Proton Mail is the encrypted email service from Proton AG. Learn how Proton Mail protects your mail and how Bridge connects desktop clients. See how to move mail in or out.
Proton Mail is an encrypted email service from Proton AG in Switzerland. Scientists who met at CERN founded Proton in 2014 and Proton Mail stores your mail with zero access encryption.
Desktop clients reach Proton Mail through Bridge on a paid plan. The Export Tool saves your mail as EML files and Easy Switch imports mail from other providers.
Save your recovery phrase before you need it. Data stays locked after a password reset until you use a recovery method.
Proton Mail is an encrypted email service from Proton AG in Switzerland. Proton Mail keeps your messages on Proton servers in a form that Proton cannot read.
Proton Mail works as a normal inbox. You read and send mail as in any other service while the encryption happens in the background.
You sign in on the web or in a mobile app. Desktop clients like Outlook and Thunderbird reach Proton Mail through a free helper called Bridge.
People search for Proton Mail for three reasons. Some want to know how the encryption works. Some want mail in a desktop client and others need to export or import mail.
Proton Mail does not give you a mail file on your own disk by default. Your mail stays online until you export it or let Bridge keep a cache of it.
This page covers who makes Proton Mail and how the encryption works. You also learn what Bridge does and which export formats exist.
Proton Mail is an email service from Proton AG with zero access storage. Bridge links it to desktop clients and the Export Tool saves mail as EML files.
.eml files with .json metadataComparing private mail services? Hushmail and Zoho Mail take different approaches. See the full list of email application guides.
Proton AG makes Proton Mail. Scientists who met at CERN founded Proton in 2014 and the company is based in Geneva.
Proton AG makes Proton Mail. The Proton ownership page says the company is based in Switzerland with headquarters in Geneva and its main datacenter in Zurich.
The same page says scientists who met at CERN founded Proton in 2014. The Proton anniversary post names Andy Yen as founder and CEO and says he worked as a research scientist at CERN.
The anniversary post says more than 10,000 community members raised over $500,000 in 2014. Proton moved from donations to a freemium subscription model in 2016.
The ownership page names the Proton Foundation as the primary shareholder. It describes the Foundation as a Swiss nonprofit.
Employees hold most of the remaining shares. FONGIT and Proton users also hold shares according to the same page.
Proton announced Proton Mail 2.0 on 13 August 2015. The Proton Mail 2.0 announcement says the entire webmail client became open source and that cryptography had been open from day one.
The anniversary post later says Proton has made all of its apps open source. Neither page names the licenses.
| Date | Fact | Source |
|---|---|---|
| 2014 | Proton founded by scientists from CERN | Proton ownership page |
| 2014 | Over $500,000 raised from backers | Proton anniversary post |
| 13 Aug 2015 | Proton Mail 2.0 opens webmail code | Proton announcement |
| 2016 | Donations give way to freemium | Proton anniversary post |
| 31 Jan 2022 | New Bridge with local cache | Proton Bridge post |
Proton Mail now sits inside a wider Proton account. The recovery guide says Proton also encrypts calendar and drive and password data.
Want other privacy minded providers? GMX Mail and Yandex Mail show how different regions build mail.
Yes. Proton keeps current guides for Proton Mail and offers a free tier. Bridge needs a paid plan and POP3 is not offered.
Yes. Proton publishes current support pages for Proton Mail and Bridge and for the Export Tool. FileFix found no page that announces an end of service.
Proton Mail has a free tier. The anniversary post says all basic Proton services remain free.
Proton Mail asks for a paid plan only when you need Bridge or extra addresses. Everyday web mail works on the free tier.
A free account gets one primary email address according to the Proton address and alias page. Paid plans add more addresses and custom domains.
Bridge is a paid feature. Proton says the app is available only with a paid plan that includes Proton Mail. FileFix lists no prices because Proton changes them.
Password protected emails work on every plan including the free one. Any recipient can read them without a Proton account.
Free accounts can face deletion after a long stretch without a sign in. The Proton inactive accounts page words the interval in two ways. Read the current page for the exact period.
Proton sends reminder emails 30 days and 15 days and 7 days before the scheduled deletion. Deletion removes emails and contacts and calendars for good.
Paid accounts follow another rule. Proton says it never deletes a paid account because of the inactivity.
No. The Proton IMAP and SMTP page states that Proton does not offer POP3 support. Bridge handles the connection for a desktop client instead.
| Item | What the source says | Source |
|---|---|---|
| Service status | Current guides for Mail and Bridge | Proton support pages |
| Basic services | Remain free | Proton anniversary post |
| Bridge | Paid plan only | Proton Bridge page |
| POP3 | Not offered | Proton IMAP page |
| Paid inactivity deletion | Never | Proton inactive accounts page |
| Prices | Not listed here | Held back on purpose |
Check your own plan before you plan a desktop setup. A mail client that needs POP3 will not connect directly to the service.
Proton Mail stores mail with zero access encryption and sends Proton to Proton mail end to end encrypted. Subject lines stay unencrypted.
Proton Mail uses two kinds of protection. Zero access encryption covers mail stored on Proton servers. End to end encryption covers mail that moves between the right people.
The Proton encryption guide says zero access means nobody else can read your emails and that includes Proton. Message bodies and attachments get that shield.
Proton Mail applies the same protection to contacts and calendar events. The recovery guide lists them as encrypted data next to emails.
The messages between two Proton Mail users are always end to end encrypted. Messages to other providers travel over TLS and the other provider can read them.
Mail from another provider arrives over TLS first. Proton then stores it with zero access encryption.
Subject lines are not end to end encrypted. Proton says PGP puts the subject in an open header packet. Proton keeps it that way so mail systems work together.
Proton recommends generic subject lines. Treat the subject like a postcard and keep the secrets in the body.
Use a password protected email for the outside reader. The Proton page on password protected emails says the sender sets a message password and an optional hint in the composer.
The email expires after 28 days by default and 28 days is the maximum. The recipient opens it in a browser and can reply up to five times.
Share the password in the other channel. Your own reply is not encrypted by default once the recipient sends an answer.
Yes. Proton states that Proton Mail follows the OpenPGP standard. You can export your Proton Mail PGP key so a contact outside Proton can use PGP with you.
| Term | Plain meaning | Source |
|---|---|---|
| Zero access | Stored mail that Proton cannot read | Proton encryption guide |
| End to end | Mail only the sender and reader can open | Proton encryption guide |
| TLS | Protects mail in transit to other providers | Proton encryption guide |
| Password protected | End to end mail for outside readers | Proton password page |
| OpenPGP | Standard that Proton Mail follows | Proton encryption guide |
Compare this with Hushmail if you weigh other encrypted services. The what a file format is background helps when you meet PGP and EML terms.
Proton Mail defaults to proton.me and also offers protonmail.com and pm.me. Hide my email aliases and custom domains add more addresses.
Proton Mail gives you an address on a Proton domain. The Proton address and alias page says proton.me is the default for new accounts.
You can choose protonmail.com at signup. Paid plans also allow pm.me and extra protonmail.com addresses.
Protonmail.ch is the original domain. People who joined before 2016 can see it as their default.
A hide my email alias is a random address that forwards to your mailbox. Senders never see your real address.
Free and Mail Plus users can create up to 10 of them. Higher plans like Proton Unlimited allow unlimited aliases.
Plus aliases need no setup. Add a plus sign and a word after your username and you get name+bills@proton.me.
Yes on any paid Proton Mail plan. You can create addresses like contact@yourdomain.com. Paid plans also let you add at least 10 extra addresses.
Bridge needs one more step for custom domains. Thunderbird will not detect the server settings and you must enter them by hand.
| Option | Who can use it | Source |
|---|---|---|
| proton.me | Default for new accounts | Proton address page |
| protonmail.com | Choice at signup | Proton address page |
| pm.me | Paid plans | Proton address page |
| Hide my email aliases | Up to 10 on Free and Mail Plus | Proton address page |
| Custom domain | Any paid plan | Proton address page |
The aliases help when you sign up for a newsletter. A throwaway alias keeps the main Proton Mail address out of the marketing lists.
Many clients treat an alias as a separate identity. The Thunderbird guide from Proton shows how to add one under Manage Identities.
Install Proton Mail Bridge on a paid plan and sign in. Then add your address to Thunderbird or Outlook with the Bridge password.
Proton Mail Bridge is a desktop app that connects a mail client to your Proton Mail account. The Proton Bridge page says Bridge creates a local mail server on your computer.
Your client talks to that server over IMAP and SMTP. Bridge encrypts and decrypts the messages in the background.
The list of clients that Bridge supports names tested clients per system. Windows gets Thunderbird and Outlook 2010 through 2021. macOS gets Thunderbird and Apple Mail and Outlook.
Linux gets Thunderbird only. Proton says Bridge should work with other clients but warns about crashes and bugs because every client treats IMAP a little differently.
The IMAP page says Bridge exists for macOS and Windows and Linux. It does not exist for a mobile device.
FileFix found no minimum system versions on the Proton pages it could load. Check the Bridge install guide first.
The Proton Thunderbird guide for Bridge says Bridge uses a certificate that exists only on your device. No certificate authority signs it so Thunderbird asks you to confirm an exception.
Thunderbird confirms the SMTP certificate only after you send a test message. If an error shows up you dismiss the error and send again.
Combined addresses mode is the default and puts all your addresses in one mailbox. The Bridge installation guide explains the Split addresses switch for people who want separate mailboxes.
Compare clients first because Proton Mail works with several. Mozilla Thunderbird and Apple Mail have their own FileFix guides.
Proton Mail stores your mail on Proton servers. Bridge adds an encrypted local cache and your client or the Export Tool can write copies to disk.
Proton Mail keeps your mail on Proton servers with zero access encryption. Nothing sits on your disk until you use a client or an export.
Proton announced a new Bridge on 31 January 2022. The Proton post on the new Bridge says the main change is a local cache that now holds full message bodies.
The post says Bridge stores those messages encrypted on your device. It also says you can move the cache in Advanced settings.
An older Proton article on the Bridge security model says Bridge ignores connections that do not come from the same computer. Treat that article as background because the cache came later.
Proton Mail never forces a local copy on you. The choice to cache or to export belongs to you.
Your client holds its own copy once Bridge hands the mail over. The Proton page on importing and exporting emails says Bridge stores downloaded emails locally and that you can export them with the client.
Every client uses its own storage. Thunderbird writes MBOX files while Microsoft Outlook uses PST files and OST files.
The Proton Mail Export Tool writes plain EML files and JSON files to a folder. The default location creates a folder named after your username.
The Proton guide does not say those files are encrypted. Store them somewhere safe.
| Place | What it holds | Source |
|---|---|---|
| Proton servers | Mail with zero access encryption | Proton encryption guide |
| Bridge cache | Encrypted message copies on your device | Proton Bridge post |
| Client store | The mail copy your client builds | Proton import and export page |
| Export folder | EML files and JSON metadata | Proton Export Tool guide |
| Cache path | Not listed on the pages FileFix loaded | Not verified |
Use the Proton Mail Export Tool to save all emails as EML files with JSON metadata. One message exports from its three dot menu.
Proton Mail gives you three ways to take your mail out. The Proton page on importing and exporting emails lists them. The right route depends on whether you need all mail or one message.
The Proton Mail Export Tool guide says the tool saves emails as EML files with metadata in JSON files. It works from the command line on Windows and macOS and Linux.
proton-mail-export-cli.You cannot pause an export and continue later. A large inbox or a slow connection can take minutes or hours.
It exports Proton Mail emails only. Calendar events and Drive files and Pass items are not included.
The guide does not say how labels or folders appear in the export. FileFix keeps that question open until Proton documents it.
The guide lists Windows 10 and macOS 10.15 on Intel and macOS 11.0 on Apple Silicon. It also lists Ubuntu 20.04 LTS.
Open the message and select the three dot More icon below the sender details. Choose Export and select a location.
Yes. Bridge with Thunderbird saves a chosen set of Proton Mail messages as EML. Proton says this route fits a specific folder while the Export Tool fits backups.
Open Search Messages and set your filters in Thunderbird. Enable the server search option and save the result as a folder. That saved search lives only in Thunderbird.
| Route | Output | Source |
|---|---|---|
| Export Tool | EML files with JSON metadata | Proton Export Tool guide |
| Three dot Export | One message | Proton import and export page |
| Bridge and Thunderbird | EML files from chosen messages | Proton MBOX and EML guide |
| MBOX output | Not mentioned by the Export Tool page | Not verified |
Want the file details? Read the EML files guide for what sits inside a message file.
Use Easy Switch for Gmail or Yahoo Mail or Outlook accounts. Use Bridge with Thunderbird and ImportExportTools NG for EML and MBOX files.
Proton Mail offers two main import routes. Easy Switch pulls mail from another provider. Bridge with Thunderbird takes EML and MBOX files you already hold.
The Easy Switch guide says Easy Switch moves emails from any IMAP based provider. The page names Gmail and Yahoo Mail and Microsoft Outlook.
Calendars and contacts depend on the provider. The page confirms Yahoo Mail offers all three and Outlook offers emails and calendars.
You can transfer from two email accounts at once and only one transfer per account. Imports start with the most recent messages in the mailbox.
Import ranges are all messages and the last 12 months and the last 3 months and the last month. Long used accounts can take days.
Folder names over 100 characters or more than 2,000 folders can force you to adjust settings. Proton Mail supports three folder levels and reorganizes deeper trees.
The Proton guide to MBOX and EML with Bridge covers this route. Proton says it suits providers without IMAP and single folders while the Export Tool and Easy Switch suit backups and migrations.
Raise the mailnews.tcptimeout setting in the Config Editor so large imports keep the connection. Import in batches of 100 to 500 messages according to Proton.
Proton Mail limits folders to three levels so plan the tree before you import. A flat layout moves with less trouble.
The Proton guide for moving from Outlook lists Easy Switch and mail forwarding and Bridge. It does not mention PST files and FileFix found no Proton page that does.
Read about PST files and Microsoft Outlook if your data sits there.
| Route | Best for | Source |
|---|---|---|
| Easy Switch | Gmail, Yahoo Mail, Outlook and IMAP | Proton Easy Switch guide |
| Bridge and add on | EML and MBOX files | Proton MBOX and EML guide |
| Export Tool restore | Mail its own export saved | Proton Export Tool guide |
| PST import | No Proton page found | Not verified |
Use a recovery phrase or recovery file or old password to open data. A recovery email or phone resets the password only.
Proton Mail splits recovery into two stages. You first reset the password and then restore access to your encrypted data. The Proton data recovery guide explains both.
A password reset can leave your encrypted data locked. Locked data appears as random characters or as a message that it is not available or could not be decrypted.
Emails and contacts and calendar events and Drive files all count as encrypted data. They stay locked until you use a data recovery method.
Find the screen at Settings and then Recovery. Select the notice that says some of your encrypted data is locked. The page says some methods work only once so regenerate any method after you use it.
FileFix found no Proton page that offers a back door. The guide says Proton built it this way so that a person with your recovery email or phone cannot read your mail.
Check your password manager for old passwords. An older password can restore access.
Thunderbird and Bridge must both stay open until the import ends. IMAP imports go one message at a time so they can be slow.
Proton Mail exports EML files with JSON metadata. MBOX files cannot enter Proton Mail directly and must pass through Thunderbird.
Proton Mail publishes no mailbox file format because your mail lives on servers. The formats below come from the Proton support pages.
.eml, one message per file from the Export Tool.json, metadata for every exported messageAn EML file holds one email message as text with headers and body. Read the EML files guide for the layout.
Many clients open EML files. Proton says you can import them into Thunderbird or Outlook.
No. Proton says MBOX files cannot go directly into Proton Mail. Import them into Thunderbird Local Folders first and then copy them across.
The mailbox layout itself is explained in the guide to MBOX files.
Contacts travel as VCF contact files and calendars as ICS calendar files. FileFix found no Proton page that lists the import file types for them.
Easy Switch can carry contacts and calendars from some providers. The Export Tool does not export them.
FileFix could not confirm the exact Bridge ports and the local cache folder. It could not confirm how the Export Tool shows labels either.
Proton Mail lets you export your PGP key for outside contacts. That key is a separate item from the mail files.
Doubt any converter that promises exact results. Test it on a copy and compare message counts.
| File | Role | Source |
|---|---|---|
.eml | One exported message | Proton Export Tool guide |
.json | Metadata for exported mail | Proton Export Tool guide |
.mbox | Import through Local Folders | Proton MBOX and EML guide |
| OpenPGP key | Key for outside contacts | Proton encryption guide |
| Bridge cache | Encrypted local copy | Proton Bridge post |
Mail stores follow common designs. what a file format is is a good starting point. The file format guides cover other formats you will meet.
Try the recovery phrase. Section 10 lists every recovery method.
Check the Bridge password. Section 6 lists the setup steps.
Need a client to pair with Bridge? Read about Mozilla Thunderbird first. Apple Mail covers the built in Mac client.
Is Outlook your daily client? The Microsoft Outlook guide shows where its mail lives. Offline data sits in PST files and OST files.
Want to see how other services handle privacy? Hushmail and Zoho Mail use other models. GMX Mail and Yandex Mail show regional providers.
Holding saved messages from a program that closed? Opera Mail and Windows Live Mail keep mail on disk. SeaMonkey and Sylpheed do the same.
Curious about server side mail? Exchange Server and Zimbra Mail host mailboxes for companies.
Dealing with calendar or contact files? ICS calendar files and VCF contact files cover them. MAB address books and OLK files come from other clients.
Browsing wider? Scan topics in the FileFix category index or open the FileFix home page. Computer faults sit in the Windows error guides. Send us the file details when your Proton Mail export behaves in a way this page leaves unanswered.