PayNode Smart Contracts

Solidity-based non-custodial M2M (Machine-to-Machine) payment routing contracts, designed to provide ultra-low latency and high-verifiability payment infrastructure for AI Agents.

📜 License

Business Source License 1.1 (BSL-1.1)

• Allows all non-commercial use and commercial use under specific conditions.
• Automatically transitions to GPL-3.0-or-later 2 years after publication.

⚡ Stateless Design and Gas Advantages

PayNodeRouter adopts a Stateless architectural design, which is intended to optimize Gas consumption in M2M scenarios to the extreme:

1. Zero Storage (No SSTORE): The contract does not maintain the settlement status of orderId internally. This means we do not need to record whether an order has been paid via storage variables on-chain.
2. Event-driven: All payment proofs are emitted through the PaymentReceived event.
   • orderId is defined as indexed, facilitating fast retrieval by SDKs/backends using Bloom Filters.
3. Verification Cost Transfer: The "authenticity" of the payment is verified by the SDK side through interaction with the RPC. This keeps the Gas consumption of a single payment to basic transfer operations + event emission (approximately 60k-80k Gas).
4. Gas Comparison: Compared to traditional custodial/order management contracts (which typically require 150k+ Gas), PayNode's execution cost on Base L2 is reduced by more than 50%.

🔄 pay() Core Function Logic

The pay() function is the primary entry point of the protocol, with the following execution flow:

1. Input Parameter Validation:
   • Ensure merchant and token addresses are valid.
   • amount must be greater than 0.
2. Fee Calculation (Protocol Fee Split):
   • The protocol currently sets a fixed fee of 1% (100 BPS).
   • merchantAmount = amount * 99%
   • protocolFee = amount * 1%
3. Atomic Asset Transfer (SafeERC20):
   • Use IERC20.safeTransferFrom to deduct assets from msg.sender.
   • Assets flow directly to the merchant address.
   • Fees flow directly to the protocolTreasury address.
4. Log Emission (Emit Evidence):
   • Emit PaymentReceived(orderId, merchant, payer, token, amount, fee).
   • SDKs capture this event to confirm payment status.

🚀 Advanced Feature: payWithPermit

To completely eliminate the UX friction and multiple Gas consumptions brought by "Two-Step Approval" (Approve + Transfer) when AI Agents pay, the protocol supports EIP-2612 Permit. Agents only need to sign offline, and the SDK can complete all payment logic in a single transaction.

🛠️ Development Guide

Use the Foundry suite for testing and deployment:

# Compile
forge build

# Run full tests (including Fuzzing tests)
forge test -vvv

# Deploy to Base Sepolia
forge script script/Deploy.s.sol --rpc-url $BASE_RPC --broadcast