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Getting Started with X402 Echo Merchant

Use the Echo Merchant to validate your x402 client in minutes—no server to deploy.

Echo Merchant Website

Visit the Echo Merchant Website to test your client against a live x402-powered merchant.

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What you need

  • An x402 client implementation (see examples below)
  • A private key suitable for the network you’re testing

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Step 1 — Pick a client example

Start from one of the reference clients and run it locally: These examples already implement the x402 flow (handling 402, constructing the Payment Payload, retrying with PAYMENT-SIGNATURE, and decoding PAYMENT-RESPONSE).

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Step 2 — Point your client at the Echo Merchant

Visit the Echo Merchant Website to see the supported networks and endpoints for the Echo Merchant. For example:

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Step 3 — Run and observe

Run the client. You should see:
  1. Initial 402 Payment Required response with PAYMENT-REQUIRED header
  2. A retry with PAYMENT-SIGNATURE header containing your payment
  3. A 200 OK response with PAYMENT-RESPONSE header containing settlement details
The tokens you sent are refunded automatically and PayAI covers the fees.