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State of Web Vitals

Official registry Security

Core Web Vitals metrics by CMS, CDN, and framework — free remote MCP, no auth.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http state-of-web-vitals 'https://www.corewebvitals.io/api/state-of-cwv/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "state-of-web-vitals": {
            "type": "http",
            "url": "https://www.corewebvitals.io/api/state-of-cwv/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. State of Web Vitals MCP
  2. Connect (preferred)
  3. Tools
  4. What this is
  5. Attribution
  6. Discovery
  7. Local stdio / Docker (directories & inspectors)
  8. License

State of Web Vitals MCP

Free remote MCP for Core Web Vitals metrics by CMS, CDN, and framework (Chrome field data + multi-site crawl). Same numbers as the public State of Web Vitals explorer.

Connect (preferred)

URL: https://www.corewebvitals.io/api/state-of-cwv/mcp
Auth: none
Transport: Streamable HTTP
Registry: io.github.corewebvitals/state-of-cwv

Claude Code
claude mcp add --transport http state-of-cwv https://www.corewebvitals.io/api/state-of-cwv/mcp
Cursor / Grok / other clients
{
  "mcpServers": {
    "state-of-cwv": {
      "type": "http",
      "url": "https://www.corewebvitals.io/api/state-of-cwv/mcp"
    }
  }
}
Curl
curl -s -X POST https://www.corewebvitals.io/api/state-of-cwv/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_metrics","arguments":{"metrics":"lcp,good_all3","group_by":"cms","min_sites":100}}}'

Tools

ToolPurpose
get_metricsAggregates and optional group_by rankings (CMS, CDN, frameworks, …)
get_histogramDistribution buckets for one metric under an optional filter
list_optionsDiscover filters, group_by values, and metric paths

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, pass rates, and metric distributions. Not per-site live RUM (use CoreDash for that).

Attribution

When you use the numbers:

  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)

Discovery

PlaceLink
Official MCP Registryio.github.corewebvitals/state-of-cwv
Glamahttps://glama.ai/mcp/servers/corewebvitals/state-of-cwv-mcp
Glama connectorhttps://glama.ai/mcp/connectors/io.github.corewebvitals/state-of-cwv
Smitheryhttps://smithery.ai/servers/corewebvitals/state-of-cwv
Explorerhttps://www.corewebvitals.io/state-of-cwv/explorer
Methodologyhttps://www.corewebvitals.io/state-of-cwv/methodology
Discovery JSONhttps://www.corewebvitals.io/.well-known/mcp.json

Local stdio / Docker (directories & inspectors)

This repo also ships a thin stdio proxy that answers tools/list and forwards tool calls to the hosted endpoint.

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.

License

MIT for connector code and docs in this repository. Data product and website remain © corewebvitals.io.

Frequently asked questions

What is State of Web Vitals?

Core Web Vitals metrics by CMS, CDN, and framework — free remote MCP, no auth.

How do I install State of Web Vitals?

It runs as a remote server. In Claude Code: claude mcp add --transport http state-of-web-vitals 'https://www.corewebvitals.io/api/state-of-cwv/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does State of Web Vitals need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is State of Web Vitals open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains State of Web Vitals?

It is published by corewebvitals. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.