Ethereum Payment Gateway with Fraud Detection

I’m putting together a consumer-to-business payment gateway that runs entirely on Ethereum. The goal is for any online shop or SaaS platform to accept on-chain payments in ETH or ERC-20 tokens and receive instant confirmation through a simple API or Web3 hook, with built-in fraud checks before funds reach the merchant.

Here’s the flow I have in mind: a shopper clicks “Pay with Crypto,” the gateway spins up a one-time smart-contract address, watches the chain for the deposit, runs fraud-detection logic (velocity limits, address reputation, basic AML heuristics), and then notifies the merchant’s backend via webhook or GraphQL subscription. Successful transactions should settle directly to the merchant’s wallet; failed or flagged payments must trigger a callback we can act on.

I’m comfortable on the product side but need a Solidity/Web3 engineer who can deliver production-ready code, a lightweight Node.js or Python service that talks to the chain, and a small front-end demo so merchants can see it working end-to-end.

Deliverables:
• Audited Solidity smart contract(s) that handle consumer-to-business payments
• Fraud-detection module integrated into the off-chain service
• REST or GraphQL API with webhook callbacks for payment status
• Minimal front-end demo and clear setup docs (testnet first, then mainnet deployment)

If you’ve built gateways, DeFi tools, or anything similar on Ethereum and can hit these points quickly, let’s talk.