---

name: agentic-x402 description: Make x402 payments to access gated APIs and content. Fetch paid resources, check wallet balance, and create payment links. Use when encountering 402 Payment Required responses or when the user wants to pay for web resources with crypto. license: MIT compatibility: Requires Node.js 20+, network access to x402 facilitators and EVM chains homepage: https://www.npmjs.com/package/agentic-x402 metadata: {"author": "monemetrics", "version": "0.2.6", "openclaw": {"requires": {"bins": ["x402"], "env": ["EVM_PRIVATE_KEY"]}, "primaryEnv": "EVM_PRIVATE_KEY", "install": [{"id": "node", "kind": "node", "package": "agentic-x402", "bins": ["x402"], "label": "Install agentic-x402 (npm)"}]}} allowed-tools: Bash(x402:) Bash(npm:) Read

x402 Agent Skill

Pay for x402-gated APIs and content using USDC on Base. This skill enables agents to autonomously make crypto payments when accessing paid web resources.

Quick Reference

Installation

npm i -g agentic-x402

Once installed, the x402 command is available globally:

x402 --help
x402 --version

Setup

Run the interactive setup to create a new wallet:

x402 setup

This will:

1. Generate a new wallet (recommended) or accept an existing key
2. Save configuration to ~/.x402/.env
3. Display your wallet address for funding

Important: Back up your private key immediately after setup!

Manual Configuration

Alternatively, set the environment variable directly:

export EVM_PRIVATE_KEY=0x...your_private_key...

Or create a config file:

mkdir -p ~/.x402
echo "EVM_PRIVATE_KEY=0x..." > ~/.x402/.env
chmod 600 ~/.x402/.env

Verify setup:

x402 balance

Paying for Resources

When you encounter HTTP 402 Payment Required

Use x402 pay to make the payment and access the content:

x402 pay https://api.example.com/paid-endpoint

The command will:

1. Check payment requirements
2. Verify amount is within limits
3. Process the payment
4. Return the gated content

Automatic payment with fetch

Use x402 fetch for seamless payment handling:

x402 fetch https://api.example.com/data --json

This wraps fetch with x402 payment handling - if the resource requires payment, it's handled automatically.

Payment limits

By default, payments are limited to $10 USD. Override with --max:

x402 pay https://expensive-api.com/data --max 50

Or set globally:

export X402_MAX_PAYMENT_USD=25

Dry run

Preview payment without executing:

x402 pay https://api.example.com/data --dry-run

Creating Payment Links (Seller)

Create payment links to monetize your own content using x402-links-server:

Setup for link creation

Add to .env:

X402_LINKS_API_URL=https://your-x402-links-server.com

Create a link

Gate a URL:

x402 create-link --name "Premium API" --price 1.00 --url https://api.example.com/premium

Gate text content:

x402 create-link --name "Secret" --price 0.50 --text "The secret message..."

With webhook notification:

x402 create-link --name "Guide" --price 5.00 --url https://mysite.com/guide --webhook https://mysite.com/payment-hook

Get link info

x402 link-info 0x1234...5678
x402 link-info https://21.cash/pay/0x1234...5678

Command Reference

x402 balance

Check wallet balances.

x402 balance [--json] [--full]

x402 pay

Pay for an x402-gated resource.

x402 pay <url> [options]

x402 fetch

Fetch with automatic payment.

x402 fetch <url> [options]

x402 create-link

Create a payment link.

x402 create-link --name <name> --price <usd> [options]

Note: Either --url or --text is required. The link is deployed as a smart contract on Base.

x402 link-info

Get payment link details.

x402 link-info <router-address> [--json]

Environment Variables

Supported Networks

Payment Token

All payments use USDC (USD Coin) on the selected network.

• Base Mainnet: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
• Base Sepolia: 0x036CbD53842c5426634e7929541eC2318f3dCF7e

How x402 Works

1. Client requests a resource
2. Server responds with 402 Payment Required + payment details
3. Client signs a payment authorization (USDC transfer)
4. Client retries request with payment signature
5. Server verifies payment via facilitator
6. Server settles payment on-chain
7. Server returns the gated content

The x402 protocol is gasless for buyers - the facilitator sponsors gas fees.

Troubleshooting

"Missing required environment variable: EVM_PRIVATE_KEY"

Set your wallet private key:

export EVM_PRIVATE_KEY=0x...

Or create a .env file in your working directory, or install globally and use ~/.x402/.env.

"Payment exceeds max limit"

Increase the limit:

x402 pay https://... --max 50

Low balance warnings

Fund your wallet with:

• USDC for payments
• ETH for gas (small amount, ~0.001 ETH)

Network mismatch

Ensure your wallet has funds on the correct network:

• X402_NETWORK=mainnet → Base mainnet
• X402_NETWORK=testnet → Base Sepolia

Backup Your Private Key

Your private key is stored in ~/.x402/.env. If lost, your funds cannot be recovered.

Recommended Backup Methods

1. Password Manager (Recommended)

   • Store in 1Password, Bitwarden, or similar
   • Create a secure note with your private key
   • Tag it for easy retrieval

2. Encrypted File

   # Encrypt with GPG
   gpg -c ~/.x402/.env
   # Creates ~/.x402/.env.gpg - store this backup securely
   

3. Paper Backup (for larger amounts)

   • Write down the private key
   • Store in a safe or safety deposit box
   • Never store digitally unencrypted

View Your Private Key

cat ~/.x402/.env | grep EVM_PRIVATE_KEY

Recovery

To restore from backup:

mkdir -p ~/.x402
echo "EVM_PRIVATE_KEY=0x...your_backed_up_key..." > ~/.x402/.env
chmod 600 ~/.x402/.env
x402 balance  # verify

Security Best Practices

• Use a dedicated wallet — Never use your main wallet with automated agents
• Limit funds — Only transfer what you need for payments
• Set payment limits — Configure X402_MAX_PAYMENT_USD to cap exposure
• Test first — Use X402_NETWORK=testnet with test tokens before mainnet
• Protect the config — ~/.x402/.env has 600 permissions; keep it that way
• Never share — Your private key gives full access to your wallet

Links

• x402 Protocol Docs
• x402 GitHub
• npm: agentic-x402
• Base Network