What a seller-side HTTP 402 + MCP paywall looks like

A developer has released x402-micro-tollgate, an open-source Express process that acts as both an HTTP 402 reverse proxy and an MCP server, enabling agents to pay per API call without API keys. The tool returns a 402 Payment Required status for unpaid requests and proxies them after settlement, with MCP tools for server info, quotes, and proxied requests.

I needed agents to pay per call against an existing HTTP API without handing out API keys. x402-micro-tollgate is a thin Express process that is both an HTTP 402 reverse proxy and an MCP server. Unpaid gated routes default /v1 return protocol 402. After settlement, the request is proxied to UPSTREAM URL. /health stays free. Same process exposes MCP tools: server info free , get quote / proxy request paid . Demo no CDP keys : curl -i https://x402-micro-tollgate.onrender.com/v1/quote HTTP/1.1 402 Payment Required Self-host: npx x402-micro-tollgate Repo: https://github.com/kevin2003050666-coder/x402-micro-tollgate https://github.com/kevin2003050666-coder/x402-micro-tollgate npm: https://www.npmjs.com/package/x402-micro-tollgate https://www.npmjs.com/package/x402-micro-tollgate MCP Registry: io.github.kevin2003050666-coder/x402-micro-tollgate