Accessibility at Scale: Patterns, Automation, and Contracts

Making one component accessible is one thing; keeping a whole app accessible as it grows requires patterns, automation, and clear contracts. This post covers how to scale a11y: design system rules, lint and test automation, and component API contracts.

Patterns and a design system

• Components: Buttons, links, form fields, modals, and tabs should have a single, accessible implementation. Use semantic HTML and ARIA where needed; document keyboard and screen-reader behavior.
• Focus: Define focus order (e.g. tab order, focus trap in modals, focus return on close). Put it in the component spec so every use is consistent.
• Color and contrast: Don't rely on color alone for meaning; ensure sufficient contrast (WCAG). Encode this in design tokens and component variants.

When every "button" or "modal" comes from the same place and follows the same rules, you don't have to re-decide a11y for every feature.