ComfyUI is a free, open-source, node-based interface for building AI image and video generation workflows: you connect visual nodes on a canvas rather than typing a single prompt into a box.
Its node-graph approach exposes the full pipeline behind an AI generation (model, sampler, conditioning, upscaling steps, and more), which gives far more control and repeatability than a simple prompt box: at the cost of a real learning curve.
Technical users and power users who want fine-grained control over Stable Diffusion-style generation and are willing to learn a node-based workflow; not a fit if you just want a quick prompt-to-image result.
Always free and open source: self-host it yourself (GitHub, Docker) at no cost. An optional hosted Comfy Cloud service exists for people without a capable GPU, starting around $20/month.
