head to head · open source
ComfyUI vs sim
ComfyUI has 144,907 GitHub stars, 17,244 forks, 4,894 open issues and last shipped yesterday. sim has 29,983 stars, 3,883 forks, 336 open issues and last shipped yesterday. ComfyUI leads on adoption by 383% (144,907 vs 29,983 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 | ★ 145K | ★ 30K |
| License | GPL-3.0 | Apache-2.0 |
| Written in | Python | TypeScript |
| Last push | 2026-11-04 | 2026-11-04 |
| Forks | ⑂ 17K | ⑂ 3.9K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick ComfyUI if
- You weight community size — 145K 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 The most powerful and modular AI engine for content creation. [![Website][website shield]][website url] [![Dynamic JSON Badge][discord shield]][discord url] [![Twitter][twitter shield]][twitter url] [![Matrix][matrix shield]][matrix url] [![][github release shield]][github release link] [![][github release date shield]][github release link] [![][github downloads shield]][github downloads link] [![][github downloads latest shield]][github downloads link] [matrix shield]: [matrix url]: [website shield]: [website url]: [discord shield]: [discord url]: [twitter shield]: [twitter url]: [github release…
read the full ComfyUI overview →
About sim
A workspace to build, deploy and manage AI agents and workflows. Quickstart Cloud hosted: sim.ai Self hosted Open Desktop: macOS macOS 12+, Apple Silicon and Intel. See the desktop docs to point it at a self hosted deployment. Capabilities Connect 1,000+ integrations and every major LLM Add Slack, Notion, HubSpot, Salesforce, databases, and more Build agents visually, conversationally, or with code Ingest files, knowledge bases, and structured table data Monitor runs, logs, schedules, and workflow activity One workspace, every surface Chat and workflows are just the start — tables, files, and knowledge all live…
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Frequently asked questions
Is ComfyUI or sim more popular?
ComfyUI has 144,907 GitHub stars and sim has 29,983. 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 (144,907 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.