Open Source Proton Mail Alternatives Filtered by 'Encrypted Email'

The best open source alternative to Proton Mail is Tuta Mail. If that doesn't suit you, our users have ranked more than 100 alternatives to Proton Mail and nine of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Proton Mail are Posteo, Disroot, Infomaniak kMail and FlowCrypt.

filter to find the best alternatives

Proton Mail alternatives are mainly WebMail Providers, but if you're looking for Email Clients or File Encryption Software you can filter on that. Other popular filters include Free, Open Source and Self-Hosted. These are just examples - use the filter bar below to find more specific alternatives to Proton Mail.

More about Proton Mail

Proton Mail alternatives page was last updated May 14, 2026

Tuta Mail
563 likes
Offers comprehensive encryption for email, calendar, and contacts with zero personal info required. Built on open source, install via Play Store, F-Droid, or APK, with Tor and VPN support. Both free and paid plans; utilizes quantum-resistant encryption ensuring privacy-focused, anonymous usage.
109 Tuta Mail alternatives
Cost / License
Freemium
Open Source (GPL-3.0)
Application types
WebMail Provider
Email Client
Origin
Germany
EU
Platforms
Mac
Windows
Linux
Online
Android
iPhone
iPad
Flathub
F-Droid
Android Tablet
Thunderbird
+1
Is Tuta Mail a good alternative to Proton Mail?

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10comments
Tuta Mail vs Proton Mail Comments

Top Positive Comment
Belsima
May 21, 2018
10
Functions on secure browsers like Klar and Tor.
Advik
Positive commentFeb 1, 2022
3
Tutanota is end-to-end encrypted, as well offers 1 GB mail storage on free plan. The pro plans are cheap compared to protonmail, so it's better for low budget users
Conner Vieira
Positive commentSep 13, 2021
-1
Tutanota has historically been a lot more transparent, and arguably has been more honest about issues and plans
3 of 10 comments
Tuta Mail is Freemium and Open SourceProton Mail is also Freemium and Open Source
Tuta Mail is LightweightProton Mail is not according to our users
Posteo
89 likes
Web- and IMAP-based email service. 4GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.
79 Posteo alternatives
Cost / License
Paid
Open Source
Application types
WebMail Provider
Email Client
Origin
Germany
EU
Platforms
Online
+9
Is Posteo a good alternative to Proton Mail?

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1comment
Posteo vs Proton Mail Comments

John Fastman
Positive commentApr 28, 2018
2
Posteo could be a good Protonmail alternative. It offers email encryption in a similar way: Posteo's people, government surveillance and successful hackers won't get into your email content. It also offers a calendar feature, which protonmail users have been crying out for for years.
Posteo is Paid and Open SourceProton Mail is Freemium and Open Source
Posteo is Security-focusedProton Mail is not according to our users
Disroot
120 likes
Disroot is a platform providing online services based on principles of freedom, privacy, federation and decentralization.
46 Disroot alternatives
Cost / License
Free
Open Source
Application type
WebMail Provider
Origin
Netherlands
EU
Platforms
Online
F-Droid
Is Disroot a good alternative to Proton Mail?

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3comments
Disroot vs Proton Mail Comments

Leonardo Eugenio
Positive commentJun 7, 2019
2
imap smtp support, open source, all free
Guest
Positive commentJul 8, 2019
0
Simple, efficient, you can use it with Tunderbird or other mail client.
Review by a new / low-activity user.
Kris22332
Positive commentSep 3, 2022
-3
Proton is not confidential at all, because it is under the influence of the EU. The best thing you can find for anonymous messaging and file sharing is the Utopia ecosystem (U.IS)
Disroot is Free and Open SourceProton Mail is Freemium and Open Source
Disroot is DecentralizedProton Mail is not according to our users
Ad
Infomaniak kMail
Privacy-focused Swiss email system provides 20 GB free storage, supports custom domains and unlimited storage, syncs contacts and calendars, is ad-free, and is part of a secure productivity suite used by over a million users acro...

https://www.infomaniak.com
Learn More
Infomaniak kMail
48 likes
Privacy-focused Swiss email system provides 20 GB free storage, supports custom domains and unlimited storage, syncs contacts and calendars, is ad-free, and is part of a secure productivity suite used by over a million users across Europe on all devices.
50 Infomaniak kMail alternatives
Cost / License
Freemium
Open Source (GPL-3.0)
Application types
WebMail Provider
Email Client
Origin
Switzerland
Platforms
Online
Android
iPhone
Android Tablet
iPad
F-Droid
+8
Is Infomaniak kMail a good alternative to Proton Mail?
FlowCrypt
17 likes
FlowCrypt (formerly CryptUp) is the easiest PGP encryption for Gmail. It behaves just like standard email, except it's encrypted.
Cost / License
Freemium
Open Source
Origin
United States
Platforms
Android
iPhone
Google Chrome
Brave
Firefox
OpenPGP
+1
Is FlowCrypt a good alternative to Proton Mail?
Forward Email
8 likes
Forward Email is the best email service, encrypted email service, and fastest email service. It supports unlimited domains and aliases for no extra cost. It uses quantum safe ChaCha20-Poly1305 encryption and offers SMTP, IMAP, POP3, email webhooks, email regular expressions...
Cost / License
Freemium
Open Source (MPL-2.0)
Application type
WebMail Provider
Origin
United States
Platforms
Self-Hosted
Online
Is Forward Email a good alternative to Proton Mail?

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1comment
Forward Email vs Proton Mail Comments

linuxplayer
Negative commentJul 7, 2024
1
Needs an existing email to be used for free. You have to pay to create an email.
Forward Email is Freemium and Open SourceProton Mail is also Freemium and Open Source
Swisscows.email
5 likes
Swisscows.email is another product of Swisscows AG. This product offers you secure email traffic. With Swisscows.email you can send your emails encrypted so that absolutely no one can read them. The service is comparable to a letter that is protected from prying eyes in an...
57 Swisscows.email alternatives
Cost / License
Paid
Open Source
Application types
WebMail Provider
Email Client
Origin
Switzerland
Platforms
Online
iPhone
iPad
Android
Android Tablet
+6
Is Swisscows.email a good alternative to Proton Mail?
GPGMail
11 likes
GPGMail is a PGP plugin for Apple Mail. It brings the functionality to sign, verify, encrypt and decrypt mails using the OpenPGP standard.
Cost / License
Paid
Open Source
Origin
Germany
EU
Platforms
Mac
GPGTools
Apple Mail
Is GPGMail a good alternative to Proton Mail?
WebPG
2 likes
WebPG is a free, open source suite of tools to bring OpenPGP (GnuPG/PGP, gpg, gnupg) to the browser, in an effort to make cryptographic methods usable, safe and accessible to the common man.
Cost / License
Free
Open Source
Application type
File Encryption Software
Alerts
Discontinued
Platforms
Mac
Windows
Linux
Google Chrome
Thunderbird
SeaMonkey
Chromium
Firefox
OpenPGP
+1
Is WebPG a good alternative to Proton Mail?

9 of 9 Proton Mail alternatives

Open Source Proton Mail Alternatives Filtered by 'Encrypted Email'

Alternatives list

Tuta Mail

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Tuta Mail vs Proton Mail Comments

Posteo

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Posteo vs Proton Mail Comments

Disroot

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Disroot vs Proton Mail Comments

Infomaniak kMail

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FlowCrypt

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Forward Email

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Forward Email vs Proton Mail Comments

Swisscows.email

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GPGMail

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WebPG

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