head to head · open source
Cal.com vs Rythe-Engine
Cal.com has 48,529 GitHub stars, 15,154 forks, 1,432 open issues and last shipped 4 days ago. Rythe-Engine has 534 stars, 30 forks, 10 open issues and last shipped 5 days ago. Cal.com leads on adoption by 8,988% (48,529 vs 534 stars). Cal.com is written in TypeScript under MIT; Rythe-Engine is written in C++ under MIT. Cal.com has attracted 31% as many forks as stars, Rythe-Engine 6%. Cal.com 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 | Rythe-Engine | |
|---|---|---|
| GitHub stars | ★ 49K | ★ 534 |
| License | MIT | MIT |
| Written in | TypeScript | C++ |
| Last push | 2026-09-14 | 2026-09-13 |
| Forks | ⑂ 15K | ⑂ 30 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Cal.com if
- You weight community size — 49K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick Rythe-Engine if
- You want the Rythe-Engine feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches C++
- You evaluated both and Rythe-Engine fits your workflow better
About Cal.com
Cal.diy is a fully open source, community maintained fork of Cal.com, stripped of all enterprise and commercial features. It provides a self hosted scheduling platform built on the T3 stack (Next.js, tRPC, Prisma, Tailwind CSS, Zod), licensed under MIT with no proprietary code or license keys required.
read the full Cal.com overview →
About Rythe-Engine
Rythe Engine is an MIT licensed, data oriented C++20 game engine built to make optimal use of modern hardware, aimed at C++ engine and gameplay programmers who want an async compute core and an ECS without assembling those pieces themselves.
read the full Rythe-Engine overview →
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Frequently asked questions
Is Cal.com or Rythe-Engine more popular?
Cal.com has 48,529 GitHub stars and Rythe-Engine has 534. Cal.com has the larger community by that measure.
Are Cal.com and Rythe-Engine free?
Both are open source. Cal.com is licensed under MIT and Rythe-Engine under MIT. Neither carries a licence fee.
What is the difference between Cal.com and Rythe-Engine?
Cal.com is written in TypeScript and Rythe-Engine in C++. 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 Rythe-Engine?
Choose Cal.com if you want the larger community (48,529 stars) or its MIT licence terms. Choose Rythe-Engine if its feature set, stack or MIT licence fits better. Both are self-hostable.