The Website Specification: practical technical criteria for websites

This specification brings together 178 topics covering a website’s technical responsibilities, including HTML, accessibility, security, performance, SEO, privacy and resilience. Each topic explains why it matters and how to implement it, with items marked as required, recommended, optional or to avoid.

A yes/no checklist turns those criteria into an audit that teams can revisit after fixes. Grounded in primary sources and platform-agnostic, the specification is also available to agents through a read-only MCP server, with no authentication required for its reference tools.