ComfyUI, a startup that helps creators control image, video, and audio outputs from diffusion models with a node-based workflow, has raised a $30 million funding round at a $500 million valuation.

The round was led by Craft Ventures, with participation from other investors including Pace Capital, Chemistry, and TruArrow.

ComfyUI was started as an open-source project in 2023, shortly after the introduction of diffusion models. At that time, models like Midjourney and OpenAI’s DALL-E were barely functional, frequently making major mistakes, such as adding extra fingers to hands.

To address these limitations, the project founders developed a modular framework that gives creators granular control over every step of the generation process.

Their tool gained such significant traction among creative professionals that it eventually evolved into a formal startup. In late 2024, ComfyUI raised $19 million in Series A financing from investors including Chemistry Ventures, Cursor Capital, and Guillermo Rauch, founder of Vercel.

Although the latest diffusion models have come a long way from adding a sixth digit to hands, the need for the granular precision that ComfyUI offers has only grown.

“If you think about your typical prompt-based solution, like Midjourney or ChatGPT, you ask for something, it [gets only] 60% – 80% there,” Yoland Yan, ComfyUI’s co-founder and CEO, told TechCrunch. “But to change that remaining 20%, you have to try this slot machine.”

Yan (pictured left) compared the process to playing in a casino because prompting the model to make a small change can result in a completely different output, including overwriting the parts that were already perfect.

ComfyUI’s node-based interface allows creators to link specific components of the generation process, giving them full control over the quality of their final output.

“You cannot easily convey that message in the prompt box [of a foundational model],” Yan said.

Creators seem to agree, as ComfyUI claims to have over 4 million users.

The tool is being used by creative professionals for visual effects, animation, advertising, and even industrial design.

The startup says its offering has become such a necessary tool of the trade for technical artists and other creatives that it is not uncommon to see “ComfyUI artist or engineer” listed as a job title on studio job boards.

Although video and image foundational models continue to improve, Yan claims that they are far from perfect, and a tool like ComfyUI will continue to be in high demand.

“In the world where AI slop is going to be everywhere, the Comfy version of human-in-the -loop approach is going to win out most of the eyeballs in the end,” he said.

ComfyUI’s competitors include Weavy, a startup that was acquired by Figma last year.