x402 와 USDC 로 API 수익화

Pick the right resource

Do not start by charging every endpoint. Pick one resource where the value is obvious and the response is deterministic enough to price.

A clear resource boundary also makes it easier to debug payment mismatches and explain pricing to developers.

• Use a stable public URL
• Bind the rule to a specific HTTP method
• Set a price that makes sense per request
• Write a short description agents and developers can understand

Design the payment flow

The first request should return a 402 challenge when no valid payment payload is present. After payment verification succeeds, the same route can return the protected data.

This flow keeps API access stateless from the user perspective and avoids prepaid balances for small, high-frequency usage.

Operate it like billing infrastructure

Treat each paid request as a financial event. Store payment records, make retries idempotent, and expose clear logs for support and reconciliation.

• Verify resource URL and method exactly
• Reject expired payment payloads
• Deduplicate nonce or authorization identifiers
• Record settlement status and transaction hash