Call any API in three steps.

Every API in this directory speaks the same MPP / x402 payment handshake, so a single client and a single USDC wallet work for all of them.

1. Fund a Tempo wallet

   Hold a small USDC balance on Tempo. The same wallet pays every API in the directory — no per-service signup, no top-ups per provider.

2. Pick a payment client

   Use a tool that handles the 402 → Authorization: Payment retry for you:

   • mppx/client — Node / TypeScript SDK with one-shot and Tempo session support.
   • tempo request — CLI for one-shot paid requests.
   • AgentCash — payment layer for AI agents.
   • cURL — raw protocol; you mint the credential yourself.

3. Call any API in the directory

   Point your client at the API's endpoint. On the first call the server replies 402 Payment Required with a challenge; your client signs, retries, and you get back the response plus an x_receipt.

   tempo request https://demo-fx.example/v1/fx/EURUSD