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Jace AI alternatives · Email

Open-source alternatives to Jace AI

Jace AI is not described as open source on its own site. 39 of the 125 other email apps in this directory are open source, according to their own sites.

Jace AI is a paid product with a free trial, starting at $20 per month, billed yearly ($25 billed monthly). 33 of them are free or have a free plan.

39 tools · Listings checked up to Nov 13, 2026 · Where the facts come from

The 12 closest to Jace AI

  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). Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Only Inbox Zero lists macOS, Windows, iOS and Android apps.
    • Only Inbox Zero lists a browser extension.
    • Inbox Zero is open source and self-hostable, according to its own site.
    Inbox Zero vs Jace AIInbox Zero pricing and details

  2. Zero Mail

    Open-source AI email client that connects your existing inboxes

    • Zero Mail starts at $20 per month (billing basis not shown). Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Zero Mail has a free plan. Jace AI does not, though it has a free trial.
    • Zero Mail is open source and self-hostable, according to its own site.
    • Jace AI also covers chat assistant, workflow automation and AI agents.
    Zero Mail pricing and details

  3. Wino Mail

    Free, open source mail and calendar app for Windows

    • Wino Mail has a free plan. Jace AI does not, though it has a free trial.
    • Only Wino Mail lists a Windows app.
    • Only Jace AI lists a web app.
    • Wino Mail is open source, according to its own site.
    Wino Mail pricing and details

  4. Claws Mail

    Lightweight GTK email and news client, free under the GPL

    • Claws Mail is free. Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Claws Mail has a free plan. Jace AI does not, though it has a free trial.
    • Only Claws Mail lists Linux and Windows apps.
    • Only Jace AI lists a web app.
    Claws Mail pricing and details

  5. Sylpheed

    Lightweight desktop email client built on GTK+

    • Sylpheed is free. Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Sylpheed has a free plan. Jace AI does not, though it has a free trial.
    • Only Sylpheed lists Windows, macOS and Linux apps.
    • Only Jace AI lists a web app.
    Sylpheed pricing and details

  6. Open-Xchange

    OX App Suite email platform sold to providers and governments

    • Open-Xchange is open source and self-hostable, according to its own site.
    • Open-Xchange also covers calendar.
    • Jace AI also covers chat assistant, inbox filtering, workflow automation and AI agents.
    Open-Xchange pricing and details

  7. Cypht

    Open-source webmail that combines many accounts in one inbox

    • Cypht is free. Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Cypht has a free plan. Jace AI does not, though it has a free trial.
    • Cypht is open source and self-hostable, according to its own site.
    • Jace AI also covers chat assistant, workflow automation and AI agents.
    Cypht pricing and details

  8. 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. Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Proton Mail has a free plan. Jace AI does not, though it has a free trial.
    • Only Proton Mail lists macOS, Windows, Linux, iOS and Android apps.
    • Proton Mail is open source and end-to-end encrypted, according to its own site.
    Proton Mail pricing and details

  9. Thunderbird

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

    • Thunderbird is free. Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Thunderbird has a free plan. Jace AI does not, though it has a free trial.
    • Only Thunderbird lists Windows, macOS, Linux and Android apps.
    • Only Jace AI lists a web app.
    Thunderbird pricing and details

  10. Tuta Mail

    End-to-end encrypted email and calendar from Germany

    • Tuta Mail starts at €3 per month, paid yearly (lowest paid personal plan). Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Tuta Mail has a free plan. Jace AI does not, though it has a free trial.
    • Only Tuta Mail lists Windows, macOS, Linux, iOS and Android apps.
    • Tuta Mail is open source and end-to-end encrypted, according to its own site.
    Tuta Mail pricing and details

  11. Mailspring

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

    • Mailspring starts at $8 per month, or $85 per year (Mailspring Pro). Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Mailspring has a free plan. Jace AI does not, though it has a free trial.
    • Only Mailspring lists macOS, Windows and Linux apps.
    • Only Jace AI lists a web app.
    Mailspring pricing and details

  12. Posteo

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

    • Posteo starts at €1 per month, prepaid (minimum top-up €12). Jace AI starts at $20 per month, billed yearly ($25 billed monthly).
    • Posteo is open source and end-to-end encrypted, according to its own site.
    • Posteo also covers notes and calendar.
    • Jace AI also covers chat assistant, inbox filtering, workflow automation and AI agents.
    Posteo pricing and details

27 more that are open source

All 39 in one table

Common questions

Is there an open-source alternative to Jace AI?

Yes. Inbox Zero, Zero Mail, Wino Mail, Claws Mail, Sylpheed, Open-Xchange, Cypht, Proton Mail and 31 more are open source, according to their own sites.

Is Jace AI open source?

Jace AI is not described as open source on its own site. The listing was checked on Oct 9, 2026 against the pages it cites.

Which of these email apps are free?

Zero Mail, Wino Mail, Claws Mail, Sylpheed, Cypht, Proton Mail, Thunderbird, Tuta Mail and 25 more 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 Nov 13, 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 Jace AI: the alternatives its listing names first, then the tools that share the most features with it.