Proton Mail IMAP Settings: Server, Port and Bridge

Yes, Proton Mail supports IMAP, but only through Proton Mail Bridge, a desktop app that runs on your own computer. There is no imap.proton.me to type into Thunderbird or Apple Mail. The host is 127.0.0.1, which means your own machine, and the password is one that Bridge generates for you.

Bridge needs a paid Proton plan that includes Proton Mail. A free Proton account cannot use IMAP. The values are in the first table below, and the longer explanation of why Proton works this way comes after the setup steps.

Proton Mail IMAP and SMTP settings#

These are the values to enter in any email client that accepts manual IMAP and SMTP setup. They are Bridge's defaults. If you changed a port in Bridge, or switched its connection mode, use what Bridge shows for your account instead. Bridge lists the exact values for each account on its mailbox details screen.

• Host: 127.0.0.1. Port: 1143 for IMAP, 1025 for SMTP.
• Security: STARTTLS by default. Bridge can switch to SSL in its settings, and then your client must match.
• Username: your full Proton address. Password: the one shown inside Bridge, not your Proton login.
• Protocol: Bridge exposes IMAP and SMTP only. There is no POP3, so Proton Mail is IMAP, not POP.

What is the Proton Mail IMAP server address?#

There is no remote Proton Mail IMAP server address. The incoming server is 127.0.0.1 on port 1143, the loopback address of the computer running Bridge. Bridge signs in to Proton, decrypts your mail on that machine, and hands it to your email client through that local port.

That also explains why your client's automatic server detection fails for Proton addresses. Choose manual setup and type the values from the table.

Proton Mail SMTP server and port#

There are two SMTP routes, and they are for different jobs.

For everyday sending from a desktop client, use Bridge's SMTP server: 127.0.0.1, port 1025, STARTTLS by default, with your Proton address and the Bridge-generated password.

For apps, scripts and devices that cannot run Bridge, Proton also offers an SMTP submission service. Per Proton's support page, the host is smtp.protonmail.ch, the port is 587 and the encryption is STARTTLS. You sign in with an SMTP token you generate in your Proton account, not your login or mailbox password. Proton states it is available on paid plans with custom domain addresses, and the username is the custom-domain address you paired with the token. A plain @proton.me address is not covered by that route. It is for sending only, not for reading mail.

What you need before you start#

The plan requirement blocks more setups than any configuration step, so check these four things first.

• A paid Proton plan that includes Proton Mail. Proton's Bridge page says Bridge is available only with one.
• A supported desktop computer. Proton's requirements page currently lists 64-bit Windows 10 (22H2) and Windows 11, macOS 15 and macOS 26, the latest Ubuntu LTS and the latest Fedora Workstation. Other versions may work but are not fully tested, and the list changes, so check Proton's page for your version.
• The Bridge installer from proton.me/mail/bridge, downloaded directly from Proton.
• An email client that accepts a custom IMAP host and port, such as Thunderbird, Apple Mail or Outlook.

How to connect your email client in three steps#

This is the short version. The full walkthrough, with client-by-client screens, is in the full Proton Mail Bridge setup guide.

1. 1

   Install Bridge and sign in

   Install Bridge, open it and sign in with your Proton account. Bridge then builds a local copy of your mailbox, which takes longer for big accounts. Open your account inside Bridge and copy the generated password it shows.

2. 2

   Add the account manually in your client

   In Thunderbird, Apple Mail or Outlook, add a new account and choose manual IMAP setup. Decline automatic detection. Enter 127.0.0.1, port 1143 and STARTTLS for incoming mail, then 127.0.0.1, port 1025 and STARTTLS for outgoing. The username is your full Proton address and the password is the Bridge-generated one, for both servers.

3. 3

   Leave Bridge running

   The local servers exist only while Bridge is open and signed in. If your client shows connection errors, check Bridge first. Bridge has an Open on startup setting if you want it to launch when the computer boots.

Why Proton Mail has no public IMAP server#

Proton encrypts your mail so that Proton's servers cannot read it. Standard IMAP expects the server to hand a client readable messages, and a server that cannot read your mail cannot do that. A public IMAP endpoint would mean Proton holding the keys to your mailbox, which would break the privacy promise the product is built on.

Bridge solves this on your side of the connection. It holds your keys on your computer, fetches the encrypted mail from Proton, decrypts it locally and serves it to your email client on 127.0.0.1. Your client talks to Bridge, and Bridge talks to Proton.

Where Bridge works and where it does not#

Bridge is a desktop application. Proton's Bridge page describes it as an app that runs in the background on your computer, and it does not mention a mobile version. I found no Proton announcement of one, so treat phones and tablets as out of scope for IMAP.

Proton Mail Bridge not working: quick fixes#

Most failures are one of the following. Start at the top.

Using AI Emaily alongside Proton Mail#

Bridge is the supported way to use Proton Mail in a desktop email client. AI Emaily does not connect to Proton Mail.

If your other accounts are Gmail, Outlook or Microsoft 365, iCloud, Yahoo, Fastmail or another IMAP provider, AI Emaily connects them in one inbox and drafts replies from the Personal Context you set. In Copilot you approve every send, and Autopilot adds undo and an audit log. It is a paid app after a 7-day free trial on Pro or Autopilot, and the IMAP connection guide covers the generic provider setup.