Documentation

npm install @uwu/sdk ethers

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@uwu/contracts/lib/UwuAttestationLib.sol";

contract MyCheckout {
    using UwuAttestationLib for UwuAttestationLib.Attestation;

    mapping(address => bool) public authorizedOracles;
    mapping(bytes32 => bool) public processedPayments;

    function processPayment(
        UwuAttestationLib.Attestation calldata att,
        bytes calldata signature
    ) external {
        bytes32 attHash = att.hash();
        
        require(!processedPayments[attHash], "Already processed");
        require(block.timestamp <= att.expiresAt, "Expired");
        require(att.riskScore < 70, "Risk too high");

        address signer = att.recoverSigner(signature);
        require(authorizedOracles[signer], "Invalid oracle");

        processedPayments[attHash] = true;

        // Your custom logic: mint NFT, credit balance, etc.
        _onPaymentVerified(msg.sender, att.inrAmount);
    }
}

1. Seller creates trade + enters UPI VPA
   → Escrow locks crypto on Push Chain

2. QR generated: upi://pay?pa={sellerVpa}&am={inrAmount}&tn={tradeId}
   → Seller shares QR with buyer

3. Buyer scans QR → pays via any UPI app (GPay, PhonePe, BHIM...)
   → INR goes directly to seller's bank account (uWu never touches fiat)

4. Oracle creates Setu AA consent → buyer approves in Setu popup
   → Setu fetches DEPOSIT transactions from buyer's bank (FIP)

5. Oracle matches CREDIT by amount ± 1% + UTR number
   → Signs attestation with Ed25519 key

6. Frontend submits attestation → contract verifies oracle signature
   → Escrow auto-releases crypto to buyer