head to head · open source
vllm vs LangWatch
vllm has 92,028 GitHub stars, 22,335 forks, 7,953 open issues and last shipped yesterday. LangWatch has 4,810 stars, 393 forks, 939 open issues and last shipped yesterday. vllm leads on adoption by 1,813% (92,028 vs 4,810 stars). vllm is written in Python under Apache-2.0; LangWatch is written in TypeScript under Apache-2.0. vllm has attracted 24% as many forks as stars, LangWatch 8%. LangWatch was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (gpt, llm), 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
| vllm | LangWatch | |
|---|---|---|
| GitHub stars | ★ 92K | ★ 4.8K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 22K | ⑂ 393 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick vllm if
- You weight community size — 92K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick LangWatch if
- You want the LangWatch feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches TypeScript
- You evaluated both and LangWatch fits your workflow better
About vllm
vLLM is a high throughput, memory efficient Python library for LLM inference and serving, built for ML engineers and platform teams who need to run open weight models on their own hardware at production scale.
About LangWatch
LangWatch is an open source TypeScript platform for LLM evaluations and AI agent testing, licensed under Apache 2.0. It lives in the machine learning infrastructure ecosystem for teams that build LLM powered agents and need to test, simulate, evaluate, and monitor agents before release and in production.
read the full LangWatch overview →
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Frequently asked questions
Is vllm or LangWatch more popular?
vllm has 92,028 GitHub stars and LangWatch has 4,810. vllm has the larger community by that measure.
Are vllm and LangWatch free?
Both are open source. vllm is licensed under Apache-2.0 and LangWatch under Apache-2.0. Neither carries a licence fee.
What is the difference between vllm and LangWatch?
vllm is written in Python and LangWatch 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, vllm or LangWatch?
Choose vllm if you want the larger community (92,028 stars) or its Apache-2.0 licence terms. Choose LangWatch if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.