head to head · open source
effect vs ratel
effect has 17,571 GitHub stars, 910 forks, 253 open issues and last shipped today. ratel has 563 stars, 32 forks, 23 open issues and last shipped 2 days ago. effect leads on adoption by 3,021% (17,571 vs 563 stars). effect is written in TypeScript under MIT; ratel is written in TypeScript under MIT. effect has attracted 5% as many forks as stars, ratel 6%. effect was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (observability, opentelemetry), so they are genuine substitutes rather than adjacent tools.
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
| effect | ratel | |
|---|---|---|
| GitHub stars | ★ 18K | ★ 563 |
| License | MIT | MIT |
| Written in | TypeScript | TypeScript |
| Last push | 2026-11-15 | 2026-11-13 |
| Forks | ⑂ 910 | ⑂ 32 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick effect if
- You weight community size — 18K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick ratel if
- You want the ratel feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and ratel fits your workflow better
About effect
Effect Effect is a library for building robust, maintainable, type safe, and production grade applications in TypeScript. It helps you handle the hard problems at scale: typed errors, dependency injection, structured concurrency, scheduling, tracing, and unified schema validation. Effect V4 is currently a release candidate. The main branch contains v4 development. Install V4 RC Requirements TypeScript 5.9 or newer. TypeScript 7 is recommended for the best performance and compatibility with Effect's TypeScript tooling. Node.js 18 or newer is the general minimum for running Effect on Node.js. Some integration…
read the full effect overview →
About ratel
Ratel See what your AI agent gets wrong, and what to change. On your own infrastructure. Docs • Skills • Discord Introduction Ratel is a self hosted platform for AI agents. Your agent sends it traces and its catalog of tools and skills. Ratel reads that traffic and shows you what the agent gets wrong, what people ask it for, and which changes would make it find and finish more. It is for anyone building or running an agent who wants to see how it behaves and keep that data on their own machines. It runs as one application and one Postgres database, and it needs nothing else: Console: the pages you read and act…
read the full ratel overview →
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Frequently asked questions
Is effect or ratel more popular?
effect has 17,571 GitHub stars and ratel has 563. effect has the larger community by that measure.
Are effect and ratel free?
Both are open source. effect is licensed under MIT and ratel under MIT. Neither carries a licence fee.
What is the difference between effect and ratel?
effect is written in TypeScript and ratel in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, effect or ratel?
Choose effect if you want the larger community (17,571 stars) or its MIT licence terms. Choose ratel if its feature set, stack or MIT licence fits better. Both are self-hostable.