head to head · open source
effect vs langsmith-sdk
effect has 16,138 GitHub stars, 752 forks, 253 open issues and last shipped today. langsmith-sdk has 1,060 stars, 298 forks, 216 open issues and last shipped yesterday. effect leads on adoption by 1,422% (16,138 vs 1,060 stars). effect is written in TypeScript under MIT; langsmith-sdk is written in Python under MIT. effect has attracted 5% as many forks as stars, langsmith-sdk 28%. 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 | langsmith-sdk | |
|---|---|---|
| GitHub stars | ★ 16K | ★ 1.1K |
| License | MIT | MIT |
| Written in | TypeScript | Python |
| Last push | 2026-09-20 | 2026-09-19 |
| Forks | ⑂ 752 | ⑂ 298 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick effect if
- You weight community size — 16K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick langsmith-sdk if
- You want the langsmith-sdk feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and langsmith-sdk fits your workflow better
About effect
Effect is a TypeScript library for building robust, maintainable, type safe, and production grade applications. It lives in the TypeScript and JavaScript ecosystem, distributed as the core effect package alongside a monorepo of integration packages that extend it. The project is MIT licensed, has been developed for roughly seven years, and currently ships Effect V4 as a release candidate, with the main branch holding v4 development and the v3 branch retaining the previous line.
read the full effect overview →
About langsmith-sdk
LangSmith SDK is the official pair of Python and JavaScript client libraries for the LangSmith platform, built and maintained by LangChain for teams that need to debug, evaluate, and monitor language models and intelligent agents.
read the full langsmith-sdk overview →
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Frequently asked questions
Is effect or langsmith-sdk more popular?
effect has 16,138 GitHub stars and langsmith-sdk has 1,060. effect has the larger community by that measure.
Are effect and langsmith-sdk free?
Both are open source. effect is licensed under MIT and langsmith-sdk under MIT. Neither carries a licence fee.
What is the difference between effect and langsmith-sdk?
effect is written in TypeScript and langsmith-sdk 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, effect or langsmith-sdk?
Choose effect if you want the larger community (16,138 stars) or its MIT licence terms. Choose langsmith-sdk if its feature set, stack or MIT licence fits better. Both are self-hostable.