I need a small, install-ready Shopify app that adds ABC PAY as a payment option at checkout. Flow I’m after • The shopper chooses “ABC PAY.” • A detailed, multi-step screen asks for their phone number. • An SMS OTP verifies the ABC account. • After the code is confirmed, the app shows the charge amount, checks wallet balance through the ABC PAY APIs, and—when funds are sufficient—moves the money to my store’s ABC wallet. Scope (lean MVP) – Build the private/custom Shopify app, register it, and supply installation instructions. – Wire every call to the existing ABC PAY REST APIs (auth, balance check, transfer). – Implement SMS OTP and the additional API verification step we discussed. – Basic admin page so I can enter my ABC PAY merchant credentials and toggle test/production. – Hand off well-commented source plus any Shopify setup steps (app listing, callback URLs, webhooks, etc.). -- Make the App ready to be used commercially. Experience required You’ve released Shopify apps before—ideally a payments or wallet gateway. If you can show a live or approved Shopify Payment App, you jump to the top of the list. Timeframe is short; I mainly need a working foundation I can extend later.