Proton Mail SMTP: Proton Bridge or SMTP submission (smtp.protonmail.ch)
Proton Mail has no plain SMTP login. Paid plans use Proton Mail Bridge (local 127.0.0.1:1025) or, on Business/Professional plans, an SMTP submission token against smtp.protonmail.ch port 587. Setup, limits and what free accounts can do.
Proton Mail outgoing mail server:
127.0.0.1, port <code>1025</code> (STARTTLS (local Bridge)) or <code>587</code> (STARTTLS), username = Bridge: the address shown in the Bridge app — Submission: the address the token was created for, password = Bridge: the Bridge-generated password.
Proton Mail SMTP settings at a glance
| Outgoing (SMTP) host | 127.0.0.1 (Proton Mail Bridge) — or smtp.protonmail.ch for SMTP submission tokens |
|---|---|
| Ports & encryption |
1025 — STARTTLS (local Bridge) <em>(Bridge default; shown in the Bridge app)</em>587 — STARTTLS <em>(smtp.protonmail.ch with a submission token)</em> |
| Username | Bridge: the address shown in the Bridge app — Submission: the address the token was created for |
| Password | Bridge: the Bridge-generated password (not your Proton password) — Submission: the SMTP token |
| Authentication | Proton end-to-end encrypts mailboxes, so a normal SMTP login cannot exist. Bridge runs on your machine and speaks SMTP locally; SMTP submission tokens (Proton Business / Professional plans) let a server or device send through smtp.protonmail.ch without Bridge. |
How to set up Proton Mail SMTP
- Desktop client: install Proton Mail Bridge, sign in, open the account's "Mailbox configuration" — it shows the local SMTP host (127.0.0.1), port (1025), username and generated password.
- Server/device: Proton settings → Mail → IMAP/SMTP → SMTP submission (available on business plans) → generate a token for the address.
- App settings: host smtp.protonmail.ch, port 587, STARTTLS, username = the address, password = the token.
Sending limits
- Free plan: no Bridge, no SMTP — web and apps only, 150 messages per day.
- Paid plans: Bridge for desktop clients; submission tokens are a business-plan feature with per-plan daily limits.
- Sending is meant for personal/business correspondence, not application bulk mail.
Things that catch people out
- Bridge only works while it is running on the same machine — it is not for servers.
- The From address must be a Proton address or a custom domain configured in Proton.
Common Proton Mail SMTP errors
| Server reply | Meaning | Fix |
|---|---|---|
535 5.7.0 Authentication failed | Proton account password used, or token/plan not enabled. | Use the Bridge password or an SMTP submission token. |
Connection refused on 127.0.0.1:1025 | Bridge is not running. | Start Bridge and re-check the port it shows. |
More codes: 535 authentication failed, 550 relay denied, 554 rejected as spam, connection timed out — or all SMTP error codes.
When Proton Mail is not enough for your app
When a provider caps you or blocks a port, point the same app at QueenSMTP instead: host smtp.queensmtp.com, port 587 (STARTTLS) or 465 (SSL), your SMTP username and password from the dashboard. $5/year plus $0.10 per 1,000 emails, 100 free a day to test.
Get SMTP credentials — free to test Test Proton Mail nowRelated settings
Proton Mail SMTP — questions
Not with a plain login. Paid plans use Proton Mail Bridge locally; Business plans can create SMTP submission tokens for smtp.protonmail.ch on port 587. Free plans have no SMTP access.
Only with an SMTP submission token on a business plan, and within Proton's limits. For website and application mail a dedicated SMTP relay is the normal choice.
Related Guides
Continue learning with these related articles