Fastmail is a full email hosting provider, not a forwarding service. Mailboxes, calendars, contacts, file storage, and a modern API for custom domain email, hosted on infrastructure in Philadelphia and St. Louis (the company is Australian, but the data centers are American; an EU data-region option in Amsterdam is available). It appears in this category because it absorbed Pobox (one of the oldest pure forwarding services, founded 1995) in 2015. WordPress operators evaluating custom domain email will encounter it alongside the forwarding-only services.
The distinction matters. ImprovMX and Forward Email forward mail to an inbox you already have. Fastmail is the inbox. For forwarding alone, Fastmail is overkill at €5/month for something ImprovMX does for free. For a real mailbox on a custom domain with IMAP, a calendar, and an API, Fastmail is the independent alternative to Google Workspace at a comparable price point, with stronger privacy tooling and over a quarter century of operational history. (For a category overview, see the email forwarding services roundup.)
Fastmail was founded in 1999 in Melbourne by Rob Mueller, Bruce Davey, and Jeremy Howard. Opera Software acquired the company in 2010; the staff bought it back in 2013. It has been employee-owned and profitable since, with no external funding. The company also operates Topicbox (mailing list service) and Pobox (legacy forwarding, now migrated to Fastmail infrastructure).
Where Fastmail fits in a WordPress stack
Inbound email hosting. If [email protected] needs to be a real inbox, not just a forwarding alias, Fastmail provides IMAP/POP3 access, a web interface, calendar (CalDAV), contacts (CardDAV), and file storage (WebDAV). This is the mailbox layer: where domain email lives, where replies are read, where team accounts get set up.
Outbound SMTP. Fastmail’s SMTP server (smtp.fastmail.com, ports 465/587) can send email from the domain, and a WordPress SMTP plugin could be configured to use it. Fastmail does not publish sending limits, which means undisclosed rate limits exist and will surface at the worst moment. WordPress sites generating A transactional email is the automated message a WordPress site sends in response to a single user action – a password reset, an order confirmation, a form receipt – addressed to the user who triggered it. Read full reference → should use a dedicated sending service (Postmark, SMTP2GO, Mailgun) designed for that purpose. Use Fastmail for the admin’s personal mail; use a relay for WordPress-generated messages.
Pricing
Fastmail has no free tier. Its pricing sits between Forward Email and Google Workspace: a more mature product than Forward Email and more privacy-focused than Google.
Prices are in EUR (or local currency equivalent), shown at annual billing rates:
Individual plans
| Plan | Price (annual billing) | Storage | Custom domains |
|---|---|---|---|
| Individual | €5/month | 50 GB mail + 10 GB files | Yes |
| Duo (2 users) | €8/month total | 60 GB per user | Yes |
| Family (up to 6) | €11/month total | 60 GB per user | Yes |
Business plans (per user)
| Plan | Price (annual billing) | Storage | Custom domains |
|---|---|---|---|
| Basic | €3/month | 5 GB mail + 1 GB files | No |
| Standard | €5/month | 50 GB mail + 10 GB files | Yes |
| Professional | €9/month | 100 GB mail + 50 GB files | Yes |
The cheapest path to custom domain email on Fastmail is Business Standard or Individual, both at €5/month. Business Basic at €3/month does not support custom domains.
For context: ImprovMX forwards email for free (one domain, 25 aliases) and charges $9/month for SMTP sending. Forward Email provides unlimited free forwarding and $3/month mailbox hosting. Google Workspace starts at $7/month per user.
DNS setup
Fastmail offers three domain integration modes: full DNS delegation (NS records), MX-only, and no-NS/no-MX (subdomain addressing). MX-only is the right choice for most WordPress operators who already have DNS hosted elsewhere (Cloudflare, their registrar).
Two MX records, three DKIM selectors, SPF, and DMARC:
| Record type | Host | Value | Priority |
|---|---|---|---|
| MX | @ |
in1-smtp.messagingengine.com |
10 |
| MX | @ |
in2-smtp.messagingengine.com |
20 |
| TXT (SPF) | @ |
add include:spf.messagingengine.com to existing SPF record |
– |
| CNAME | fm1._domainkey |
fm1.yourdomain.com.dkim.fmhosted.com |
– |
| CNAME | fm2._domainkey |
fm2.yourdomain.com.dkim.fmhosted.com |
– |
| CNAME | fm3._domainkey |
fm3.yourdomain.com.dkim.fmhosted.com |
– |
| TXT | _dmarc |
v=DMARC1; p=none; |
– |
The messagingengine.com domain is Fastmail’s long-standing infrastructure domain. Three DKIM selectors (fm1, fm2, fm3) via CNAME records is more than most forwarding services require; the extra selectors allow Fastmail to rotate signing keys without DNS changes on the customer’s end.
The p=none DMARC policy is appropriate during initial setup and monitoring. After confirming legitimate mail passes authentication, tighten to p=quarantine or p=reject.
If no SPF record exists yet, create: v=spf1 include:spf.messagingengine.com ?all (Fastmail’s documented default uses neutral ?all; ~all softfail is a stricter alternative). If one already exists (common when also using a transactional relay), add the include: mechanism before the terminator. SPF allows up to 10 DNS lookups per RFC 7208 section 4.6.4; Fastmail’s include consumes one.
Fastmail supports SRS (Sender Rewriting Scheme) on forwarded messages for SPF alignment after forwarding, though it requires manual activation in account settings and is not recommended unless forwarding problems occur.
Aliases, Masked Email, and forwarding
Each Fastmail account supports up to 600 aliases, plus 15 additional aliases per user on multi-user plans. Three types of alias are available:
Standard aliases. Additional email addresses on a custom domain or on Fastmail’s domains (fastmail.com, sent.com, and others). Each alias delivers to the account’s mailbox.
Catch-all / wildcard. For custom domain owners, any email sent to an unmatched address at the domain is delivered to the catch-all destination. Available on all plans that support custom domains.
Masked Email. Auto-generated unique addresses (e.g. [email protected] or on a custom domain) designed to protect the real address when signing up for services. Each masked address can be set to active, blocked (delivers to Trash), or deleted (bounces). Masked Email integrates with 1Password and Bitwarden through their browser extensions, generating a new masked address at signup time. This is the same privacy-aliasing model as SimpleLogin or AnonAddy, built into the email provider rather than bolted on as a separate service.
Forwarding to external addresses is supported through Fastmail’s rules system. Any alias or catch-all can forward to a non-Fastmail address.
API and integration
Fastmail is one of the few email providers with a modern API. It implements JMAP (JSON Meta Application Protocol), a standard the company helped develop as an alternative to IMAP for programmatic email access. The session endpoint is https://api.fastmail.com/jmap/session.
Supported protocols:
- JMAP for mail, contacts, and (soon) calendars
- IMAP (RFC 9051) on
imap.fastmail.com, port 993 - POP3 (RFC 1939) on
pop.fastmail.com, port 995 - SMTP (RFC 5321) on
smtp.fastmail.com, ports 465/587 - CalDAV (RFC 4791) for calendars
- CardDAV (RFC 6352) for contacts
- WebDAV (RFC 4918) for file storage
Authentication for third-party apps uses Less Secure App (LSA) access was Google's name for the third-party authentication path that used a plain account password against Gmail's SMTP, IMAP, and POP endpoints. Google shut it down for consumer accounts on 30 May 2022 and for Workspace accounts on 1 May 2025; OAuth, App Passwords, or a different sending provider replace it. Read full reference → (generated in Settings > Privacy & Security). OAuth 2.0 is available for distributed applications but requires manual registration with Fastmail’s developer team.
The Masked Email API is a JMAP extension that allows programmatic creation and management of masked addresses. This is the integration point that 1Password and Bitwarden use.
What Fastmail does not do
Free forwarding. Every use case requires a paid account. If all that is needed is [email protected] forwarding to Gmail, ImprovMX or Forward Email handle this at no cost.
Transactional email relay. Fastmail does not document sending limits, does not provide bounce webhooks, and does not offer the deliverability tooling (suppression lists, engagement tracking, dedicated IPs) that a transactional relay provides. WordPress sites should not route wp_mail through Fastmail’s SMTP.
Self-hosting. Fastmail is a proprietary hosted service. The JMAP specification is open, but Fastmail’s implementation is closed. Forward Email is the only service in this category with a published codebase.
The verdict
Fastmail is the independent alternative to Google Workspace for operators who want domain email without Google’s data practices. At €5/month it matches Workspace’s entry price while offering Masked Email privacy aliases, a JMAP API, and the assurance of an employee-owned company with no advertising model. The trade-off is ecosystem: no Google Drive, no Google Meet, no deep integration with the rest of Google’s productivity suite. For operators whose needs are mailbox, calendar, contacts, and domain forwarding, that trade-off is easy.
It is not the right answer for forwarding alone. Paying €5/month for what ImprovMX does for free only makes sense if the mailbox, the calendar, and the privacy aliasing are also needed. For WordPress transactional email, Fastmail is the wrong tool entirely; use it for the admin inbox, pair it with Postmark or SMTP2GO for outbound delivery.