Accept gasless stablecoin payments on your API. No minimums, no KYC, no human in the loop.
Start Building Free Read the Guidex402 builds on the HTTP 402 Payment Required status code. Your server controls the session, while the agent signs the transaction off-chain.
The agent requests access. Your server creates a session via CoinCircuit and responds with a 402, including deposit details.
The agent signs a gasless payment (EIP-3009, Permit2, or Solana) and hands the signed payload back to your server.
Your server submits the payload to CoinCircuit. We settle it on-chain, cover the gas fees, and you unlock the resource.
x402_handshake.http
1// 1. Agent requests your premium resource2GET /api/premium-data34// 2. Your server returns HTTP 402 with CoinCircuit session5HTTP/1.1 402 Payment Required6{7 "paymentRequired": {8 "chain": "base",9 "asset": "USDC",10 "amount": "1000000",11 "depositAddress": "0xabc...def"12 }13}1415// 3. Agent signs EIP-3009 gasless payment and POSTs it back16POST /api/premium-data/pay17{18 "scheme": "eip3009",19 "payload": {20 "from": "0xAgent...",21 "value": "1000000",22 "signature": "0xabcd..."23 }24}Native gasless transfers for USDC on Base and Arbitrum. The agent signs, you submit, we cover the gas.
Support for USDT and other ERC-20 tokens via Uniswap's universal Permit2 architecture.
Native fee abstraction on Solana for sub-second machine payments.
Dry-run signatures and timestamps via our verify endpoint before touching the blockchain.
Purpose-built for autonomous software that needs to pay for resources.
No 2FA, no CAPTCHAs, no bank logins. Built for pure machine-to-machine automation.
Agents pay fractions of a dollar per API call, below the minimum thresholds of traditional card processors.
Expose your paid tools to the growing Model Context Protocol ecosystem easily.
Settles on-chain in under 2 seconds. The agent pays, the resource unlocks immediately.
Build native AI monetization for your infrastructure using x402 and MCP.
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