Shopify App and Website Build

I want to launch a compact but polished e-commerce presence made up of two parts:
• a mobile app for iOS and Android
• a responsive website connected to a Shopify storefront

The catalogue is small—about 20 products—so the focus is on a clean shopping flow, fast load times and an intuitive design rather than heavy-duty inventory features. I already chose Shopify as the platform, so every element of the build should make full use of Shopify’s native checkout, product management and payment integrations while keeping the look and feel on brand.

Deliverables
• Fully designed, live Shopify site with all 20 products uploaded, variant options set, taxes and shipping rules configured.
• Mobile app (iOS & Android) that mirrors the website catalogue, pulls real-time product data from Shopify and routes customers to Shopify’s secure checkout.
• Basic analytics setup (e.g. Google Analytics or Shopify reports) to track traffic and sales.
• Handover package: design source files, code repository, brief video or doc explaining how to add new products and fulfil orders.

Acceptance criteria
• End-to-end purchase can be completed without errors on both web and app.
• Product pages load in under three seconds on a standard 4G connection.
• App successfully passes store review guidelines for Apple App Store and Google Play.

Please outline your proposed tech stack for the app, any past Shopify builds you can reference, and an estimated timeline so I can get this live as soon as possible.