I Built an API That AI Agents Pay For in USDC — Real-Time P2P Crypto Rates for 15 Latin American Currencies

Description and use

An API that AI agents pay for in USDC to receive real‑time P2P crypto rates for 15 Latin American currencies, requiring no keys or accounts.

Problem

AI agents cannot use traditional API keys or accounts, yet need access to real‑time P2P crypto rates for Latin American currencies.

Outcome

The API provides $0.002 USDC per call, zero human involvement, and supports Base mainnet and Sepolia. It enables AI agents to access critical market data without traditional authentication.

Workflow

• Agent requests GET /p2p/{fiat}
• Server returns 402 with payment details
• Agent signs a USDC payment authorization (EIP‑3009)
• Agent retries with X‑PAYMENT header
• Coinbase CDP facilitator verifies and settles on‑chain (~2 s)
• Agent receives JSON data

Evidence

Agents pay $0.002 USDC per call on Base. No API keys, no accounts, no signup. The payment IS the auth.

Source

The whole thing took an afternoon, and the agent economy needs more than weather APIs.

Source