Email Settings GuideQuick answer: Proton has no public mail server. You install Proton Mail Bridge on your computer. It runs a local server your email app connects to. Incoming IMAP is 127.0.0.1 port 1143, outgoing SMTP is 127.0.0.1 port 1025, both STARTTLS. The username is your full address and the password is the one Bridge generates, not your Proton password. Three things to know: Bridge needs a paid plan, there is no POP3, plus Bridge must be running for mail to sync.
What Changed Recently#
Email providers change login rules more often than server addresses. Proton keeps its own apps and its Bridge app moving quickly. Here is where Proton Mail stands for email client setup in 2026.
Latest update
Outlook, Apple Mail and Thunderbird only work through Bridge. Proton does not expose IMAP or SMTP on the internet. Bridge runs on your computer and hands your email app a local server. It needs a paid plan. How Bridge works.
Earlier change
Default ports are 1143 for IMAP and 1025 for SMTP. If another app already uses one, Bridge lets you bump the number, so always read the exact port from your Bridge window. Where to find your values.
Earlier change
proton.me is the current address, protonmail.com still works. Older @protonmail.com, @protonmail.ch and @pm.me addresses all use the same Bridge setup as @proton.me.
127.0.0.1 ports 1143 and 1025 with the Bridge password. Free plans use the Proton web and mobile apps only.
Before You Begin#
Two Proton facts sink most setups before a single port is typed. Sort both first.
1. You need a paid Proton plan
Proton Mail Bridge is the only way to use IMAP or SMTP. Bridge needs a paid plan such as Mail Plus or Proton Unlimited. Free accounts cannot connect any external email app at all.
Where: Free or paid check below →
2. Bridge must be installed and running
Your email app connects to Bridge, not to Proton, so Bridge has to be open on the same computer. If Bridge is closed, mail stops moving. There is no Bridge on phones, only on Windows, Mac and Linux.
Where: Bridge setup below →
About Proton Mail#
Proton Mail is a Swiss end-to-end encrypted email service run by Proton AG, started in 2014 by scientists from CERN and now one of the largest private email providers in the world.
Because every mailbox is encrypted so that not even Proton can read it, a normal email app cannot open it. That is why Proton built Proton Mail Bridge, a desktop app that decrypts and encrypts on your own machine and gives your email client a local server to use. ProtonMail was renamed Proton in 2022 and moved to the proton.me domain, though older addresses still work.
| Service Name | Proton Mail |
| Run By | Proton AG, Switzerland |
| Launched | 2014, by CERN scientists |
| Email Domains | proton.me, protonmail.com, pm.me |
| Webmail URL | mail.proton.me |
| Protocols | IMAP and SMTP via Bridge, no POP3 |
| Client Access | Bridge app, paid plans only |
| Free Storage | 1 GB, 150 messages a day |
@proton.me, @protonmail.com, @protonmail.ch, @pm.me and custom domains all connect through the same local Bridge server. Your address only changes the username, never the 127.0.0.1 server.
Proton Mail Login#
Free plans and anyone who prefers the web read mail in a browser. The official pages are:
Webmail
mail.proton.me (webmail)
Account Security
account.proton.me (account and plan)
Two Password Mode
Proton can use a separate mailbox password on top of your login password. If yours does, that mailbox password is what unlocks your mail. It is not recoverable if lost, so keep it safe.
You Need Proton Mail Bridge#
This is the part that catches everyone. Proton encrypts your mailbox so completely that a normal email app cannot read it. Bridge is the fix. It runs on your computer, decrypts and encrypts locally, then gives your email app a small server at 127.0.0.1 to connect to.
Can you use it on a free plan?
No. Bridge needs a paid plan. On a free account your only options are the Proton website and the Proton mobile app.
Only need to read Proton on your phone? You do not need Bridge at all. The Proton Mail app handles the encryption for you.
Proton IMAP Settings (via Bridge)#
With Bridge running, point your email app at the local server below. Bridge shows you these exact values in its window, so if a port differs, trust the Bridge window over any guide:
| IMAP Server | 127.0.0.1 (localhost) | |
| Port | 1143 (default, check Bridge) | |
| Encryption | STARTTLS (Bridge can switch to SSL) | |
| Username | Your full address, for example you@proton.me | |
| Password | The Bridge password, not your Proton password | |
| Authentication | Required |
Proton and POP3#
Short version: there is no POP3 on Proton. Bridge speaks IMAP and SMTP only, so every setup on this page uses IMAP to receive. If an old guide gives you a Proton POP3 server, it is wrong.
Proton SMTP Settings (via Bridge)#
127.0.0.1 on the port your Bridge window lists, default 1025 with STARTTLS. If a guide tells you to enter a proton.me or protonmail.com SMTP host, it predates Bridge.
Outgoing mail also goes through Bridge on the same local server. If you can read mail but not send, the port or the Bridge password is usually the cause:
| SMTP Server | 127.0.0.1 (localhost) | |
| Port | 1025 (default, check Bridge) | |
| Encryption | STARTTLS (Bridge can switch to SSL) | |
| Username | Your full Proton address | |
| Password | The Bridge password, same as incoming | |
| Authentication | Required. Tick "My outgoing server requires authentication" and reuse the Bridge login. |
Check Proton IMAP Settings Online#
You don't need to download anything to check Proton IMAP settings online. This page is the lookup, with the Bridge values verified and copyable. Remember the real server is always 127.0.0.1 on your own machine. Type your address for a quick check:
Does my email address use these settings?
Runs in your browser only. Your address is never sent anywhere or stored.
Want to check the account first? Sign in at Proton webmail. If webmail works but your email app does not, the cause is almost always Bridge, either it is not running or you used your Proton password instead of the Bridge password.
Look Up IMAP Settings for Any Email Domain#
This page covers Proton. For any other address, including a business domain on a normal mail host, our free lookup database imapsettings.com returns the incoming and outgoing servers for any domain in one step.
imapsettings.com
Complete email settings database, by Univik
Enter any email address and get the incoming and outgoing server settings for that domain in 1 step:
Your address is used only to find the settings for that domain. Nothing is stored or shared.
Your Bridge Password#
The single most common Proton mistake is typing your Proton account password into your email app. That will always fail. Bridge makes its own password for each address. Here is which password goes where:
| Where you sign in | Proton password | Bridge password |
|---|---|---|
| proton.me website and Proton apps | ✓ Works | ✗ Not used |
| Outlook, Apple Mail, Thunderbird | ✗ Rejected | ✓ Required |
| Univik Email Backup and other tools | ✗ Rejected | ✓ Required |
| Proton Mail app on your phone | ✓ Works | No Bridge on mobile |
How to Find Your Bridge Values
- Install Proton Mail Bridge from your Proton account, then sign in with your Proton login inside Bridge.
- Open the mailbox details in Bridge for the address you want to connect.
- Read the server, ports, username and password that Bridge shows. The password is a long code Bridge made for you.
- Copy that Bridge password into your email app as the password for both incoming and outgoing.
- If a port is taken, change it in Bridge under Settings, then Advanced settings, then Default ports. Update your app to match.
Set Up Proton in Email Clients#
Bridge must be installed and running first. Then point each app at 127.0.0.1 with the Bridge ports and Bridge password. Phones are different, there is no Bridge on mobile. Jump to your app:
Outlook (Windows and Mac)
- Open Outlook → File → Add Account [new Outlook: Settings → Accounts → Add account].
- Open Bridge first, then in Outlook enter your Proton address, open Advanced options and check "Let me set up my account manually".
- Choose IMAP and enter
127.0.0.1port1143for incoming and127.0.0.1port1025for outgoing, both STARTTLS. - Use the Bridge password from the Bridge window, not your Proton password, when Outlook asks.
- Finish and send yourself a test. If Outlook warns about the Bridge certificate, accept it once.
Apple Mail (macOS)
- Open Mail → Settings → Accounts → Add Account.
- Choose Other Mail Account, since Proton is not in the built in list.
- Enter your name, Proton address and the Bridge password, then continue.
- Set both incoming and outgoing to
127.0.0.1with the Bridge ports. Accept the Bridge certificate if asked. - Enable Mail in the checkbox list and finish.
iPhone and iPad
- Open Settings → Apps → Mail → Mail Accounts → Add Account.
- There is no Bridge on iPhone. The built in Mail app cannot connect to Proton.
- Install the Proton Mail app from the App Store instead.
- Sign in with your Proton login. The app handles all the encryption for you, no server settings needed.
- Turn on notifications so new mail arrives like any other app.
Android
- There is no Bridge on Android either, so third party mail apps cannot open Proton.
- Install the Proton Mail app from Google Play.
- Sign in with your Proton login. No 127.0.0.1, no ports, the app does the encryption itself.
- Use Bridge on your computer only if you also want Proton in a desktop client.
- Finish setup and pull down to sync your inbox.
Thunderbird
- Open Thunderbird → Account Settings → Account Actions → Add Mail Account.
- Start Bridge, then in Thunderbird enter your name, Proton address and the Bridge password, then select Continue.
- Bridge configures Thunderbird for you. Newer Bridge versions add the account automatically. Confirm IMAP is selected.
- If not, choose Configure manually and enter
127.0.0.1with the Bridge ports for both servers. - Select Done. Folders sync on first open.
Proton Webmail Settings#
Server settings connect your apps. These control how Proton Mail itself behaves. Find them at mail.proton.me under the gear icon, then All settings.
Signature
Settings, then Identity and addresses, then Signature. A signature here shows in Proton apps. Outlook and Thunderbird keep their own separate signature.
Vacation Auto Reply
Settings, then Auto-reply. Set start and end dates so it turns off by itself. It runs on Proton, so it replies even when your computer and Bridge are off.
Filters and Folders
Settings, then Filters. Rules here run on Proton, so mail is sorted before Bridge or your phone sees it. Client side rules only run while that app is open.
Spam and Blocked Senders
Settings, then Filters, then Spam, block and allow list. Add addresses or whole domains. Blocked senders skip the inbox.
Bridge vs the Proton Apps#
| Feature | Bridge + desktop client | Proton web and mobile apps |
|---|---|---|
| Plan needed | ⚠️ Paid only | ✅ Works on free too |
| Works on phone | ❌ Desktop only | ✅ iOS and Android apps |
| Use Outlook or Thunderbird | ✅ Yes, this is the point | ❌ Not possible |
| Computer must be on | ⚠️ Bridge has to run | ✅ No, Proton hosts it |
| Local backup to PST or MBOX | ✅ Via a backup tool | ❌ Export only |
| Best for | Desktop client users, archiving | Everyday reading, phones, free plans |
Proton Sending and Storage Limits#
Proton throttles sending to stop abuse. The numbers change by plan. Know them before you bulk forward or migrate a mailbox:
| Messages per day (free) | 150 |
| Sending on paid plans | Throttled, roughly 100 to 200 an hour |
| Storage (free) | 1 GB, 1 address |
| Storage (Mail Plus) | 15 GB, up to 10 addresses |
| Storage (Unlimited) | 500 GB, up to 15 addresses |
| Client access (IMAP and SMTP) | Paid plans only, through Bridge |
Troubleshooting Proton and Bridge#
Find the exact error your email app shows, then apply the fix:
| Error you see | What it means | Fix |
|---|---|---|
| Cannot connect to 127.0.0.1 | Bridge is not running | Open Proton Mail Bridge and leave it running. Your email app talks to Bridge, so it must be on. |
| Port already occupied | Another app took 1143 or 1025 | In Bridge, go to Settings, Advanced settings, Default ports and bump the number. Then match the new port in your email app. |
| Password rejected or wrong password | You used your Proton password | Copy the Bridge password from the Bridge window instead. Your Proton login does not work in email apps. |
| Cannot add IMAP account at all | You are on a free plan | Bridge needs a paid plan. Free accounts use the Proton web and mobile apps only. |
| Certificate not trusted warning | Bridge uses a local certificate | Accept or trust the Bridge certificate once. It secures the link between your app and Bridge on your own machine. |
Reader Reported Fixes
Two fixes that come up again and again in Proton Mail Bridge setups, beyond the error table above.
Let Bridge start with your computer. If mail stops syncing every time you reboot, turn on the option to launch Bridge on startup in its settings. Since your email app depends on Bridge, having it open in the background keeps everything flowing without you thinking about it.
After changing a port, update the client too. If you bumped the IMAP or SMTP port in Bridge to fix a conflict, your email app still points at the old number. Edit the account's server settings and enter the new port from the Bridge window, then test again.
Moving to or from Proton?#
Coming into Proton from Gmail or Outlook? Proton has a built in importer called Easy Switch that pulls your old mail, contacts and calendar into Proton over a secure link. You do not need Bridge for that, it runs inside Proton.
Leaving Proton for another service? That is where Bridge earns its keep. Run Bridge, then point a migration tool at 127.0.0.1 to copy every folder out to Gmail, Microsoft 365 or anywhere else.
Want a copy you fully control? Back up the mailbox through Bridge to PST, MBOX, EML or PDF. Because Proton is encrypted, Bridge is the only way to get a standard offline archive.
Copying folder by folder? The Univik Email Migration Tool connects to Bridge on 127.0.0.1 for the Proton side and your other account for the destination, then copies every folder across.
Rather not do it yourself? Our Email Migration Services team plans and runs the whole transfer for you and verifies every folder arrived.
Use These Settings in Univik Email Backup#
Because Proton is encrypted, the only way to make a standard local backup is through Bridge. With Bridge running, Univik Email Backup connects to 127.0.0.1 and saves everything as PST, MBOX, EML or PDF files you keep forever.
- Download Univik Email Backup and install it on Windows.
- Start Bridge, then choose IMAP as the source and enter
127.0.0.1with your Bridge port. - Sign in with your full Proton address and the Bridge password, not your Proton password.
- Confirm the server details:
127.0.0.1with the Bridge port and STARTTLS, from the IMAP table above. - Pick a saving format and folder, then start the backup. Large mailboxes download in the background.
Univik Tools That Use These Settings#
Many people land here while migrating or archiving a mailbox. All 3 tools use the same IMAP settings from this page:
Email Backup
Connect through Bridge to save your complete Proton mailbox as PST, MBOX, EML or PDF you keep offline.
Email Backup Tool →
Email Migration Tool
Copy every folder from Proton, via Bridge, straight into Gmail, Microsoft 365 or any other account.
Email Migration Tool →
Email Converter Tool
Already have MBOX, EML or OST files from an old export? Convert them to PST, PDF or any format your new app opens.
Email Converter Tool →Prefer to hand the whole migration to experts?
If server settings and app passwords feel like too much, you don't have to learn them. Univik's migration team handles the complete project: planning, transfer, verification and a report showing every folder made it. Since 2013, for single mailboxes up to full company moves.
Email Settings Glossary#
IMAP
Internet Message Access Protocol. Reads mail from the server. On Proton it runs through Bridge on 127.0.0.1 so your desktop client stays in sync.
POP3
Post Office Protocol version 3. An older receive method that Proton does not support at all. Use IMAP through Bridge instead, plus a backup tool for local copies.
SMTP
Simple Mail Transfer Protocol. Sends your outgoing mail. On Proton it also goes through Bridge on 127.0.0.1, port 1025 by default.
SSL / TLS / STARTTLS
Encryption for the connection. SSL/TLS encrypts from the start (ports 993, 995, 465). STARTTLS upgrades a plain connection (port 587).
Bridge Password
A code that Proton Mail Bridge generates for each address. You type it into your email app in place of your Proton password. Bridge, not Proton, checks it.
End-to-End Encryption
Mail is scrambled so only you can read it, not even Proton. This is exactly why a normal email app cannot connect and why Bridge exists.
How We Verify These Settings#
Univik builds email backup, migration and converter software since 2013. Our tools connect to Proton through Bridge on 127.0.0.1 every day for thousands of users, the same way your email app does, so a changed port or Bridge behaviour shows up in our logs quickly.
Every value here is confirmed with 3 checks: a live Bridge connection from Univik Email Backup, a comparison against Proton's own Bridge documentation and a real test through a current Bridge install. We re verify after any Proton or Bridge update and at least once a quarter.
Found something that no longer matches what Bridge shows you? Tell us and we will retest and update the page, with the change logged in what changed recently.
Help & Support
Frequently Asked Questions
Incoming is 127.0.0.1 on port 1143 with STARTTLS, served by Proton Mail Bridge on your computer. Sign in with your full address and the Bridge password. The full table is in the IMAP settings section.
Proton encrypts your mailbox so that not even Proton can read it. A normal email app has no way to decrypt that. Proton Mail Bridge runs on your computer, does the decrypting locally, then hands Outlook a plain local server to use. There is no way around Bridge for a desktop client.
No. Bridge needs a paid plan such as Mail Plus or Proton Unlimited. Free accounts cannot use IMAP or SMTP at all, only the Proton web and mobile apps. More on who can use Bridge.
By default IMAP is 1143 and SMTP is 1025, both on 127.0.0.1 with STARTTLS. If another app already uses one, Bridge lets you raise the number under Settings, then Advanced settings. Always read the exact port from your Bridge window rather than assuming.
No. Proton has no POP3 at all. Bridge speaks IMAP and SMTP only, so use IMAP to receive. For a permanent local copy, which is what POP3 was often used for, connect a backup tool to Bridge instead.
The Bridge password, not your Proton login. Bridge makes a separate password for each address and shows it in the Bridge window. If your app keeps rejecting the password, you are almost certainly using your Proton one by mistake.
Run Bridge, then connect a backup tool to 127.0.0.1. Because Proton is encrypted, Bridge is the only route to a standard backup. See how to back up your Proton mailbox as PST, MBOX, EML or PDF you keep offline.
Almost always Bridge. Maybe it is closed, so open it and let it run. Maybe a port it uses got taken by another app and changed. Check what changed recently, confirm Bridge is running, then match the ports in your email app to the Bridge window.
Run Bridge, then an email migration tool connects to 127.0.0.1 for the Proton side with your Bridge password, plus the destination account details for the other. Every folder and date stays intact.
If setting this up feels risky or you have many accounts to move, our managed email migration service does the entire job for you.
Other Email Provider Settings
Summary: Proton Settings at a Glance
- IMAP: 127.0.0.1, port 1143, STARTTLS
- SMTP: 127.0.0.1, port 1025, STARTTLS
- POP3: not supported on Proton
- Username is your full Proton address
- Needs Proton Mail Bridge, a paid plan only
- Password is the Bridge password, not your Proton one
- Bridge must be running for mail to sync
- Ports may shift, always check the Bridge window