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Hiver alternatives · Email

Open-source alternatives to Hiver

Hiver 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.

Hiver is a paid product with a free trial, starting at $25 per user / month, billed annually ($35 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 Hiver

  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). Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Only Inbox Zero lists macOS and Windows apps.
    • Inbox Zero is open source and self-hostable, according to its own site.
    • Inbox Zero also covers chat assistant, email client 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. Hiver does not, though it has a free trial.
    • Only Wino Mail lists a Windows app.
    • Only Hiver lists a web app.
    • Only Hiver lists iOS and Android apps.
    Wino Mail pricing and details

  3. 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. Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Proton Mail has a free plan. Hiver does not, though it has a free trial.
    • Only Proton Mail lists macOS, Windows and Linux apps.
    • Only Hiver lists a browser extension.
    Proton Mail pricing and details

  4. Thunderbird

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

    • Thunderbird is free. Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Thunderbird has a free plan. Hiver does not, though it has a free trial.
    • Only Thunderbird lists Windows, macOS and Linux apps.
    • Only Hiver lists a web app.
    Thunderbird 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). Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Tuta Mail has a free plan. Hiver does not, though it has a free trial.
    • Only Tuta Mail lists Windows, macOS and Linux apps.
    • Only Hiver lists a browser extension.
    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). Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Mailspring has a free plan. Hiver does not, though it has a free trial.
    • Only Mailspring lists macOS, Windows and Linux apps.
    • Only Hiver 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). Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • Only Hiver lists iOS and Android apps.
    • Only Hiver lists a browser extension.
    • Posteo is open source and end-to-end encrypted, according to its own site.
    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). Hiver starts at $25 per user / month, billed annually ($35 billed monthly).
    • FairEmail has a free plan. Hiver does not, though it has a free trial.
    • Only Hiver lists a web app.
    • Only Hiver lists an iOS app.
    FairEmail pricing and details

Common questions

Is there an open-source alternative to Hiver?

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

Is Hiver open source?

Hiver 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?

Wino Mail, Proton Mail, Thunderbird, 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 Hiver: the alternatives its listing names first, then the tools that share the most features with it.