head to head · open source
ComfyUI vs Kai
ComfyUI has 133,963 GitHub stars, 15,874 forks, 4,894 open issues and last shipped today. Kai has 1,255 stars, 185 forks, 127 open issues and last shipped 2 days ago. ComfyUI leads on adoption by 10,574% (133,963 vs 1,255 stars). ComfyUI is written in Python under GPL-3.0; Kai is written in Kotlin under Apache-2.0. ComfyUI has attracted 12% as many forks as stars, Kai 15%. ComfyUI 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 | Kai | |
|---|---|---|
| GitHub stars | ★ 134K | ★ 1.3K |
| License | GPL-3.0 | Apache-2.0 |
| Written in | Python | Kotlin |
| Last push | 2026-09-20 | 2026-09-18 |
| Forks | ⑂ 16K | ⑂ 185 |
| 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 Kai if
- You want the Kai feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Kotlin
- You evaluated both and Kai 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 Kai
Kai 9000 is an Apache 2.0 licensed, open source AI assistant written in Kotlin that runs with persistent memory across Android, iOS, Windows, macOS, Linux, and the web, built for people who want a personal assistant that keeps its context and works on their own devices.
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Frequently asked questions
Is ComfyUI or Kai more popular?
ComfyUI has 133,963 GitHub stars and Kai has 1,255. ComfyUI has the larger community by that measure.
Are ComfyUI and Kai free?
Both are open source. ComfyUI is licensed under GPL-3.0 and Kai under Apache-2.0. Neither carries a licence fee.
What is the difference between ComfyUI and Kai?
ComfyUI is written in Python and Kai in Kotlin. 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 Kai?
Choose ComfyUI if you want the larger community (133,963 stars) or its GPL-3.0 licence terms. Choose Kai if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.