Proton Mail SMTP and IMAP settings
How to connect Proton Mail over SMTP/IMAP, which requires the paid Proton Mail Bridge app.
Outgoing mail (SMTP)
| SMTP server | 127.0.0.1 (Proton Mail Bridge, local) |
|---|---|
| Port | 1025 (STARTTLS) |
| Username | The address and password shown in the Bridge app |
| Password | See authentication note below |
Incoming mail (IMAP)
| IMAP server | 127.0.0.1 (Proton Mail Bridge, local) |
|---|---|
| Port | 1143 |
| Security | STARTTLS |
Authentication
Proton does not expose public SMTP/IMAP. You must run Proton Mail Bridge (paid plans only), which exposes a local server on 127.0.0.1 and generates app-specific credentials. There is no way to send through Proton from a cloud server without the Bridge.
Good to know
- Because the Bridge runs locally, Proton is generally not suitable for server-side cold-email sending.
How to set up Proton Mail in your email tool
- Open your email client or sending tool and add a new account.
- For incoming mail, choose IMAP and enter server 127.0.0.1 (Proton Mail Bridge, local), port 1143 (STARTTLS).
- For outgoing mail, enter the SMTP server 127.0.0.1 (Proton Mail Bridge, local) on port 1025 (STARTTLS).
- Set the username to the address and password shown in the bridge app, and use the password described in the authentication note above.
- Save the account and send a test email to confirm it works.
Connecting is the easy part. Landing in the inbox is not.
Once Proton Mail is connected you can send, but whether your cold email reaches the inbox depends on SPF, DKIM, and DMARC authentication, your sender reputation, and proper domain warmup. Scheduler Zero handles warmup and deliverability so your emails actually land.