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OPEN X402 PAYMENT INFRASTRUCTURE

Payments that move at internet speed.

Create a reference. Let any wallet sign. Settle USDC on-chain. x402 PaySDK gives apps and merchants one non-custodial path from link or QR to verified payment.

Start building Explore protocol
Protocol online x402pay://x402.pwp.sh/receive/0x71…a3?ref=pay_4f2 BASE · USDC
PaymentRef 24.00 USDC Receiver · 0x71F8…09A3
Settlement confirmed0x8d7…41c
Non-custodialStateless by defaultEIP-3009Cloudflare ready

CLEAR TRUST BOUNDARIES

One protocol. Three focused SDKs.

Each package does one job and stays inside its own security boundary.

PAYER

Pay SDK

Wallet-native payer flow

Resolve requirements, verify signed offers, request EIP-712 authorization, and submit payment.

RECEIVER

Receive SDK

References, not custody

Create portable PaymentRef records for QR codes, links, apps, and APIs.

MERCHANT

Merchant SDK

Backend payment operations

Onboard merchants, verify receipts, process notifications, refund, and reconcile.

SCHEMA IS THE PROTOCOL

From a reference to chain truth.

The gateway coordinates verification and settlement without ever holding payer keys or funds.

REF PaymentRef
SIG Wallet signer
402 x402 gateway
TX EVM / USDC
PAYER INTEGRATION
import { pay } from 'x402-paysdk/pay';

const settlement = await pay({
  refUrl,
  paymentId: crypto.randomUUID(),
  wallet
});
settled8453 / 0x8d7…41c

BUILT TO FAIL CLOSED

Security is part of the payment path.

Signed context, payTo ownership proof, bounded RPC, SSRF-safe notifications, key rotation, and chain-backed verification are production gates, not optional add-ons.

Review security model

Build the shortest path to on-chain payment.

Start with a payer, receiver, or merchant integration and keep the wallet in control.

Read the documentation