head to head · open source
Cal.com vs appointment
Cal.com has 49,651 GitHub stars, 15,521 forks, 1,432 open issues and last shipped yesterday. appointment has 556 stars, 28 forks, 186 open issues and last shipped yesterday. Cal.com leads on adoption by 8,830% (49,651 vs 556 stars). Cal.com is written in TypeScript under MIT; appointment is written in Python under MPL-2.0. Cal.com has attracted 31% as many forks as stars, appointment 5%. appointment was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Cal.com | appointment | |
|---|---|---|
| GitHub stars | ★ 50K | ★ 556 |
| License | MIT | MPL-2.0 |
| Written in | TypeScript | Python |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 16K | ⑂ 28 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Cal.com if
- You weight community size — 50K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick appointment if
- You want the appointment feature set and don't need the biggest community
- You prefer the MPL-2.0 license terms
- Your stack matches Python
- You evaluated both and appointment fits your workflow better
About Cal.com
[!WARNING] Use at your own risk. Cal.diy is the open source community edition of Cal.com and it is intended for users who want to self host their own Cal.diy instance. It is strictly recommended for personal, non production use. Please review all installation and configuration steps carefully. Self hosting requires advanced knowledge of server administration, database management, and securing sensitive data. Proceed only if you are comfortable with these responsibilities. [!TIP] For any commercial and enterprise ready scheduling infrastructure, use Cal.com, not Cal.diy; hosted by us or get invited to on prem…
read the full Cal.com overview →
About appointment
Thunderbird Appointment Invite others to grab times on your calendar. Choose a date. Make appointments as easy as it gets. Screenshots The bookers page for attendees and the dashboard for subscribers: Availability setup, managing bookings and general settings: Feedback and Support If you'd like to give feedback or need support, please see our Topicbox. Get started Using Docker is the recommended and for now the only supported method of building and developing Thunderbird Appointment. A detailed technical documentation of the application architecture can be found in the docs folder (still work in progress)…
read the full appointment overview →
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Frequently asked questions
Is Cal.com or appointment more popular?
Cal.com has 49,651 GitHub stars and appointment has 556. Cal.com has the larger community by that measure.
Are Cal.com and appointment free?
Both are open source. Cal.com is licensed under MIT and appointment under MPL-2.0. Neither carries a licence fee.
What is the difference between Cal.com and appointment?
Cal.com is written in TypeScript and appointment in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Cal.com or appointment?
Choose Cal.com if you want the larger community (49,651 stars) or its MIT licence terms. Choose appointment if its feature set, stack or MPL-2.0 licence fits better. Both are self-hostable.