Once UI is an open-source design system built for indie creators, small teams, and startups to fuel the next generation of web applications. It pairs an opinionated set of accessible React components with a flexible token system, so you can move from idea to polished product without fighting your tooling.Developed and maintained by Lorant and the Design Engineers Club, Once UI is free and licensed under the MIT license.
Vision
We believe great software shouldn't require a large team or a big budget. Our vision is a web where a single creator can ship products that look and feel as refined as those from companies many times their size.To get there, Once UI focuses on:
Compact, expressive syntax — describe intent with minimal markup and let smart defaults handle the rest.
Design consistency by default — tokens for color, spacing, typography, and motion keep every screen coherent.
An agent-first foundation — a system that AI tools can read, reason about, and extend reliably.
Mission
Our mission is to lower the barrier to building beautiful, responsive, and accessible web applications. Every decision — from API design to documentation — is measured against a simple question: does this make it easier for creators to ship?That means sensible defaults, predictable behavior, thorough documentation, and components that compose cleanly instead of locking you into rigid patterns.
Maintenance
Once UI is actively maintained as an open-source project. We ship regular releases with new components, fixes, and refinements, and we track upcoming work transparently:
Review what shipped in each release in the changelog, generated from the
repository's CHANGELOG.md.
Report bugs, request features, or open a pull request on GitHub.
We aim to keep the system stable and backwards-compatible, and to communicate breaking changes clearly when they're necessary.
Community
Once UI is shaped by the people who build with it. Whether you're filing your first issue or shipping your hundredth project, you're part of the community.
