Mercury is an MCP server + API where your AI agent pays for web data itself. It discovers a service, pays per call over x402 (or a free API key — no crypto needed), and gets back clean data plus an EIP-191 signed provenance receipt it can verify offline. 18 keyless services — fetch, extract, markdown, metadata, links, tables, feeds, sitemaps, DNS, diff, notarize — ~$0.003–0.02 a call, on 6 chains (Base, Polygon, Avalanche, Sei, IoTeX, peaq). npx mercury-x402-mcp for Claude / Cursor / Cline.
Server Config
{
"mcpServers": {
"mercury": {
"command": "npx",
"args": [
"mercury-x402-mcp"
]
}
}
}