State of Web Vitals MCP

Free MCP for Core Web Vitals and technique metrics from Chrome field data plus a multi-site crawl. Same numbers as the public State of Web Vitals explorer.

Hosted endpoint (preferred): https://www.corewebvitals.io/api/state-of-cwv/mcp
Registry: io.github.corewebvitals/state-of-cwv
No install, no API key for the remote URL.

This repo also ships a stdio proxy (Dockerfile) for directories and inspectors that need a container that starts and answers tools/list. The proxy forwards to the hosted endpoint.

What this is

The State of Web Vitals measures Core Web Vitals and web-tech techniques across many real websites (Chrome field data + crawl). Use it for platform rankings (CMS, CDN, frameworks), pass rates, and metric distributions — not per-site live RUM. For live per-site RUM, use CoreDash.

Related MCP server: APIMesh MCP Server

Tools

Authentication

None. Public research data. Credit corewebvitals.io when you use the numbers.

Connecting (remote — recommended)

Claude Code

claude mcp add --transport http state-of-cwv https://www.corewebvitals.io/api/state-of-cwv/mcp

Cursor / Grok / clients

{
  "mcpServers": {
    "state-of-cwv": {
      "type": "http",
      "url": "https://www.corewebvitals.io/api/state-of-cwv/mcp"
    }
  }
}

Connecting (local stdio / Docker)

npm install
npm start

docker build -t state-of-cwv-mcp .
docker run --rm -i state-of-cwv-mcp

Optional: STATE_OF_CWV_MCP_URL overrides the upstream endpoint.

Attribution

When quoting or basing conclusions on this data:

1. Credit corewebvitals.io / The State of Web Vitals

2. Link https://www.corewebvitals.io/state-of-cwv when links are allowed

Short line: Data: State of Web Vitals (corewebvitals.io)

Links

• Explorer: https://www.corewebvitals.io/state-of-cwv/explorer

• Methodology: https://www.corewebvitals.io/state-of-cwv/methodology

• Discovery: https://www.corewebvitals.io/.well-known/mcp.json

• Official MCP Registry: io.github.corewebvitals/state-of-cwv

• Glama: https://glama.ai/mcp/servers/corewebvitals/state-of-cwv-mcp

License

Documentation and connector code in this repository are MIT. The data product and website remain © corewebvitals.io.