I left Figma to build a diffusion-based UI design tool

Hey hn, this has been something I've been working on for the last few months and is finally robust enough to really show off.I've been pretty tired with the design outputs of LLMs for a while, and I've always thought diffusion offered much more creative / on brand design outputs, even before they were able to render text.I had enough conviction for this to leave my role over at Figma to build Diffui. The goal is to allow for you to design your full web app as quickly as possible, in a figma-like interface, and then hand that off to an agent to build. The page shows some interactive examples. Happy to be an open book here and chat about the approach, the process, etc!

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FL score

62

out of 100

Verdict

VALIDATE

high confidence

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Diffusion-based UI design tool that generates on-brand designs faster than LLMs, targeting designers who want to hand off to code agents.

The pain

Designers spend hours iterating on UI mockups. Current AI design tools (LLM-based) produce generic, off-brand outputs. Handoff to developers still requires manual translation or cleanup.

The gap

No tool currently combines diffusion model quality for visual design with a collaborative design interface and seamless code generation. Figma dominates design but lacks AI-native generation. Code agents exist but need better design inputs.

Build angle

Start by proving diffusion generates meaningfully better designs than LLMs on real design briefs. Then validate whether designers actually want to use this vs. Figma + manual handoff. The code generation piece is secondary, focus on the design quality first.

Strengths

  • Founder has deep Figma credibility and understands the design tool market from inside
  • Diffusion models do produce more visually coherent outputs than LLMs for image generation
  • Addresses a real frustration with current AI design tools
  • Timing aligns with improving diffusion model control and text rendering
  • Clear positioning against both Figma (speed) and LLM tools (quality)

Risks

  • Designers may not trust AI-generated designs enough to use them as primary output, they may only want it for inspiration
  • Figma could integrate diffusion models themselves within 12-18 months, eliminating the differentiation
  • The code generation handoff is unproven, agents still struggle with complex UI logic and accessibility
  • Diffusion models have licensing and IP concerns that could limit commercial viability
  • Market may be too small: only designers willing to use AI for core work, not the broader design tool market
  • Requires building both a design interface and training/fine-tuning diffusion models, high technical complexity

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