Creating an app password for Fastmail

Two minutes at app.fastmail.com, and you only do it once.

Nevermore signs in to Fastmail over IMAP with an app password: a separate, revocable password that works for one app and nothing else. Your ordinary account password will not work, and that is deliberate — there is no OAuth consent screen and no third party in the middle. Fastmail requires an app password for IMAP: your ordinary login password will not work, whether or not you use two-factor authentication.

Creating one

In the Fastmail web app, open Settings, then Privacy & Security.
Under Connected apps & API tokens, choose Manage app passwords and access. You can go straight there at app.fastmail.com.
Choose New app password and name it. Fastmail may ask for your account password first.
Leave the access set to Mail, Contacts & Calendars — that is the one that includes IMAP, which is all Nevermore uses.
Choose Generate password and copy the result.

Fastmail's Basic plans do not include IMAP, and cannot create app passwords at all. If the option is missing, check which plan the account is on.

Fastmail's own instructions →

Then, in Nevermore

Paste it into the App password field on Nevermore's sign-in screen. Spaces are fine — the app strips them. It goes straight into the macOS Keychain, is never written to disk in the clear, and never leaves your Mac.

An app password is a credential: it grants access to your mailbox. Put it in Nevermore's password field, and nowhere else — not into a note, an email to yourself, or a chat window. If you ever want to cut Nevermore off, delete the app password at your provider; nothing else about your account changes.

If sign-in still fails

Check you entered the app password, not your normal account password. Providers reject both with the same error, so the message looks identical.
Most providers show the password only once and cannot show it again. If you did not copy it, delete that one and create another — they are free and disposable.
If you deleted the password at your provider, or changed something about the account, create a new one and re-enter it.
Still stuck? Get in touch — include your provider and what the error said.

Checked against Fastmail's own instructions on 22 August 2026. Providers move these settings without warning; if what you see does not match, their page is the authoritative one and we would be glad to hear about it.