Two-factor authentication

Two-factor authentication (2FA) adds a second check beyond your password when you sign in — even if someone else learns your password, they still can't get into your account without your authenticator app.

It's opt-in: nothing changes about how you sign in until you turn it on yourself.

Turning it on

Go to Settings → Security and follow the Enable two-factor authentication prompt. You'll scan a QR code with an authenticator app — Google Authenticator, Authy, 1Password, and similar apps all work — then enter the 6-digit code it generates to confirm the pairing.

Two-factor authentication works the same way whether you normally sign in with Google or with a password — it's a second step added on top of either.

Authenticator apps only

MailInApp supports time-based one-time codes (TOTP) from an authenticator app. There's no SMS/text-message option, so make sure your authenticator app is set up and working before you turn this on — you'll need it every time you sign in from a new device or session.

Backup codes

Once two-factor authentication is on, generate a set of backup codes from Settings → Security. Each one is single-use — good for exactly one sign-in. Keep them somewhere safe (a password manager, printed and stored securely) for the day you don't have your authenticator app on hand: at a sign-in prompt, choose Use a backup code instead and enter one.

Using a backup code doesn't turn two-factor authentication off. Your account stays protected the same as before, and your remaining backup codes are still good for future use.

Lost your authenticator?

If you no longer have access to your authenticator app at all — a lost or reset phone, for example — choose Lost access to your authenticator? at the sign-in prompt. We'll email a one-time sign-in code to your account's email address.

Using that emailed code signs you in, but it also removes two-factor authentication from your account. Once you're back in, set it up again from Settings → Security if you'd like your account protected the same way going forward.