The Best Open Source Proton Mail AlternativesTop WebMail Providers & Email Clients like Proton Mail

The best open source alternative to Proton Mail is Tuta Mail. If that doesn't suit you, our users have ranked more than 50 alternatives to Proton Mail and many 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.

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Proton Mail alternatives are mainly WebMail Providers, but if you're looking for Email Clients or Mail Servers 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.
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Alternatives list

  1. Tuta Mail icon

    Tuta Mail

     543 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.

    104 Tuta Mail alternatives

    Cost / License

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • iPad
    • Flathub
    • F-Droid
    • Android Tablet
    • Thunderbird
    Tuta Mail screenshot 1
     
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    10
    Tuta Mail vs Proton Mail Comments
    Top Positive Comment
    Advik
    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
    -1

    Tutanota has historically been a lot more transparent, and arguably has been more honest about issues and plans

    Ada Byron
    Positive
    1

    I use both, ProtonMail is more secure but also more expensive and not as user-friendly. You cannot beat the price of Tutanota for service they provide.

    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
  2. Posteo icon

    Posteo

     88 likes

    Web- and IMAP-based email service. 4GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.

    77 Posteo alternatives

    Cost / License

    • Paid
    • Open Source

    Application types

    Platforms

    • Online
    Drag and drop
     
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    1
    Posteo vs Proton Mail Comments
    John Fastman
    Positive
    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
  4. Disroot icon

    Disroot

     121 likes

    Disroot is a platform providing online services based on principles of freedom, privacy, federation and decentralization.

    45 Disroot alternatives

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Online
    • F-Droid
    Disroot screenshot 1
     
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    3
    Disroot vs Proton Mail Comments
    Leonardo Eugenio
    Positive
    2

    imap smtp support, open source, all free

    Guest
    Positive
    0

    Simple, efficient, you can use it with Tunderbird or other mail client.

    Review by a new / low-activity user.
    Kris22332
    Positive
    -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
  5. Ad
    Screenshot
    Infomaniak kMail icon
    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
  6. Infomaniak kMail icon

    Infomaniak kMail

     45 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.

    46 Infomaniak kMail alternatives

    Cost / License

    Application types

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • F-Droid
    Infomaniak kMail screenshot 1
     
  7. FlowCrypt icon

    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

    Platforms

    • Android
    • iPhone
    • Google Chrome
    • Brave
    • Firefox
    • OpenPGP
    FlowCrypt screenshot 1
     
  8. Kolab Now icon

    Kolab Now

     43 likes

    Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.

    76 Kolab Now alternatives

    Cost / License

    • Paid
    • Open Source

    Application types

    Platforms

    • Online
    • Software as a Service (SaaS)
    • DAVx5
    Kolab Now email
     
  10. Criptext icon

    Criptext

     11 likes

    Finally, an email service that's built around your privacy. Get your @criptext.com email address and see what it's like to have peace of mind and privacy in every email you send.

    Cost / License

    • Free Personal
    • Open Source

    Application type

    Alerts

    • Discontinued

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    Criptext screenshot 1
     
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    1
    Criptext vs Proton Mail Comments
    Guest
    Positive
    3

    Even thought Proton Mail is a good privacy focused email, it still holds both your emails and your keys on their servers. Regarding ownership, Criptext gives the user ownership over their keys, which reside only on the user's devices. It also uses Signal Protocol for encryption which I personally like better than just using pgp.

    Review by a new / low-activity user.
    • Criptext is Free Personal and Open SourceProton Mail is Freemium and Open Source
  11. Zero Email icon

    Zero Email

     6 likes

    Zero is an open-source AI email solution that gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers. Our goal is to modernize and improve emails through AI agents to truly modernize emails.

    Cost / License

    • Free
    • Open Source (MIT)

    Application type

    Platforms

    • Online
    • Self-Hosted
    • Docker
    Zero Email screenshot 1
     
  12. Swisscows.email icon

    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

    Platforms

    • Online
    • iPhone
    • iPad
    • Android
    • Android Tablet
    Swisscows.email screenshot 1
     
  13. systemli.org icon

    systemli.org

     5 likes

    Systemli.org is a left network and technics-collective that was founded in 2003. Our aim is to provide safe and trustworthy communication services. The project addresses political activists and people who have a particular need to protect their data.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Online
     
  14. ProtonMail Extension icon

    ProtonMail Extension

     3 likes

    Unofficial ProtonMail extension. Provides notifications and makes it possible to close the ProtonMail tab, and even the browser, without getting logged out.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Online
    • ProtonMail
    • Google Chrome
    • Firefox
    ProtonMail Extension screenshot 1
     
  15. Galae icon

    Galae

     1 like

    Galae is a secure email service focused on deliverability, self-management and interoperability. It totally relies on free/libre opensource software.

    Cost / License

    Application type

    Platforms

    • Online
    • Software as a Service (SaaS)
     
12 of 23 Proton Mail alternatives