x402-axios v2

This example demonstrates the simplest way to integrate Snack Money payments using axios with the x402 v2 payment client. Perfect for most web applications.

Overview

@x402/axios v2 wraps the popular axios HTTP client with automatic x402 payment negotiation. When the API returns 402 Payment Required, the client handles the payment flow automatically.

Features

✅ Base (EVM) and Solana (SVM) network support
✅ Automatic payment negotiation
✅ Simple axios-based API
✅ Type-safe TypeScript
✅ Minimal setup

Prerequisites

Node.js 18+
USDC balance on Base or Solana network
EVM private key (for Base) or SVM private key (for Solana)

Installation

npm install axios @x402/axios @x402/evm @x402/svm viem

Quick Start

1. Set Up Environment

Create a .env file:

# For Base network
EVM_PRIVATE_KEY=0x...
# For Solana network
SVM_PRIVATE_KEY=base58_key...
# Common
RECEIVER=your_x_username
AMOUNT=0.01

Important: Use your own X (Twitter) account as the receiver to test the integration safely.

2. Implement Base (EVM) Payment

Create base-send.ts:

import axios from "axios";
import { privateKeyToAccount } from "viem/accounts";
import {
  x402Client,
  wrapAxiosWithPayment,
  decodePaymentResponseHeader,
} from "@x402/axios";
import { registerExactEvmScheme } from "@x402/evm/exact/client";

// Load environment variables
const evmPrivateKey = process.env.EVM_PRIVATE_KEY as `0x${string}`;
const receiver = process.env.RECEIVER as string;
const amount = parseFloat(process.env.AMOUNT || "0.01");

async function sendPayment() {
  console.log("🚀 Starting Snack Money payment example with x402-axios v2\n");
  console.log("ℹ️  Network: Base (EVM)\n");

  // Create Base signer
  const evmAccount = privateKeyToAccount(evmPrivateKey);
  console.log("✅ Base signer created:", evmAccount.address);

  // Create x402 client and register EVM scheme
  const client = new x402Client();
  registerExactEvmScheme(client, { signer: evmAccount });
  console.log("✅ Registered EVM payment scheme\n");

  // Create axios instance with x402 payment interceptor
  const api = wrapAxiosWithPayment(
    axios.create({ baseURL: "https://api.snack.money" }),
    client
  );

  console.log(`💸 Sending ${amount} USDC to @${receiver} on X via Base...\n`);

  try {
    const response = await api.post("/payments/x/pay", {
      amount,
      currency: "USDC",
      receiver,
      description: "Payment via x402-axios v2 (Base)"
    });

    console.log("✅ Payment successful!");
    console.log("\n📊 Response:", JSON.stringify(response.data, null, 2));

    // Decode and display payment response header (v2 uses payment-response)
    const paymentResponseHeader = response.headers["payment-response"];
    if (paymentResponseHeader) {
      const paymentResponse = decodePaymentResponseHeader(paymentResponseHeader);
      console.log("\n🔐 Payment Response Details:", JSON.stringify(paymentResponse, null, 2));
    }
  } catch (error) {
    console.error("❌ Payment failed:", error);
    throw error;
  }
}

sendPayment();

3. Implement Solana (SVM) Payment

Create solana-send.ts:

import axios from "axios";
import {
  x402Client,
  wrapAxiosWithPayment,
  decodePaymentResponseHeader,
} from "@x402/axios";
import { registerExactSvmScheme } from "@x402/svm/exact/client";
import { createKeyPairSignerFromBytes } from "@solana/kit";
import bs58 from "bs58";

// Load environment variables
const svmPrivateKey = process.env.SVM_PRIVATE_KEY as string;
const receiver = process.env.RECEIVER as string;
const amount = parseFloat(process.env.AMOUNT || "0.01");

async function sendPayment() {
  console.log("🚀 Starting Snack Money payment example with x402-axios v2\n");
  console.log("ℹ️  Network: Solana (SVM)\n");

  // Create Solana signer
  console.log("🔧 Creating Solana signer...");
  const privateKeyBytes = bs58.decode(svmPrivateKey);
  const solanaSigner = await createKeyPairSignerFromBytes(privateKeyBytes);
  console.log("✅ Solana signer created:", solanaSigner.address);

  // Create x402 client and register Solana scheme
  const client = new x402Client();
  registerExactSvmScheme(client, { signer: solanaSigner });
  console.log("✅ Registered Solana payment scheme\n");

  // Create axios instance with x402 payment interceptor
  const api = wrapAxiosWithPayment(
    axios.create({ baseURL: "https://api.snack.money" }),
    client
  );

  console.log(`💸 Sending ${amount} USDC to @${receiver} on X via Solana...\n`);

  try {
    const response = await api.post("/payments/x/pay", {
      amount,
      currency: "USDC",
      receiver,
      description: "Payment via x402-axios v2 (Solana)"
    });

    console.log("✅ Payment successful!");
    console.log("\n📊 Response:", JSON.stringify(response.data, null, 2));

    // Decode and display payment response header
    const paymentResponseHeader = response.headers["payment-response"];
    if (paymentResponseHeader) {
      const paymentResponse = decodePaymentResponseHeader(paymentResponseHeader);
      console.log("\n🔐 Payment Response Details:", JSON.stringify(paymentResponse, null, 2));
    }
  } catch (error) {
    console.error("❌ Payment failed:", error);
    throw error;
  }
}

sendPayment();

4. Run the Example

For Base network:

npm run base
# or
npx tsx base-send.ts

For Solana network:

npm run solana
# or
npx tsx solana-send.ts

Expected Output

🚀 Starting Snack Money payment example with x402-axios

✅ Base signer created
💸 Sending 0.01 USDC to @username on X...

✅ Payment successful!

📊 Response: {
  "code": 200,
  "msg": "0.01 USDC sent successfully",
  "data": {
    "txn_id": "0xabc...def",
    "amount": 0.01,
    "receipt": "https://snack.money/x/username?txn=..."
  }
}

How It Works

Create Signer: Generate account from your private key (EVM or SVM)
Create x402 Client: Initialize the x402 client
Register Scheme: Register the appropriate payment scheme (EVM or SVM)
Wrap Axios: Add x402 payment wrapper
Make Request: POST to /payments/x/pay
Auto Payment: Client handles 402 response automatically
Retry: Request retries with payment proof
Success: Receive confirmation and receipt

Supported Endpoints

X (Twitter) Payments

await api.post("/payments/x/pay", {
  amount: 0.01,
  currency: "USDC",
  receiver: "username",
  description: "Payment description"
});

Farcaster Payments

await api.post("/payments/farcaster/pay", {
  amount: 0.5,
  currency: "USDC",
  receiver: "username",
  description: "Payment description"
});

GitHub Payments

await api.post("/payments/github/pay", {
  amount: 1.0,
  currency: "USDC",
  receiver: "username",
  description: "Payment description"
});

Configuration Options

Custom Axios Instance

const api = withPaymentInterceptor(
  axios.create({
    baseURL: "https://api.snack.money",
    timeout: 30000,
    headers: {
      "Content-Type": "application/json"
    }
  }),
  account as never
);

Request Options

const response = await api.post(
  "/payments/x/pay",
  {
    amount: 0.01,
    currency: "USDC",
    receiver: "username",
    description: "Payment description"
  },
  {
    timeout: 60000  // Custom timeout for this request
  }
);

Error Handling

try {
  const response = await api.post("/payments/x/pay", {
    amount: 0.01,
    currency: "USDC",
    receiver: "username"
  });

  console.log("Payment successful:", response.data);
} catch (error) {
  if (axios.isAxiosError(error)) {
    if (error.response?.status === 402) {
      console.error("Payment required but failed to process");
    } else if (error.response?.status === 404) {
      console.error("User not found");
    } else {
      console.error("API error:", error.response?.data);
    }
  } else {
    console.error("Unexpected error:", error);
  }
}

Common Errors

Insufficient USDC Balance

Ensure your wallet has enough USDC on Base network.
Check balance at: https://basescan.org/

Invalid Private Key

Private key must be a valid hex string starting with 0x
Format: 0x followed by 64 hex characters

User Not Found

The receiver username doesn't exist on the platform.
Verify the username is correct.

Testing Tips

Start small: Use 0.01 USDC for initial tests
Test on yourself: Send to your own X account
Check balance: Verify USDC balance before sending
Save receipts: Keep receipt URLs for records

Full Example Repository

View the complete example with configuration files: View on GitHub → The repository includes:

Complete TypeScript implementation
Environment configuration template
package.json with all dependencies
Detailed README

Next Steps

Try CDP SDK - MPC-based key management
Try fetch - Minimal dependencies
API Reference - Full API documentation
x402 Protocol - Understanding the protocol

Dependencies

{
  "dependencies": {
    "axios": "^1.7.9",
    "@x402/axios": "^2.0.0",
    "@x402/evm": "^2.0.0",
    "@x402/svm": "^2.0.0",
    "viem": "^2.39.3",
    "bs58": "^6.0.0",
    "dotenv": "^16.4.7"
  },
  "devDependencies": {
    "@types/bs58": "^5.0.0",
    "@types/node": "^22.0.0",
    "typescript": "^5.9.0"
  }
}

Introduction

CLI

SDK Examples

Overview

Features

Prerequisites

Installation

Quick Start

1. Set Up Environment

2. Implement Base (EVM) Payment

3. Implement Solana (SVM) Payment

4. Run the Example

Expected Output

How It Works

Supported Endpoints

X (Twitter) Payments

Farcaster Payments

GitHub Payments

Configuration Options

Custom Axios Instance

Request Options

Error Handling

Common Errors

Testing Tips

Full Example Repository

Next Steps

Dependencies

Learn More

Introduction

CLI

SDK Examples

​Overview

​Features

​Prerequisites

​Installation

​Quick Start

​1. Set Up Environment

​2. Implement Base (EVM) Payment

​3. Implement Solana (SVM) Payment

​4. Run the Example

​Expected Output

​How It Works

​Supported Endpoints

​X (Twitter) Payments

​Farcaster Payments

​GitHub Payments

​Configuration Options

​Custom Axios Instance

​Request Options

​Error Handling

​Common Errors

​Testing Tips

​Full Example Repository

​Next Steps

​Dependencies

​Learn More

Overview

Features

Prerequisites

Installation

Quick Start

1. Set Up Environment

2. Implement Base (EVM) Payment

3. Implement Solana (SVM) Payment

4. Run the Example

Expected Output

How It Works

Supported Endpoints

X (Twitter) Payments

Farcaster Payments

GitHub Payments

Configuration Options

Custom Axios Instance

Request Options

Error Handling

Common Errors

Testing Tips

Full Example Repository

Next Steps

Dependencies

Learn More