Open Source Proton Mail Alternatives for Mozilla Firefox

Proton Mail is not available for Mozilla Firefox but there are a few alternatives with similar functionality. The best open source Mozilla Firefox alternative is FlowCrypt. If that doesn't suit you, our users have ranked more than 50 alternatives to Proton Mail and three of them are open source and available for Mozilla Firefox so hopefully you can find a suitable replacement. Other interesting open source Mozilla Firefox alternatives to Proton Mail are ProtonMail Extension and WebPG.

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Alternatives list

  1. FlowCrypt icon

    FlowCrypt

     17 likes
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    FlowCrypt (formerly CryptUp) is the easiest PGP encryption for Gmail. It behaves just like standard email, except it's encrypted.

    Cost / License

    • Freemium (Pay once)
    • Open Source

    Platforms

    • Android
    • iPhone
    • Google Chrome
    • Brave
    • Firefox
    • OpenPGP
    FlowCrypt screenshot 1
     
  2. ProtonMail Extension icon

    ProtonMail Extension

     3 likes
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    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
     
  4. WebPG icon

    WebPG

     2 likes
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    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

    Alerts

    • Discontinued

    Platforms

    • Mac
    • Windows
    • Linux
    • Google Chrome
    • Thunderbird
    • SeaMonkey
    • Chromium
    • Firefox
    • OpenPGP
    WebPG screenshot 1
     
3 of 3 Proton Mail alternatives