head to head · open source
PageIndex vs LangWatch
PageIndex has 39,973 GitHub stars, 3,442 forks, 103 open issues and last shipped 2 days ago. LangWatch has 5,011 stars, 425 forks, 939 open issues and last shipped yesterday. PageIndex leads on adoption by 698% (39,973 vs 5,011 stars). PageIndex is written in Python under MIT; LangWatch is written in TypeScript under Apache-2.0. PageIndex has attracted 9% 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 (ai, 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
| PageIndex | LangWatch | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 5.0K |
| License | MIT | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-11-03 | 2026-11-04 |
| Forks | ⑂ 3.4K | ⑂ 425 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick PageIndex if
- You weight community size — 40K stars and counting
- You want the MIT 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 PageIndex
PageIndex: Vectorless, Reasoning based RAG Reasoning based RAG ◦ No Vector DB, No Chunking ◦ Context Aware Retrieval ◦ Reads Like a Human 🌐 Website • ☁️ Cloud • 📖 Docs • 📝 Blog • ✉️ Contact Updates [Aug '26] 🔥 PageIndex SDK : pip install U pageindex now ships local mode : index, retrieve, and chat entirely on your machine with your own LLM key, or point the same client at PageIndex Cloud with an API key. [Aug '26] ⚡ PageIndex Flash : fast tree index generation for text based PDFs, now the default indexing method in PageIndex SDK local mode. Scale PageIndex to Millions of Documents: PageIndex File System is a…
read the full PageIndex overview →
About LangWatch
Website · Docs · Discord · Self hosting Why LangWatch? The platform for LLM evaluations and AI agent testing. We help teams test, simulate, evaluate, and monitor LLM powered agents end to end — before release and in production. Built for teams that need regression testing, simulations, and production observability without building custom tooling. End to end agent simulations Run realistic scenarios against your full stack (tools, state, user simulator, judge) and pinpoint where your agents break, and why? down to each decision. Eval + observability + prompts in one loop Trace → dataset → evaluate → optimize…
read the full LangWatch overview →
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Frequently asked questions
Is PageIndex or LangWatch more popular?
PageIndex has 39,973 GitHub stars and LangWatch has 5,011. PageIndex has the larger community by that measure.
Are PageIndex and LangWatch free?
Both are open source. PageIndex is licensed under MIT and LangWatch under Apache-2.0. Neither carries a licence fee.
What is the difference between PageIndex and LangWatch?
PageIndex 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, PageIndex or LangWatch?
Choose PageIndex if you want the larger community (39,973 stars) or its MIT licence terms. Choose LangWatch if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.