited domains on one bill, with free aliases on all of them.

I already host domains on Fastmail — how hard is the move?+

Point the domain's MX at the managed server using the DNS records we generate, verify them live, then migrate mailboxes over IMAP. It's typically under five minutes per domain before the data move.

How does pricing compare?+

Fastmail bills per user, tiered by features (from about $3/user/mo as of 2026-09). SuperMailOS is per mailbox — Pro $4/mo, Business $6/mo — with aliases, IMAP/SMTP and deliverability included rather than tiered.

Bring every domain home.

Try it free for 14 days. No card, and your domain stays yours.

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