Design, develop, and deploy a non‑custodial payment smart contract on EVM chains with funds routed directly wallet‑to‑wallet and an on‑chain fee mechanism. The contract must be immutable, publicly verifiable, and built with no custody or fund‑control functions.

Build and maintain the backend platform, including REST APIs, a merchant dashboard, real‑time transaction status, and webhook systems using Node.js and TypeScript.

Integrate blockchain transaction screening and AML/KYC tools such as Chainalysis and Scorechain into the payment flow.

Implement multi‑chain and multi‑token support for BTC, ETH, USDT across TRC20, ERC20, BEP20, Polygon, USDC, and other tokens.

Develop the point‑of‑sale software interface, including QR generation, rate‑lock logic, and gas abstraction for a smooth checkout.

Prepare the smart contract for independent third‑party audit and remediate findings before mainnet deployment.

Own security acros...