head to head · open source
llama_index vs Spanlens
llama_index has 52,202 GitHub stars, 8,162 forks, 770 open issues and last shipped yesterday. Spanlens has 13 stars, 0 forks, 1 open issues and last shipped 4 days ago. llama_index leads on adoption by 401,454% (52,202 vs 13 stars). llama_index is written in Python under MIT; Spanlens is written in TypeScript under MIT. llama_index has attracted 16% as many forks as stars, Spanlens 0%. llama_index was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (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
| llama_index | Spanlens | |
|---|---|---|
| GitHub stars | ★ 52K | ★ 13 |
| License | MIT | MIT |
| Written in | Python | TypeScript |
| Last push | 2026-09-17 | 2026-09-14 |
| Forks | ⑂ 8.2K | ⑂ 0 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick llama_index if
- You weight community size — 52K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick Spanlens if
- You want the Spanlens feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and Spanlens fits your workflow better
About llama_index
LlamaIndex is an MIT licensed, open source Python framework for building agentic applications — retrieval augmented generation systems, agents and multi agent workflows — on top of private documents and data, and it is aimed at AI engineers and teams who need to connect large language models to their own sources of context.
read the full llama_index overview →
About Spanlens
Spanlens is an MIT licensed, open source LLM observability and monitoring layer that sits as a drop in proxy in front of OpenAI, Anthropic, and Gemini clients to log every call's cost, tokens, latency, and agent traces, built for developers running LLM applications in production who need more than a provider dashboard's total spend.
read the full Spanlens overview →
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Frequently asked questions
Is llama_index or Spanlens more popular?
llama_index has 52,202 GitHub stars and Spanlens has 13. llama_index has the larger community by that measure.
Are llama_index and Spanlens free?
Both are open source. llama_index is licensed under MIT and Spanlens under MIT. Neither carries a licence fee.
What is the difference between llama_index and Spanlens?
llama_index is written in Python and Spanlens 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, llama_index or Spanlens?
Choose llama_index if you want the larger community (52,202 stars) or its MIT licence terms. Choose Spanlens if its feature set, stack or MIT licence fits better. Both are self-hostable.