head to head · open source
ComfyUI vs sim
ComfyUI has 133,963 GitHub stars, 15,874 forks, 4,894 open issues and last shipped today. sim has 29,680 stars, 3,843 forks, 336 open issues and last shipped today. ComfyUI leads on adoption by 351% (133,963 vs 29,680 stars). ComfyUI is written in Python under GPL-3.0; sim is written in TypeScript under Apache-2.0. ComfyUI has attracted 12% 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 (ai), 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
| ComfyUI | sim | |
|---|---|---|
| GitHub stars | ★ 134K | ★ 30K |
| License | GPL-3.0 | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-09-20 | 2026-09-20 |
| Forks | ⑂ 16K | ⑂ 3.8K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick ComfyUI if
- You weight community size — 134K stars and counting
- You want the GPL-3.0 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 ComfyUI
ComfyUI is a GPL 3.0 licensed Python and PyTorch node graph application, local API, and backend for running diffusion models across image, video, audio, 3D, and text workflows, built for visual professionals who want control over every model, parameter, and output, and for developers who embed those workflows into production pipelines.
read the full ComfyUI 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 ComfyUI or sim more popular?
ComfyUI has 133,963 GitHub stars and sim has 29,680. ComfyUI has the larger community by that measure.
Are ComfyUI and sim free?
Both are open source. ComfyUI is licensed under GPL-3.0 and sim under Apache-2.0. Neither carries a licence fee.
What is the difference between ComfyUI and sim?
ComfyUI 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, ComfyUI or sim?
Choose ComfyUI if you want the larger community (133,963 stars) or its GPL-3.0 licence terms. Choose sim if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.