One-time licenses instead of per-call fees: shipping a paid MCP server with x402

Описание и применение

Автор реализовал сервер MCP с однократной лицензией вместо оплаты за каждый вызов, используя протокол x402 и Base mainnet, что упрощает оплату для инструментов, используемых несколько раз в день.

Задача

Per-call billing for MCP servers creates a subscription‑like experience for tools used a few times a day, making micropayments cumbersome.

Результат

The MCP server successfully implements a one‑time license model, reducing payment friction for users and demonstrating that x402 can support license‑based billing.

Рабочий процесс

• 1. Client requests /api/comprar and receives a 402 response with payment details.
• 2. Client pays via an x402‑capable facilitator and retries with an X-PAYMENT header.
• 3. Server verifies payment, mints a license token, and returns it in a JSON response.
• 4. Client includes the x-license header on subsequent MCP calls.
• 5. Server validates the license hash stored in KV and enforces a 200‑call/month limit per license.

Доказательства

Everyone writing about paid MCP servers right now is charging per call.

Источник

a one-time 5 USDC payment on Base mainnet.

Источник

The license travels as a plain header on every MCP call: x-license: ct_...

Источник

Store only the hash. The KV namespace never sees the license token, only sha256(token).

Источник

Cap heavy buyers in the product, not in the contract. 200 calls per month per license.

Источник