head to head · open source
effect vs tapir
effect has 17,476 GitHub stars, 895 forks, 253 open issues and last shipped yesterday. tapir has 1,476 stars, 473 forks, 173 open issues and last shipped 3 days ago. effect leads on adoption by 1,084% (17,476 vs 1,476 stars). effect is written in TypeScript under MIT; tapir is written in Scala under Apache-2.0. effect has attracted 5% as many forks as stars, tapir 32%. effect was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (observability), 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 | tapir | |
|---|---|---|
| GitHub stars | ★ 17K | ★ 1.5K |
| License | MIT | Apache-2.0 |
| Written in | TypeScript | Scala |
| Last push | 2026-11-04 | 2026-11-02 |
| Forks | ⑂ 895 | ⑂ 473 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick effect if
- You weight community size — 17K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick tapir if
- You want the tapir feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Scala
- You evaluated both and tapir 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 tapir
Welcome! Intro Tapir is a library to describe HTTP APIs, expose them as a server, consume as a client, and automatically document using open standards. Tapir is fast and developer friendly. The endpoint definition APIs are crafted with readability and discoverability in mind. Our Netty based server is one of the best performing Scala HTTP servers available. Tapir integrates with all major Scala stacks, so you can use your favorite approach to Functional Programming, while leveraging all the benefits that Tapir brings! Seamless integration with the Scala and HTTP ecosystems is one of Tapir's major strengths: all…
read the full tapir overview →
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Frequently asked questions
Is effect or tapir more popular?
effect has 17,476 GitHub stars and tapir has 1,476. effect has the larger community by that measure.
Are effect and tapir free?
Both are open source. effect is licensed under MIT and tapir under Apache-2.0. Neither carries a licence fee.
What is the difference between effect and tapir?
effect is written in TypeScript and tapir in Scala. 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 tapir?
Choose effect if you want the larger community (17,476 stars) or its MIT licence terms. Choose tapir if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.