Q402 Architecture
Q402 is Quack AI’s gasless payment protocol built on EIP-7702 + EIP-712. It enables one-signature, gasless transactions with any existing ERC-20 token across 7 EVM mainnets — eliminating the ERC-3009 dependency that limits other gasless payment implementations.
Q402 evolved from Quack AI’s October 2025 launch of x402 BNB, the first unified sign-to-pay layer for BNB Chain’s Agent Economy. The same EIP-7702 + EIP-712 architecture has since been expanded into a unified multi-chain protocol, now live on Ethereum, BNB Chain, Avalanche C-Chain, X Layer, Mantle, Stable, and Injective EVM.
The Q402 roadmap includes future interoperability with the broader x402 ecosystem, enabling cross-protocol Agent Economy coordination.
Core Framework
Q402
7 EVM mainnets (Ethereum, BNB Chain, Avalanche C-Chain, X Layer, Mantle, Stable, Injective EVM)
EIP-7702 Delegated Execution + EIP-712 Witness Signatures
Unified sign-to-pay protocol — supports any ERC-20 with no token upgrades, fully gasless, policy-aware
Why Q402 Matters
Q402 provides a universal execution fabric for the Agent Economy, where governance, payments, and compliance operate under one rule-driven standard. It ensures that on-chain actions — from DAO votes to RWA settlements — can be completed with one verifiable signature and zero gas friction.
Architecture Overview
Signature Layer (EIP-712)
Captures user intent and cryptographically binds payment or governance data.
EIP-7702 Delegated Execution
Enables facilitators to submit Type 0x04 set-code transactions on user EOAs, supporting any ERC-20 without prior approval.
Facilitator Network
Manages gas sponsorship, monitors compliance, and maintains verifiable receipts.
Policy Engine Hooks
Validates every action against expiry, limits, and whitelisted conditions.
Audit Registry
Records signature-to-transaction mappings for on-chain traceability and reporting.
Q402 Production Deployment
Live deployment across 7 EVM mainnets with verified contract addresses
Supports any ERC-20 token without requiring upgrades
Achieved near-zero transaction failure rate
Reduced governance settlement latency by over 70%
Established compliance and audit-ready proof of execution
Production endpoint live at q402.quackai.ai with full SDK and developer platform
The Path Forward
Q402 continues to evolve. Upcoming developments include:
CCTP-native USDC support on Injective EVM (announced for Q2 2026)
Enhanced policy modules for regulated RWA flows
Cross-chain facilitator registry expansion
Deeper integration with AI Agent Governance for autonomous settlement
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