USWDS (U.S. Web Design System) is the public-domain, open-source toolkit for U.S. federal government websites, built on progressively enhanced HTML so pages remain fully usable even if JavaScript fails to load.
It's in active use across 94+ agencies and 160+ websites at an estimated 1.1 billion page views, one of the largest real-world deployments of any design system documented here, and the "core HTML works without JS" principle is a genuinely rare, deliberate resilience guarantee.
Developers building U.S. government or civic services who need a proven, public-domain system that stays functional even when JavaScript fails to load.
It's public domain, not merely open source, meaning it can be used and modified with essentially no licensing restrictions at all, worth confirming for legal teams evaluating adoption outside government.
The US federal government's design system, with the tools and components behind accessible .gov sites.
