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Gmail alternatives · Email

Open-source alternatives to Gmail

Gmail is not described as open source on its own site. 8 of the 51 other email apps in this directory are open source, according to their own sites.

Gmail has a free plan. Paid plans start at $7 per user / month with a 1-year commitment (Workspace Business Starter). 6 of them are free or have a free plan.

8 tools · Listings checked up to Oct 9, 2026 · Where the facts come from

How each one differs from Gmail

  1. Proton Mail

    End-to-end encrypted email service based in Switzerland

    • Proton Mail starts at $3.99 per month, billed every 12 months ($47.88); $4.99 billed monthly. Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Proton Mail lists macOS, Windows and Linux apps.
    • Proton Mail is open source and end-to-end encrypted, according to its own site.
    • Proton Mail also covers calendar.
    Proton Mail vs GmailProton Mail pricing and details

  2. FairEmail

    Open source, privacy-oriented email client for Android

    • FairEmail starts at $7.49 one-time (pro features, US Google Play in-app purchase). Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Gmail lists a web app.
    • Only Gmail lists an iOS app.
    • FairEmail is open source and end-to-end encrypted, according to its own site.
    FairEmail vs GmailFairEmail pricing and details

  3. Inbox Zero

    Open source AI email assistant for Gmail and Outlook

    • Inbox Zero starts at $18 per user / month, billed annually ($20 billed monthly). Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Gmail has a free plan. Inbox Zero does not, though it has a free trial.
    • Only Inbox Zero lists macOS and Windows apps.
    • Only Inbox Zero lists a browser extension.
    Inbox Zero pricing and details

  4. Wino Mail

    Free, open source mail and calendar app for Windows

    • Only Wino Mail lists a Windows app.
    • Only Gmail lists a web app.
    • Only Gmail lists iOS and Android apps.
    • Wino Mail is open source, according to its own site.
    Wino Mail pricing and details

  5. Tuta Mail

    End-to-end encrypted email and calendar from Germany

    • Tuta Mail starts at €3 per month, paid yearly (lowest paid personal plan). Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Tuta Mail lists Windows, macOS and Linux apps.
    • Tuta Mail is open source and end-to-end encrypted, according to its own site.
    • Tuta Mail also covers calendar.
    Tuta Mail pricing and details

  6. Thunderbird

    Free, open-source email app for Windows, macOS, Linux and Android

    • Thunderbird is free. Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Thunderbird lists Windows, macOS and Linux apps.
    • Only Gmail lists a web app.
    • Only Gmail lists an iOS app.
    Thunderbird pricing and details

  7. Mailspring

    Open-source desktop email client for Mac, Windows and Linux

    • Mailspring starts at $8 per month, or $85 per year (Mailspring Pro). Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Mailspring lists macOS, Windows and Linux apps.
    • Only Gmail lists a web app.
    • Only Gmail lists iOS and Android apps.
    Mailspring pricing and details

  8. Posteo

    Ad-free, green-powered email from Berlin for €1 a month

    • Posteo starts at €1 per month, prepaid (minimum top-up €12). Gmail starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Gmail has a free plan. Posteo does not.
    • Only Gmail lists iOS and Android apps.
    • Posteo is open source and end-to-end encrypted, according to its own site.
    Posteo pricing and details

Common questions

Is there an open-source alternative to Gmail?

Yes. Proton Mail, FairEmail, Inbox Zero, Wino Mail, Tuta Mail, Thunderbird, Mailspring and Posteo are open source, according to their own sites.

Is Gmail open source?

Gmail is not described as open source on its own site. The listing was checked on Oct 5, 2026 against the pages it cites.

Which of these email apps are free?

Proton Mail, FairEmail, Wino Mail, Tuta Mail, Thunderbird and Mailspring are free or have a free plan.

When was this checked?

Each listing shows its own date. On this page they run from Oct 4, 2026 to Oct 9, 2026. Vendors change prices and plans without notice, so confirm on their site before you buy.

This page is built from the listings. A tool is here because its listing says so, and the order is how close each is to Gmail: the alternatives its listing names first, then the tools that share the most features with it.