Proton Mail IMAP Settings

IMAP keeps your mail on Proton Mail's servers and mirrors it to every device you connect. Read a message on your phone and it shows as read on your laptop; file it into a folder and that folder appears everywhere. That synchronisation is the whole point of IMAP, and it is why it is the right choice for almost everyone connecting Proton Mail to a desktop or mobile mail client.

Proton Mail IMAP settings

Enter these values in your mail client's incoming server section:

Your username is normally your full email address, and the password is whatever your account requires — which, as the notes below explain, is not always the password you type into the website.

Before you start

• Requires: Proton Mail Bridge, available on paid plans only
• Why localhost: Bridge runs on your machine and decrypts locally, so clients connect to 127.0.0.1 rather than a Proton server
• Credentials: Bridge issues its own username and password — not your Proton login

Adding the account to a mail client

Nearly every mail client follows the same shape. Open your account settings, choose to add a new account, and pick the manual, advanced or "other" option rather than letting the application guess. Automatic detection is convenient when it works, but it regularly picks the wrong port or silently configures POP3 instead of IMAP — and a mail client that has quietly downloaded and deleted your server-side mail is a far worse problem than a few extra fields to fill in.

Enter the incoming server exactly as listed above, choose the matching encryption, then enter your outgoing details from the SMTP guide. If the client offers to test the connection before saving, let it: a failure at this point is trivial to diagnose, whereas an account that appears to work but stops syncing a week later is genuinely painful to unpick.

Folders and syncing

Once connected, your client will download the folder list from the server. Some clients map special folders — Sent, Drafts, Trash, Spam — automatically; others need to be told which server folder corresponds to each. Getting this wrong produces the classic symptom of sent messages appearing twice, or drafts that vanish when you switch devices. It is worth checking that mapping once, at setup, rather than wondering about it later.

Most clients also let you choose how much mail to keep locally. Synchronising everything gives you offline access and fast search at the cost of disk space; synchronising only recent messages keeps things light on a laptop with a small drive. Neither choice changes what is stored on the server.

If it will not connect

Three causes account for the overwhelming majority of failures. The first is the wrong kind of password: several providers require a generated app password for mail clients, and your normal sign-in password will simply be refused no matter how carefully you type it. The second is IMAP access being switched off in the web interface, which some providers disable by default and which no amount of correct configuration in your client can work around.

The third is a mismatch between port and encryption. Ports and encryption methods travel in pairs: port 993 expects SSL/TLS. Pairing it with STARTTLS fails even though both values are individually correct, and the resulting error usually mentions the connection rather than the settings, which sends people hunting in the wrong place.