Website resilience
Graceful failure — error pages, offline, redirects. Curated from the Website Specification — Resilience (CC BY 4.0).
Required
- Custom error pages (404, 500) that return the correct HTTP status, explain what went wrong in plain language, and offer a way forward without leaking implementation details.
Recommended
- Maintenance pages return
HTTP 503with aRetry-Afterheader. - Graceful degradation: core content and primary navigation keep working when JavaScript fails.
- Web app manifest (
manifest.json) declaring name, icons, start URL, theme colour, display mode. - Monitor uptime from outside your own infrastructure; run a status page on a separate host.
Optional
- Service worker serving a cached offline fallback page.
Full item list and rationale: https://specification.website/checklist/