Live on Base & Solana mainnet

Pay-per-call APIs,
one click away.

A live catalog of endpoints an agent — or a human — can run and pay for on the spot, settled on-chain in USDC over the x402 protocol. No keys, no signup, no SDK to learn. Inspect the schema, fill the inputs, click Run.

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Endpoints
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24h settled
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24h volume
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Success rate
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Unique payers
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01The catalog

Every endpoint below is live. Click one to inspect its schema and run it with a real on-chain payment.

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02Install

Paste one line into your <head>. Add data-x402-endpoint to any button. The modal handles the wallet, the 402 challenge, and settlement.

<!-- 1. Load once --> <script type="module" src="https://three.ws/x402.js"></script> <!-- 2. Any button becomes a paid call --> <button data-x402-endpoint="https://three.ws/api/x402/symbol-availability?ticker=AGENT" data-x402-merchant="three.ws" data-x402-action="Check ticker availability"> Check AGENT availability · $0.001 USDC </button>

03How it works

x402 is HTTP 402 Payment Required, with a manifest. The drop-in handles the entire dance — you never see it.

1

Buyer clicks

The modal opens, probes your endpoint, parses the 402 challenge, and shows the exact price and network.

2

Wallet signs

Phantom for Solana, MetaMask or Coinbase for Base. We build the SPL transfer or EIP-3009 authorization. One click.

3

Facilitator settles

PayAI or Coinbase CDP verifies and broadcasts on-chain. Your endpoint runs and streams the result back.

04Or call it from code

Same settlement, driven from JavaScript. The promise resolves with your endpoint's JSON and a settlement receipt.

const { result, payment } = await window.X402.pay({ endpoint: '/api/x402/symbol-availability', method: 'GET', body: { ticker: 'AGENT' }, merchant: 'Acme', }); // payment.transaction → on-chain tx hash // payment.payer → buyer wallet // result → your endpoint's JSON response

Agents pay autonomously with @x402/fetch or the MCP transport — no wallet UI, no API key. Re-downloadable goods support Sign-In-With-Wallet re-entry so buyers never pay twice for the same asset.

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