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

> Source: <https://dev.to/kevin2003050666coder/what-a-seller-side-http-402-mcp-paywall-looks-like-36n>
> Published: 2026-09-01 10:29:38+00:00

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`