head to head · open source
Langchain-Chatchat vs sim
Langchain-Chatchat has 38,643 GitHub stars, 6,266 forks, 26 open issues and last shipped 10 months ago. sim has 29,680 stars, 3,843 forks, 336 open issues and last shipped today. Langchain-Chatchat leads on adoption by 30% (38,643 vs 29,680 stars). Langchain-Chatchat is written in Python under Apache-2.0; sim is written in TypeScript under Apache-2.0. Langchain-Chatchat has attracted 16% as many forks as stars, sim 13%. sim was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (chatbot), 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
| Langchain-Chatchat | sim | |
|---|---|---|
| GitHub stars | ★ 39K | ★ 30K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2025-11-10 | 2026-09-20 |
| Forks | ⑂ 6.3K | ⑂ 3.8K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Langchain-Chatchat if
- You weight community size — 39K 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 sim if
- You want the sim 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 sim fits your workflow better
About Langchain-Chatchat
Langchain Chatchat (formerly Langchain ChatGLM) is an open source RAG and Agent application built on the Langchain framework and designed to run against local large language models such as ChatGLM, Qwen, and Llama. It lives in the Python ecosystem, is distributed under the Apache 2.0 license, and is published on PyPI as langchain chatchat . The project targets Chinese language scenarios and open source models specifically, with the stated goal of providing a knowledge base question answering solution that can run entirely offline.
read the full Langchain-Chatchat overview →
About sim
Sim is an open source collaborative workspace for building, deploying, and monitoring AI agents and workflows. It lives in the TypeScript ecosystem and is distributed under the Apache 2.0 license, with a repository that has accumulated roughly 29,600 stars and 3,800 forks over its two year history. The project positions itself as a single surface where chat, workflows, tables, files, and knowledge coexist, whether accessed through a browser or a desktop application for macOS.
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Frequently asked questions
Is Langchain-Chatchat or sim more popular?
Langchain-Chatchat has 38,643 GitHub stars and sim has 29,680. Langchain-Chatchat has the larger community by that measure.
Are Langchain-Chatchat and sim free?
Both are open source. Langchain-Chatchat is licensed under Apache-2.0 and sim under Apache-2.0. Neither carries a licence fee.
What is the difference between Langchain-Chatchat and sim?
Langchain-Chatchat is written in Python and sim 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, Langchain-Chatchat or sim?
Choose Langchain-Chatchat if you want the larger community (38,643 stars) or its Apache-2.0 licence terms. Choose sim if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.