How it works
Most image tools give you a prompt box and a button. ComfyUI shows you the machinery. Each node does one job, such as load a model, encode the prompt, sample the image or save the file, and you connect the nodes with wires. The finished graph is called a workflow. It is a precise record of how an image was made, and it can be saved, shared and run again.
That design is why ComfyUI is popular with people who need repeatable results. You can add steps that a simple interface hides: a second pass to add detail, an upscaler, a face fix, a LoRA, a pose guide. New models tend to be supported quickly, and the project now covers video, audio and other model types as well as images. Community-made custom nodes extend it further.
Creators meet ComfyUI when they build a consistent AI character or a repeatable content pipeline. The cost is a learning curve and hardware. It runs on your own computer with a suitable graphics card, on a rented cloud GPU or through a hosted service. Take care with downloaded workflows and custom nodes, because they run code on your machine. Install them only from sources you trust.
A worked example
A creator wants every character image made the same way, so that the results stay consistent.
- Load a base model and the character's LoRA with two loader nodes.
- Connect a prompt node, a sampler node and a save node, then generate a first image.
- Add an upscale node and a face detail pass after the sampler, and compare the result.
- Save the workflow file. Next week the same graph with a new prompt produces images in the same style.
An illustration, not a real account. Any numbers in it are made up to show the method, and are not benchmarks.
Common mistakes
- Thinking ComfyUI is a model. It is the program that runs models such as Stable Diffusion or FLUX.
- Installing custom nodes from unknown sources. They run code on your computer.
- Copying a complex workflow before understanding a basic one. Build the simple text-to-image graph first.
Questions people ask
Is ComfyUI free?
Yes. The software is open source under the GPL-3.0 license and free to run on your own hardware. You pay for the computer or cloud GPU, and hosted versions charge for use.
Is ComfyUI hard to learn?
It is harder than a prompt box. The basics are a handful of nodes, and the rest is learned one technique at a time.
Should I use ComfyUI or AUTOMATIC1111?
Both run Stable Diffusion models. AUTOMATIC1111 is a form-style interface. ComfyUI uses a node graph, which is more flexible and easier to repeat exactly.
Sources
The repository describes ComfyUI as a modular diffusion model GUI, API and backend with a graph and nodes interface, and shows a GPL-3.0 license.
Comfy Org: ComfyUI on GitHub read 13 October 2026
The official documentation calls ComfyUI a node-based interface and inference engine for generative AI, and says it is completely open source and can run on your local device.
Every link was opened on 13 October 2026. Products and policies change, so check the source before you rely on a figure.