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OnceHub alternatives · Calendar

Open-source alternatives to OnceHub

OnceHub is not described as open source on its own site. 13 of the 114 other calendar and scheduling apps in this directory are open source, according to their own sites.

OnceHub has a free plan. Paid plans start at $10 per seat / month, billed annually ($12 billed monthly). 12 of them are free or have a free plan.

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

The 12 closest to OnceHub

  1. Easy!Appointments

    Open source appointment scheduler you host on your own server

    • Easy!Appointments starts at $20 per month, billed annually ($240 a year), for managed hosting. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only OnceHub lists a browser extension.
    • Easy!Appointments is open source and self-hostable, according to its own site.
    • Easy!Appointments also covers calendar and appointment booking.
    Easy!Appointments pricing and details

  2. Proton Calendar

    End-to-end encrypted calendar from the maker of Proton Mail

    • Proton Calendar starts at $3.99 per month, billed every 12 months ($47.88); $4.99 billed monthly. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Proton Calendar lists macOS, Windows, Linux, iOS and Android apps.
    • Only OnceHub lists a browser extension.
    • Proton Calendar is open source and end-to-end encrypted, according to its own site.
    Proton Calendar pricing and details

  3. Rallly

    Open-source meeting polls for finding a time that suits a group

    • Rallly starts at $6 per seat / month, billed yearly ($10 billed monthly). OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only OnceHub lists a browser extension.
    • Rallly is open source and self-hostable, according to its own site.
    • OnceHub also covers booking links and reports.
    Rallly pricing and details

  4. Tuta Calendar

    End-to-end encrypted calendar bundled with Tuta Mail

    • Tuta Calendar starts at €3 per month, paid yearly (€3.60 paid monthly). OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Tuta Calendar lists macOS, Windows, Linux, iOS and Android apps.
    • Only OnceHub lists a browser extension.
    • Tuta Calendar is open source and end-to-end encrypted, according to its own site.
    Tuta Calendar pricing and details

  5. Itsycal

    Free, tiny menu bar calendar for the Mac

    • Itsycal is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Itsycal lists a macOS app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    Itsycal pricing and details

  6. MeetingBar

    Free Mac menu bar app that shows and joins your next meeting

    • MeetingBar is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only MeetingBar lists a macOS app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    MeetingBar pricing and details

  7. Fossify Calendar

    Open-source Android calendar with no ads, tracking or account

    • Fossify Calendar is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Fossify Calendar lists an Android app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    Fossify Calendar pricing and details

  8. Etar

    Open-source Material Design calendar for Android

    • Etar is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Etar lists an Android app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    Etar pricing and details

  9. GNOME Calendar

    Free, open-source calendar app for the GNOME desktop on Linux

    • GNOME Calendar is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only GNOME Calendar lists a Linux app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    GNOME Calendar pricing and details

  10. Merkuro Calendar

    Open-source calendar and task app from KDE for Linux

    • Merkuro Calendar is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Merkuro Calendar lists a Linux app.
    • Only OnceHub lists a web app.
    • Only OnceHub lists a browser extension.
    Merkuro Calendar pricing and details

  11. Crab Fit

    Free, open-source availability heat map for group events

    • Crab Fit is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only Crab Fit lists an Android app.
    • Crab Fit is open source and self-hostable, according to its own site.
    • Crab Fit also covers surveys.
    Crab Fit pricing and details

  12. Timeful

    Free, open-source group availability poll with calendar autofill

    • Timeful is free. OnceHub starts at $10 per seat / month, billed annually ($12 billed monthly).
    • Only OnceHub lists a browser extension.
    • Timeful is open source and self-hostable, according to its own site.
    • Timeful also covers calendar and surveys.
    Timeful pricing and details

1 more that are open source

All 13 in one table

Common questions

Is there an open-source alternative to OnceHub?

Yes. Easy!Appointments, Proton Calendar, Rallly, Tuta Calendar, Itsycal, MeetingBar, Fossify Calendar, Etar and 5 more are open source, according to their own sites.

Is OnceHub open source?

OnceHub 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 calendar and scheduling apps are free?

Easy!Appointments, Proton Calendar, Rallly, Tuta Calendar, Itsycal, MeetingBar, Fossify Calendar, Etar and 4 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 5, 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 OnceHub: the alternatives its listing names first, then the tools that share the most features with it.