Setting up K-9 Mail

The instructions and screenshots in this setup guide are for the K-9 Mail app, which is an open source email client for Android.

You can easily add your Fastmail account to K-9 Mail using the setup guide in the Settings → Import & Setup screen. The general setup instructions are below.

K-9 Mail needs its own app password to access your information. If you use your normal password or your Fastmail two step verification password in K-9 Mail, syncing won't work and you will see a password error.

  1. Open the K-9 Mail app. If you don't already have an account set up, the Welcome to K-9 Mail screen appears. Tap on Next to go to the next page. Otherwise tap the + symbol on the navigation bar at the bottom of the screen.

    K-9 Mail Home screen

  2. On the Set up a new account screen, fill in your email address and app password.

    • Email address: Your full Fastmail username, including the domain.
    • Password: Your K-9 Mail app password. (What is an app password?)

    Tap Manual setup.

    Screen with username and password entered.

  3. On the Account type screen, Tap on IMAP.

    Screen which allows you to choose between IMAP/POP/Exchange

  4. Set the server settings for incoming email.

    • IMAP Server: imap.fastmail.com
    • Security: SSL/TLS
    • Port: 993
    • Authentication: Normal Password.
    • Auto-detect IMAP namespace: (leave ticked)
    • IMAP path prefix: (leave blank)
    • The Username and Password fields should be filled in. The password is your app password. (What is an app password?)

    Tap Next.

    Screen with incoming server settings entered

  5. Set the server settings for outgoing email.

    • SMTP Server: smtp.fastmail.com
    • Security: SSL/TLS
    • Port: 465
    • Require sign-in: (leave ticked)
    • Authentication: Normal Password.
    • The Username and Password fields should be filled in. The password is your app password. (What is an app password?)

    Tap Next.

    Screen with outgoing server settings entered

  6. Choose your synchronization and notification settings. Tap Next.

    Screen to adjust the notification and sychronization settings

  7. Enter the account name, your name and tap Done.

    Screen to enter your account name and your name

The K-9 mail app will now fetch the list of your folders and start synchronizing your mail!