**Pay-per-call API marketplace on Base (USDC).** x402-market lets AI agents discover and invoke any listed API end-to-end with one tool call. The MCP server handles HTTP 402 payment challenges automatically using your wallet, so Claude (or any MCP client) pays for API calls on its own. ## How it works 1. `list_catalog` — discover available paid APIs in the marketplace 2. `get_listing` — inspect endpoint schema, pricing, and usage notes 3. `pay_and_call` — invoke the API end-to-end; pays the seller via x402 / USDC on Base if a 402 challenge is returned 4. `claim_refund` — auto-judge refund for failed calls or >30s upstream latency ## Setup - `MCP_BUYER_PRIVATE_KEY` (required): Hot wallet on Base mainnet with a small USDC + ETH balance. **Use a separate wallet, not your main one.** - `MCP_MAX_PRICE`: Hard cap per call (USDC). Default `1`. - Other params have safe defaults. ## Links - npm: `@x402-market/mcp-server` - GitHub: https://github.com/AsaiShota/x402-market - Marketplace API: https://x402-market-api.lien-studio-akiyama.workers.dev
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How to connect
https://server.smithery.ai/lien-studio-akiyama/x402-market/mcpcurl -X POST https://server.smithery.ai/lien-studio-akiyama/x402-market/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'