Builds consistent React apps for developers and AI agents
Once UI is an open-source design system for building polished React products with less repetitive code. Compose layouts with readable primitives, use a shared system of components and design tokens, and keep the result consistent as your product grows. Version 2.0 gives both you and your coding agent a clearer way to work. Its component catalog, compact rules, and task guides help agents use the system correctly; its foundations and predictable APIs make the output easier for you to understand.
Hey Product Hunt, I’m Lorant, the creator of Once UI.
I started Once UI because I wanted independent builders to have the kind of design infrastructure larger teams can afford to maintain. Over time, it became clear that this matters even more when an agent is helping write the code. Generating a screen is easy. Keeping the next twenty screens coherent is the real challenge.
So for 2.0, we worked on the system underneath: clearer foundations, more consistent components and APIs, and a compact set of rules and examples that coding agents can actually use. You can build with an agent, write everything yourself, or move between the two while staying in control of the result.
The core is open source. I’d love to see what you build with it, and I’d especially value honest feedback from anyone who has tried using a design system across a real product. Where does the system help, and where does it get in your way?
About Once UI 2.0 on Product Hunt
“Builds consistent React apps for developers and AI agents”
Once UI 2.0 launched on Product Hunt on September 25th, 2026 and earned 70 upvotes and 1 comments, placing #19 on the daily leaderboard. Once UI is an open-source design system for building polished React products with less repetitive code. Compose layouts with readable primitives, use a shared system of components and design tokens, and keep the result consistent as your product grows. Version 2.0 gives both you and your coding agent a clearer way to work. Its component catalog, compact rules, and task guides help agents use the system correctly; its foundations and predictable APIs make the output easier for you to understand.
On the analytics side, Once UI 2.0 competes within Open Source, Developer Tools, Artificial Intelligence, GitHub and Vercel Day — topics that collectively have 1.1M followers on Product Hunt. The dashboard above tracks how Once UI 2.0 performed against the three products that launched closest to it on the same day.
Who hunted Once UI 2.0?
Once UI 2.0 was hunted by Lorant One. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
Lorant One