Set Up a Wallet

Give your AI agent a wallet for autonomous x402 payments.

Why a Wallet?

x402 payments require signing. Your agent needs a wallet with:

USDC on Base — the payment token
A private key — to sign payment proofs

Option 1: Coinbase AgentKit (Recommended)

Coinbase built AgentKit specifically for AI agents.

npm install @coinbase/agentkit

import { CdpClient } from "@coinbase/cdp-sdk";

const cdp = new CdpClient();
const wallet = await cdp.evm.createWallet();

console.log("Address:", wallet.address);
// Fund this address with USDC on Base

Why AgentKit:

No private key management
Built-in spending limits
Gasless transactions
x402 native support

→ AgentKit integration guide

Option 2: Raw Private Key

For custom integrations or full control.

Generate a Wallet

# Using cast (Foundry)
cast wallet new

# Or Node.js
node -e "
const { Wallet } = require('ethers');
const w = Wallet.createRandom();
console.log('Address:', w.address);
console.log('Private Key:', w.privateKey);
"

Store Securely

Never commit private keys to git. Use:

Environment variables
1Password / secrets manager
Hardware wallet (advanced)

export AGENT_PRIVATE_KEY="0x..."

Use in Your Agent

import { Wallet } from "ethers";

const wallet = new Wallet(process.env.AGENT_PRIVATE_KEY);
// Sign x402 payments with this wallet

Fund Your Wallet

Send USDC on Base to your agent's address.

From Coinbase

Open Coinbase app
Select USDC → Send
Enter your agent's address
Select Base network (not Ethereum!)
Send $5-10 to start

From Any Exchange

Most exchanges support Base withdrawals. Select "Base" or "Base Mainnet" when withdrawing USDC.

For Testing

Use Base Sepolia (testnet) with fake USDC:

Get test ETH from Alchemy faucet
Test USDC contract: 0x036CbD53842c5426634e7929541eC2318f3dCF7e

Check Your Balance

# Using cast
cast call 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 \
  "balanceOf(address)" YOUR_ADDRESS \
  --rpc-url https://mainnet.base.org

Or check basescan.org with your address.

Security Tips

Start small — $10-20 is plenty for testing
Use spending limits — cap per-transaction amounts
Separate wallets — each agent gets its own wallet
Monitor spending — check transaction history regularly

→ Spending controls guide

Next Steps

Your first payment — test the full flow
SDK reference — handles payment signing automatically