Freelance Job: Fix & Test E-Commerce Checkout Flow Overview Our Next.js e-commerce platform has a partially implemented checkout process that needs to be fully tested, debugged, and completed. The checkout currently uses Stripe for payments but has several issues preventing customers from completing purchases successfully. Your Mission Test the entire checkout flow end-to-end and fix all bugs preventing successful order completion. Ensure customers can: Add items to cart and proceed to checkout Complete payment via Stripe (card payments) Receive order confirmation See orders reflected in the admin dashboard Technology Stack Frontend: Next.js 14 (App Router), React, TypeScript, Tailwind CSS Backend: Next.js API Routes, Supabase (PostgreSQL) Payment: Stripe Payment Intents API Notifications: Twilio WhatsApp Known Issues to Address Currency detection/conversion not working properly Order confirmation emails not sending Payment flow has race conditions/timing issues Missing error handling for failed payments Incomplete order status tracking Cash payment option not fully functional Missing compliance features (3D Secure for EU customers) Deliverables Fully functional checkout flow (cart → payment → confirmation) Bug fixes with clear documentation of what was broken Test coverage for critical payment flows Brief handoff document explaining changes made Required Skills Strong Next.js & TypeScript experience Stripe integration expertise (Payment Intents, webhooks) PostgreSQL/Supabase knowledge Payment security & PCI compliance awareness Experience debugging production payment issues