We are looking for an experienced Full Stack Developer to diagnose and resolve critical payment gateway issues in our web application. Scope of Work: Identify and fix payment failure and callback issues Debug order status mismatch after successful/failed transactions Ensure wallet balance and transaction records update correctly Verify webhook handling and server-side payment verification Fix invoice generation and transaction logging Secure payment flow and prevent duplicate or missing entries Test all scenarios (success, failure, timeout, refund) Optimize performance and error handling Technical Stack (Example – edit as needed): Frontend: React / HTML / CSS / JS Backend: PHP / Node.js / Laravel / Express Database: MySQL / MongoDB Payment Gateways: Razorpay / Stripe / PayPal / Cashfree / PhonePe Hosting: AWS / VPS / Shared Hosting Deliverables: Fully working payment flow Clean error-free code Proper transaction verification and logging Documentation of fixes Required Skills: Full Stack Development Payment Gateway Integration & Debugging API & Webhook Handling Security Best Practices Database Transaction Management Budget: Fixed or Hourly (Open for discussion) Timeline: Immediate start, fast turnaround preferred.