Runtype

Check your website against The Website Specification.

Paste a URL and get a graded report card — what your page does well, what it’s missing, and exactly how to fix it.

~150 checks · HTML fetch + browser rendering · graded report

Try
How it works
The pipeline

From a URL to a graded report, in four steps.

The Website Specification is a community baseline for what a good website should ship — the HTML foundations, SEO, accessibility, security, performance, privacy, and agent-readiness signals every page is expected to have. We check your page against it automatically.

  1. 01

    Pick a URL

    Paste any public address. We normalise it to https:// and resolve redirects so the report reflects the page people actually land on.

  2. 02

    Fetch & render

    We pull the raw HTML, then render the page in a real browser via Cloudflare Browser Rendering — and probe /.well-known/ files, robots.txt, and DNS.

  3. 03

    Run ~150 checks

    Each check maps to a clause of the spec — from <!doctype> and canonical tags to TLS headers, axe-core a11y rules, and Core Web Vitals.

  4. 04

    Read the report

    A letter grade, per-category scores, and a row for every check with the evidence we found and a one-line fix linking back to the relevant spec section.

MCP server
For agents & editors

Run these checks from your AI agent.

The same engine is exposed as a Model Context Protocol server over Streamable HTTP (JSON-RPC) at /mcp. Point Claude, an IDE, or any MCP client at it to grade sites from inside your workflow.

  • check_website

    Run the full specification check against a URL and return the graded report as structured JSON.

  • get_spec_checklist

    Return the full catalogue of checks and the spec clauses they map to — useful as a reference or to plan fixes.

{
  "mcpServers": {
    "spec-checker": {
      "type": "streamable-http",
      "url": "https://spec-checker.runtype.app/mcp"
    }
  }
}

Endpoint: POST https://spec-checker.runtype.app/mcp · transport: Streamable HTTP · protocol: JSON-RPC 2.0.