Developer Interface and SDK

The x402 SDK allows developers to integrate Sign-to-Pay and policy-aware execution into their own dApps, DAOs, or institutional systems. It provides simple libraries, API endpoints, and policy templates that make gasless and compliant execution accessible to any ecosystem.

SDK Modules

Module	Purpose
x402-Core	Base integration for EIP-712 signature and relay handling
x402-Policy	Hooks to apply or customize compliance logic
x402-Permit2 Adapter	Simplifies token compatibility for any ERC-20
x402-Facilitator API	Connects to relayer pools for sponsored execution
x402-Audit Tools	Access to signature receipts and on-chain tracking

Developer Workflow

[ Step 1 ]
Install SDK using npm or yarn.

[ Step 2 ]
Initialize Client with network, token, and policy configuration.

[ Step 3 ]
Generate Signature using x402-Core helper functions.

[ Step 4 ]
Submit Transaction through the Facilitator API.

[ Step 5 ]
Track Status using Audit Tools or the Governance Console.

Integration Benefits

• Rapid Deployment: Integrate in minutes without smart contract rewrites.

• Policy Templates: Prebuilt modules for KYC, treasury, and jurisdictional rules.

• Audit Friendly: Access real-time receipts for accounting or compliance teams.

• Multichain Support: Works with Q402 across all supported networks.

• Composable: Can link directly to Governance Intelligence or RWA modules.

For Institutions

Developers from financial institutions or RWA issuers can use the SDK to create autonomous compliance systems. By combining x402-Policy with Governance Intelligence, they can automate decision-to-execution pipelines while maintaining complete oversight.

The SDK brings enterprise-grade execution logic to Web3 builders and institutional teams alike.