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Missive alternatives · Email

Open-source alternatives to Missive

Missive 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.

Missive is a paid product with a free trial, starting at $14 per user / month, billed yearly ($18 billed monthly). 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 Missive

  1. Inbox Zero

    Open source AI email assistant for Gmail and Outlook

    • Inbox Zero starts at $18 per user / month, billed annually ($20 billed monthly). Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Only Inbox Zero lists a browser extension.
    • Inbox Zero is open source and self-hostable, according to its own site.
    • Inbox Zero also covers chat assistant and inbox filtering.
    Inbox Zero pricing and details

  2. Wino Mail

    Free, open source mail and calendar app for Windows

    • Wino Mail has a free plan. Missive does not, though it has a free trial.
    • Only Missive lists a web app.
    • Only Missive lists macOS, iOS and Android apps.
    • Wino Mail is open source, according to its own site.
    Wino Mail pricing and details

  3. Thunderbird

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

    • Thunderbird is free. Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Thunderbird has a free plan. Missive does not, though it has a free trial.
    • Only Thunderbird lists a Linux app.
    • Only Missive lists a web app.
    Thunderbird pricing and details

  4. 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. Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Proton Mail has a free plan. Missive does not, though it has a free trial.
    • Only Proton Mail lists a Linux app.
    • Proton Mail is open source and end-to-end encrypted, according to its own site.
    Proton 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). Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Tuta Mail has a free plan. Missive does not, though it has a free trial.
    • Only Tuta Mail lists a Linux app.
    • Tuta Mail is open source and end-to-end encrypted, according to its own site.
    Tuta Mail pricing and details

  6. Mailspring

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

    • Mailspring starts at $8 per month, or $85 per year (Mailspring Pro). Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Mailspring has a free plan. Missive does not, though it has a free trial.
    • Only Mailspring lists a Linux app.
    • Only Missive lists a web app.
    Mailspring pricing and details

  7. Posteo

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

    • Posteo starts at €1 per month, prepaid (minimum top-up €12). Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • Only Missive lists macOS, Windows, iOS and Android apps.
    • Posteo is open source and end-to-end encrypted, according to its own site.
    • Posteo also covers notes and calendar.
    Posteo pricing and details

  8. FairEmail

    Open source, privacy-oriented email client for Android

    • FairEmail starts at $7.49 one-time (pro features, US Google Play in-app purchase). Missive starts at $14 per user / month, billed yearly ($18 billed monthly).
    • FairEmail has a free plan. Missive does not, though it has a free trial.
    • Only Missive lists a web app.
    • Only Missive lists macOS, Windows and iOS apps.
    FairEmail pricing and details

Common questions

Is there an open-source alternative to Missive?

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

Is Missive open source?

Missive is not described as open source on its own site. The listing was checked on Oct 4, 2026 against the pages it cites.

Which of these email apps are free?

Wino Mail, Thunderbird, Proton Mail, Tuta Mail, Mailspring and FairEmail 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 Missive: the alternatives its listing names first, then the tools that share the most features with it.