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.
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.
This is the detailed head-to-head. Prefer the shorter overview? Read the Fastmail alternative guide
Fastmail and SuperMailOS, side by side
An honest, current comparison. Where we’re unsure of a competitor detail we describe what SuperMailOS does rather than assert theirs.
| Feature | Fastmail | SuperMailOS |
|---|---|---|
| Product model | Independent hosted email with calendars and contacts; billed per user, tiered | Hosted email, per mailbox — every domain converges into one inbox |
| Entry price | From about $3/user/mo; custom-domain hosting starts on the Standard tier (~$5–6/user/mo), as of 2026-09 | Pro $4/mo per mailbox ($3 annual) · Business $6/mo ($5 annual) |
| Custom domains | Supported on higher tiers | Every plan; Business is unlimited domains |
| Aliases | Generous aliases and masked email | Unlimited and free, on every domain |
| IMAP & SMTP | Full IMAP/SMTP | Every plan (993/465, SSL) |
| Two-factor auth | Supported | TOTP 2FA + session management |
| Managed deliverability | Excellent infrastructure; you add the DNS records they provide | Managed, plus DMARC reports parsed to a dashboard and automatic warm-up |
| DMARC report dashboard | Configure DMARC in DNS; no aggregate-report dashboard | Aggregate reports parsed into a dashboard |
| Calendars & contacts | Built in | Email-focused |
Fastmail details compiled from public sources as of 2026-09 and may have changed since. SuperMailOS details reflect current plans.
Where Fastmail wins
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.
Where SuperMailOS wins
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 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.
What you get with SuperMailOS, on every plan
We run the mail server, so the parts other tools leave to you are simply included:
Deliverability is operated, not DIY
DKIM signs every message; SPF and DMARC are published from the mail server's own zone and verified live before you can send. DMARC reports are parsed into a dashboard, sending-IP reputation and reverse DNS are watched, and new domains warm up automatically.
IMAP & SMTP on every plan
Standard IMAP (993, SSL) and SMTP (465, SSL) with per-mailbox app passwords, so Apple Mail, Outlook, Thunderbird or any client just works — the webmail is optional, not the only door.
A real threaded inbox
Conversations, instant search, labels, drafts, signatures and keyboard shortcuts — across every domain you connect, in one place. Reply as any address on any domain.
Cc and Bcc done properly
Full Cc and Bcc with privacy preserved: a Bcc line is only ever shown to the sender or a recipient who was themselves Bcc'd, and Bcc never affects threading.
Two-factor & session control
TOTP two-factor authentication and session management on your account, so a leaked password alone can't open your mail.
One-click DNS
Publish the records with one click on Cloudflare, DigitalOcean, Linode, Vultr, Hetzner or Spaceship — or copy-paste anywhere else. Provider tokens are used once and never stored.
Dark mode, everywhere
A genuine dark theme across the whole app and marketing site, tuned for contrast — not an inverted screenshot.
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.
Questions people ask
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.
Related
Bring your domain. We'll carry the rest.
The first domain is live in minutes, every domain after that is a click, and aliases are free on all of them.
14 days free · no credit card · your own domain