curl -i "https://example.com/api/paid-endpoint"

{"x402Version":1,"accepts":[{"network":"base","maxAmountRequired":"2000",...}]}

PAYMENT-REQUIRED: <base64-encoded>
{"x402Version":2,"accepts":[{"network":"eip155:8453","maxAmountRequired":"2000",...}]}

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This creates a `.env` file with `WALLET_ADDRESS` and `WALLET_PRIVATE_KEY`.

npm install x402-fetch viem

npm install @x402/fetch @x402/evm viem

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import { wrapFetchWithPayment, createSigner, decodeXPaymentResponse } from "x402-fetch";

const privateKey = process.env.WALLET_PRIVATE_KEY as `0x${string}`;

// Use network string from 402 response: "base", "base-sepolia", "solana", etc.
const signer = await createSigner("base", privateKey);
const fetchWithPayment = wrapFetchWithPayment(fetch, signer);

const response = await fetchWithPayment("https://api.example.com/paid", { method: "GET" });
const data = await response.json();

// Check payment receipt
const paymentResponse = response.headers.get("x-payment-response");
if (paymentResponse) {
  const receipt = decodeXPaymentResponse(paymentResponse);
  console.log("Payment settled:", receipt);
}

import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const signer = privateKeyToAccount(process.env.WALLET_PRIVATE_KEY as `0x${string}`);
const client = new x402Client();
registerExactEvmScheme(client, { signer });

const fetchWithPayment = wrapFetchWithPayment(fetch, client);
const response = await fetchWithPayment("https://api.example.com/paid", { method: "GET" });

// Check payment receipt
const paymentResponse = response.headers.get("PAYMENT-RESPONSE");

// call-v1-endpoint.ts
import { wrapFetchWithPayment, createSigner, decodeXPaymentResponse } from "x402-fetch";

const privateKey = "0x..." as `0x${string}`; // Your private key
const walletAddress = "0x..."; // Your wallet address

async function main() {
  // Step 1: Check what version the endpoint uses
  const checkResponse = await fetch("https://example.com/api/data");
  if (checkResponse.status === 402) {
    const body = await checkResponse.json();
    console.log("x402 Version:", body.x402Version);
    console.log("Network:", body.accepts[0].network);
    console.log("Price:", body.accepts[0].maxAmountRequired, "atomic units");
  }

  // Step 2: Create signer with v1 network string
  const signer = await createSigner("base", privateKey); // Use network from response

  // Step 3: Wrap fetch and make paid request
  const fetchWithPayment = wrapFetchWithPayment(fetch, signer);
  const response = await fetchWithPayment("https://example.com/api/data");
  const data = await response.json();
  console.log("Response:", data);

  // Step 4: Check payment receipt
  const receipt = response.headers.get("x-payment-response");
  if (receipt) {
    console.log("Payment settled:", decodeXPaymentResponse(receipt));
  }
}

main().catch(console.error);

// call-v2-endpoint.ts
import { wrapFetchWithPayment, x402Client, x402HTTPClient } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const privateKey = "0x..." as `0x${string}`;

async function main() {
  // Step 1: Check what version the endpoint uses
  const checkResponse = await fetch("https://example.com/api/data");
  if (checkResponse.status === 402) {
    const hasV2Header = checkResponse.headers.get("PAYMENT-REQUIRED");
    console.log("Is v2:", !!hasV2Header);
  }

  // Step 2: Setup v2 client
  const signer = privateKeyToAccount(privateKey);
  const client = new x402Client();
  registerExactEvmScheme(client, { signer });

  // Step 3: Make paid request
  const fetchWithPayment = wrapFetchWithPayment(fetch, client);
  const response = await fetchWithPayment("https://example.com/api/data");
  const data = await response.json();
  console.log("Response:", data);

  // Step 4: Check payment receipt
  const receipt = response.headers.get("PAYMENT-RESPONSE");
  if (receipt) {
    console.log("Payment settled");
  }
}

main().catch(console.error);

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import { HTTPFacilitatorClient } from "@x402/core/http";
import { withBazaar } from "@x402/extensions";

const facilitatorClient = new HTTPFacilitatorClient({
  url: "https://api.cdp.coinbase.com/platform/v2/x402"
});
const client = withBazaar(facilitatorClient);

const response = await client.extensions.discovery.listResources({ type: "http" });

// Filter by price (under $0.01 = 10000 atomic units)
const affordable = response.items.filter(item =>
  Number(item.accepts[0].maxAmountRequired) < 10000
);

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{
  "x402Version": 2,
  "accepts": [...],
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "POST",        // <-- HTTP method
          "bodyType": "json",      // <-- Body format
          "body": {}
        }
      },
      "schema": {
        "properties": {
          "input": {
            "properties": {
              "body": {
                "properties": {
                  "urls": { "type": "array", "items": { "type": "string" } },  // Required field
                  "text": { "type": "boolean" }  // Optional field
                },
                "required": ["urls"]  // <-- Required fields listed here
              }
            }
          }
        }
      }
    }
  }
}

const response = await fetchWithPayment("https://example.com/api/endpoint", {
  method: "POST",  // From info.input.method
  headers: { "Content-Type": "application/json" },  // From info.input.bodyType
  body: JSON.stringify({
    urls: ["https://example.com"],  // Required field
    text: true  // Optional field
  })
});

curl -s -X POST "https://example.com/api/endpoint" -H "Content-Type: application/json" | \
  jq -r 'if .accepts then . else empty end' 2>/dev/null || \
  echo "Check PAYMENT-REQUIRED header for v2"

curl -si -X POST "https://example.com/api/endpoint" -H "Content-Type: application/json" | \
  grep -i "payment-required:" | cut -d' ' -f2 | base64 -d | \
  jq '{method: .extensions.bazaar.info.input.method, bodyType: .extensions.bazaar.info.input.bodyType, required: .extensions.bazaar.schema.properties.input.properties.body.required}'

curl -i -X POST "https://example.com/api/endpoint" -H "Content-Type: application/json"