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.