WCAG organises accessibility around four principles: content must be perceivable, operable, understandable and robust. The conformance levels are A, AA and AAA; AA is the usual legal and practical target. Most real-world failures are mechanical, not exotic — contrast ratios that fail, focus indicators removed for looks, inputs without labels, images with decorative or missing alt text.
The payoff is broader than compliance: keyboard-navigable interfaces work better for everyone, semantic HTML is what screen readers and answer engines both read, and high contrast helps on a phone in daylight. In the EU, accessibility for commercial websites moved from recommendation to legal requirement with the European Accessibility Act applying from June 2025.
Related terms
Core Web Vitals
Google's three field metrics for loading, responsiveness and visual stability, measured on real visits rather than in a lab.
Hydration
The step where JavaScript takes over server-rendered HTML in the browser and makes it interactive.
Static generation (SSG)
Rendering pages to HTML at build time, so a request is answered by handing over a file instead of running code.
The bench this belongs to
Full-stackIf you can describe it, we can build it. React and Next.js on the front, Python or Node behind, Postgres underneath, shipped to somewhere you can afford to run.
