Payload

Turn any MCP server into a paid API — per-tool pricing, free quotas, and an append-only payment ledger, verified end-to-end against the real @modelcontextprotocol/sdk.

WHAT IT DOES: registerTool / callTool / listTools paid-tool registry with per-call payment enforcement; attachToMcpServer adapter for the official @modelcontextprotocol/sdk Server; per-tool pricing in USDC with free quotas (e.g. 3 free calls, then payment required); HMAC dev verifier for local testing + facilitator verifier for production x402 payments; append-only JSONL payment ledger; working runnable examples (paid server + paying client demo).

WHAT’S PROVEN: 15/15 tests green (9 unit + 6 integration) — unpaid calls rejected with payment-required, paid calls execute, tampered payments rejected.

REQUIREMENTS: Node.js 18+. Customer supplies their own x402 facilitator for production payments.

Developer tooling: processes payments for API/tool calls. Does not custody funds, execute trades, or provide financial advice.

LICENSE: Perpetual single-seat commercial license for your own commercial projects. No redistribution, resale, sublicensing, or public sharing. 7-day refund available if the product is materially not as described or cannot be made functional after reasonable support. Change-of-mind refunds are not available after download or access.

Support: kyler.simmons.partners@gmail.com — Sold by Payload. One-time price. Yours forever. No subscriptions, no lock-in.