I’m looking for a developer who can create a Shopify app that slots in just before the native payment gateway selection during checkout. The goal is to control that hand-off step so I can process every transaction—credit or debit cards, digital wallets, and bank transfers—through my own logic before any purchase. Core requirements • Seamlessly inject into the checkout flow after a customer chooses a product or service, but before the gateway is called. • Handle and pass through all three payment methods exactly as Shopify expects so nothing breaks the customer experience. • Trigger automatic customer payment reminders for any orders that remain “Pending” with configurable timing inside the app settings. Scope of work 1. Architecture & setup – Register the app in a Shopify Partner account and configure necessary API scopes (Checkout, Payment Apps, Orders). – Use Shopify App Bridge and Polaris (or equivalent) so the admin UI feels native. 2. Core payment logic – Capture checkout data, apply any pre-processing we define, then forward the customer to the correct gateway. – Log success or failure states back to Shopify in real time. 3. Reminder engine – Admin can choose reminder intervals (e.g., 24 h, 72 h). – Emails or SMS should pull dynamic order details with liquid-style placeholders. 4. Dashboard & settings – Overview of transactions with filters by method, status, and date range. – Toggle payment methods on/off individually. 5. Testing & hand-off – Provide a test store setup, thorough QA scripts, and short Loom walk-through. – Deliver full source code (Node.js or Ruby preferred), environment variables template, and install guide. If you’ve built Shopify checkout or payment apps before, especially those that juggle multiple payment methods, I’d love to see them. Let me know your estimated timeline and any questions about the flow so we can get started right away.