head to head · open source
Jan vs sim
Jan has 44,566 GitHub stars, 3,040 forks, 521 open issues and last shipped yesterday. sim has 29,680 stars, 3,843 forks, 336 open issues and last shipped today. Jan leads on adoption by 50% (44,566 vs 29,680 stars). Jan is written in TypeScript under a custom or non-standard licence; sim is written in TypeScript under Apache-2.0. Jan has attracted 7% 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.
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
| Jan | sim | |
|---|---|---|
| GitHub stars | ★ 45K | ★ 30K |
| License | Custom / other | Apache-2.0 |
| Written in | TypeScript | TypeScript |
| Last push | 2026-09-19 | 2026-09-20 |
| Forks | ⑂ 3.0K | ⑂ 3.8K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Jan if
- You weight community size — 45K stars and counting
- You want the Custom / other license terms
- Your stack matches TypeScript
- 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 Jan
Jan is an open source desktop application that serves as a ChatGPT replacement, enabling users to run large language models (LLMs) locally on their machines or connect to cloud based providers like OpenAI and Anthropic. It is built with Tauri, TypeScript, and integrates llama.cpp for efficient local inference, targeting privacy conscious users who want full control over their AI workflows without sending data to third parties.
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 Jan or sim more popular?
Jan has 44,566 GitHub stars and sim has 29,680. Jan has the larger community by that measure.
Are Jan and sim free?
Both are open source. Jan has no licence declared in this registry, and sim is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Jan and sim?
Jan is written in TypeScript 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, Jan or sim?
Choose Jan if you want the larger community (44,566 stars) or its Custom / other licence terms. Choose sim if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.