Charge per request. Settle in USDC on Arc.

A buyer deposits USDC once, then signs an off-chain voucher for every call. The facilitator redeems it on Arc, where USDC is the native asset, so there is no separate gas token, no wrapping, no bridge.

Try the handshake How it works

Payment unit: USDC, 6 decimals
On-chain cost: 1 redeem per call
Signing: EIP-712 voucher

x402 handshake

ClientArcServer

GET /api/premium
no payment yet
—
402 Payment Required
accepts: 0.01 USDC to seller, via escrow gateway
402
sign voucher
EIP-712 (buyer, seller, amount, resource, nonce)
sig
GET /api/premium
X-PAYMENT: eyJ2b3VjaGVy…
↻
redeem(voucher, sig)
facilitator settles on Arc, USDC buyer → seller
tx
200 OK
X-PAYMENT-RESPONSE: { txHash: 0x9f3a… }
200

1 signature, 1 on-chain redeemsettles in USDC

Why escrow, not a transfer per call

High-frequency API consumption cannot pay a transaction fee on every request. Escrow moves the chain interaction off the hot path and gives the buyer a refund route and the operator a place for fees or disputes.

01Deposit

Prefund the escrow

The buyer deposits USDC into the gateway contract once. Signing a voucher afterward is free and instant.

02Sign

One voucher per request

Each call is authorized by an EIP-712 voucher over buyer, seller, amount, resource and nonce. No transaction to sign per request.

03Redeem

Settle on Arc

The facilitator verifies the signature and escrow balance, then redeems on-chain, moving USDC to the seller.

04Refund

Time-locked withdrawal

Unused balance is withdrawable after a cooldown, so in-flight vouchers cannot be rugged by an instant withdraw.

Run the real handshake

Live gateway on Arc Testnet0x049914870eF36AbC7c92E390937A012bEd1E1ec3

Connect a wallet on Arc to fund escrow and call the paid endpoint.