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Fastmail IMAP and SMTP settings

By Julien CoulaudPublished November 1, 20264 min read

These are the settings Fastmail publishes for mail, calendar and contacts apps, checked on Fastmail's help pages on November 1, 2026. Two things trip people up: Fastmail only accepts an app password in third-party apps, and Basic plans include no IMAP or SMTP at all.

Julien Coulaud on X

Founder of Shipmail, the email platform for businesses and their AI agents. Every guide here draws on mail servers running in production.

  • Fastmail
  • IMAP
  • SMTP
  • App passwords

Short answer

The Fastmail IMAP server is imap.fastmail.com on port 993 with SSL/TLS, and the SMTP server is smtp.fastmail.com on port 465 with SSL/TLS, or 587 with STARTTLS for apps that only offer STARTTLS. Sign in with your full Fastmail username and an app password, because Fastmail says your regular password will not work in other apps.

Fastmail mail server settings

ProtocolServerPortEncryption
IMAP, incoming[1]imap.fastmail.com993SSL/TLS on, STARTTLS off
SMTP, outgoing[1]smtp.fastmail.com465, or 587 for STARTTLS-only appsSSL/TLS on 465, STARTTLS on 587, authentication required
POP, incoming[1]pop.fastmail.com995SSL/TLS on, STARTTLS off

Fastmail IMAP settings

  • Incoming mail server: imap.fastmail.com
  • Port: 993
  • SSL/TLS: on. STARTTLS: off
  • Username: your full Fastmail username, including the domain, for example name@fastmail.com
  • Password: an app password
  • Root folder or path prefix: leave it blank. The folder separator is /
  • Secure password authentication (SPA): leave it off
[1]

Use the username you signed up with. Fastmail says other addresses on the account will not work as the login, even if you send from them. If your app chokes on the @ in the username, Fastmail accepts username#your.domain, username/your.domain or username=your.domain instead.[1]

Fastmail SMTP settings

  • Outgoing mail server: smtp.fastmail.com
  • Port: 465 with SSL/TLS on and STARTTLS off
  • If your app only supports STARTTLS: port 587 with STARTTLS
  • Authentication: PLAIN, with the same username and app password as incoming mail
[1]

Port 465 is Fastmail's first choice. The difference between 465 and 587 is only when encryption starts, which our guide to SMTP ports explains.[1]

Fastmail POP settings

POP uses pop.fastmail.com on port 995 with SSL/TLS on and STARTTLS off. It downloads the Inbox only. To download another folder, add it to the username after a plus sign, as in name+Archive@fastmail.com. Folder names are case sensitive, and folders with special characters do not work this way.[1]

How to create a Fastmail app password

Fastmail requires an app password for every third-party mail, calendar and contacts app. Each app gets its own, so you can revoke a lost laptop without changing your main password, and an app password cannot be used to change your account settings.Sources[2]Fastmail app passwords[1]Fastmail: server names and ports

  1. Step 1

    Open the settings

    Sign in to Fastmail on the web and go to Settings, then Privacy & Security.

  2. Step 2

    Manage app passwords

    Under Connected apps & API tokens, click Manage app passwords and access, then New app password. Enter your password if Fastmail asks you to verify it's you.

  3. Step 3

    Name it and choose the access

    Pick a suggested name or enter your own. The default access, Mail, Contacts & Calendars, covers IMAP, POP, SMTP, CardDAV and CalDAV.

  4. Step 4

    Generate and paste it

    Click Generate password, paste it into your app, and check that the account works before you click Done.

[2]

Fastmail calendar and contacts servers

  • Calendars (CalDAV): https://caldav.fastmail.com/, SSL/TLS required. Apps without auto-discovery need the full calendar URL from Settings, Calendars, Export.
  • Contacts (CardDAV): https://carddav.fastmail.com/, SSL/TLS required.
  • Both use the same username and an app password with calendar or contacts access.
Sources[1]Fastmail: server names and ports[2]Fastmail app passwords

Fastmail sending limits

Fastmail limits sending per user per day, and one message to five people counts as five. The hourly limit is half the daily one, and the 10-minute limit is half the hourly one.[3]

  • Basic and Business Basic: 4,000 messages and 1 GB a day
  • Standard, Individual and Business Standard: 8,000 messages and 2 GB a day
  • Duo and Family: 8,000 messages and 2 GB a day for each user
  • Professional and Business Professional: 16,000 messages and 4 GB a day
  • Trial accounts: 120 messages a day until the account is paid
  • Message size: 70 MB including encoding, so attachments top out around 50 MB
[3]

Common Fastmail connection problems

  • The app rejects your password: you entered your Fastmail password. Create an app password and use it instead.
  • You cannot find app passwords: you are on the Basic plan, which has no IMAP or SMTP.
  • Login fails with the right password: you used an alias as the username. Use the username you signed up with.
  • A network blocks the normal ports: Fastmail runs imaps-proxy.fastmail.com, pops-proxy.fastmail.com and smtps-proxy.fastmail.com, which accept any port with SSL/TLS, such as 443.
  • Folders look wrong: clear the IMAP path prefix in your app's advanced settings.
Sources[1]Fastmail: server names and ports[2]Fastmail app passwords

The same app password lets another service copy your Fastmail mail over IMAP. Shipmail's connected import lists Fastmail among its sources and can be run again after a switch to pick up late mail. For plans and features, see the Shipmail and Fastmail comparison instead; this page only covers connecting the account you have.Sources[5]Shipmail mailbox import documentation[2]Fastmail app passwords

Using a mailbox on your own domain instead

An address such as name@fastmail.com belongs to Fastmail, so leaving Fastmail means giving everyone a new address. An address on a domain you own keeps working wherever you host the mailbox.

A Shipmail mailbox on your own domain works in the same apps with one set of settings: server mx1.shipmail.to, IMAP on port 993 with SSL/TLS, SMTP on port 465 with SSL/TLS or 587 with STARTTLS, and your full address as the username. Plans start at $4 a month for 2 mailboxes. It is not free, and it only makes sense if you want an address you own rather than one tied to a provider.Sources[4]Shipmail email client connection settings[6]Shipmail pricing

Sources6 sourcesVerified 2026-11-01
  1. [1]
    Fastmail: server names and ports

    IMAP imap.fastmail.com port 993 and POP pop.fastmail.com port 995, both SSL/TLS on and STARTTLS off. SMTP smtp.fastmail.com port 465 with SSL/TLS and PLAIN authentication, or port 587 with STARTTLS for clients that only support STARTTLS. Leave the IMAP path prefix blank and do not enable SPA. POP reads the Inbox unless a folder is appended to the username with +. CalDAV https://caldav.fastmail.com/ and CardDAV https://carddav.fastmail.com/. Every service needs an app password and the full sign-up username; the regular password will not work. Firewall proxies imaps-proxy, pops-proxy and smtps-proxy.fastmail.com accept any port with SSL/TLS. Basic plans include no IMAP, SMTP, CalDAV or CardDAV.

    fastmail.help · 2026-11-01

  2. [2]
    Fastmail app passwords

    Create an app password in Settings, Privacy & Security, Connected apps & API tokens, Manage app passwords and access. The default Mail, Contacts & Calendars scope covers IMAP, POP, SMTP, CalDAV and CardDAV. Basic plans include no IMAP, SMTP, CalDAV or CardDAV, so they cannot create app passwords.

    fastmail.help · 2026-11-01

  3. [3]
    Fastmail: account limits

    Daily sending limits per user: Basic 4,000 messages and 1 GB, Standard or Individual 8,000 and 2 GB (Duo and Family 8,000 and 2 GB per user), Professional 16,000 and 4 GB, with the Business plans matching. A message to several recipients counts once per recipient. Hourly limits are half the daily limit and 10-minute limits half the hourly one, with smaller caps on distinct recipients. Trial accounts may send 120 messages a day. Messages may be at most 70 MB including encoding, so attachments are usually limited to about 50 MB.

    fastmail.help · 2026-11-01

  4. [4]
    Shipmail email client connection settings

    Shipmail IMAP, SMTP, and JMAP settings: mx1.shipmail.to, IMAP on port 993 with SSL/TLS, SMTP on port 465 with SSL/TLS or 587 with STARTTLS, the full email address as username, and the mailbox password or an app password.

    shipmail.to · 2026-10-15

  5. [5]
    Shipmail mailbox import documentation

    Shipmail documentation for connected and file imports, selection options, storage checks, progress, skipped items, and repeat imports.

    shipmail.to · 2026-10-15

  6. [6]
    Shipmail pricing

    Shipmail plan prices, mailbox limits, team access, and send limits.

    shipmail.to · 2026-10-15

Questions worth answering

Common questions about fastmail imap settings.

What are the Fastmail IMAP settings?
Server imap.fastmail.com, port 993, SSL/TLS on and STARTTLS off. Use your full Fastmail username and an app password, and leave the path prefix blank.[1]
What is the Fastmail SMTP server?
smtp.fastmail.com on port 465 with SSL/TLS, or port 587 with STARTTLS if your app only supports STARTTLS. Authentication is required.[1]
Why does my Fastmail password not work in Outlook or Apple Mail?
Fastmail only accepts an app password in third-party apps. Create one in Settings, Privacy & Security, Manage app passwords and access.Sources[2]Fastmail app passwords[1]Fastmail: server names and ports
Can I use IMAP on the Fastmail Basic plan?
No. Fastmail's Basic plan includes no IMAP, SMTP, CalDAV or CardDAV, so it cannot create app passwords. Use the web app or the Fastmail app, or move to a higher plan.[2]
How many emails can I send a day with Fastmail?
4,000 a day on Basic, 8,000 on Standard, Individual, Duo and Family, and 16,000 on Professional, counted per recipient. Trial accounts can send 120 a day.[3]

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