The Problem with Traditional API Access

❌ API Keys

Secrets you share with strangers
Can be stolen or leaked
Require revocation and rotation
Don't scale for autonomous agents
Monthly invoices and payment rails

✅ x402 Protocol

Cryptographic proof, never shared
Sign with your wallet, nothing stored
Works with any EIP-712 capable wallet
Perfect for AI agents and automation
Pay-per-request, no subscriptions

How It Works

Make Request

Call API endpoint normally. Receive 402 Payment Required.

Sign Payment

Sign EIP-712 payment authorization with your wallet.

Get Response

Payment settles on-chain. API returns your data.

Infinite Scale

Continue making paid requests. No rate limits.

// Simple example
const response = await fetch('https://api.web3identity.com/api/price/eth');

if (response.status === 402) {
  // Client auto-handles payment signature
  const paidResponse = await window.x402Fetch(url, options, signerAddress);
  return paidResponse.json();
}

return response.json();

Why This Matters for Autonomous Agents

No Secret Management

Agents don't need to store or protect API keys. They sign with their wallet on every request.

Auditable Spending

Every payment is an on-chain transaction. Perfect transparency for autonomous operations.

Cross-Chain Compatible

Works with ETH, Base, and any EVM chain. Same protocol, different networks.

No Billing Integration

No monthly invoices, no payment processors, no subscriptions. Just sign and pay.

Instant Onboarding

Any wallet-enabled agent can start using paid endpoints immediately. Zero signup friction.

Rate Limit Freedom

Free tier: 100 calls/day. Paid tier: unlimited. Scale as much as you need.

Real-World Use Cases

🤖 AI Agents

Autonomous agents can pay for ENS resolution, price feeds, and identity lookups without human intervention.

📊 DeFi Protocols

Smart contracts can access off-chain data via CCIP-Read with x402 payment enforcement.

🔗 Cross-Chain Apps

Multi-chain applications can resolve identity and data across networks with unified payment.

Start Building with x402

1,616 free endpoints to explore. Pay only when you scale.

API Documentation Learn x402 Try Web3 Lookup

Pay for APIs Like You Pay for Gas