Shopify API & Custom App Development

Shopify's theme system and app ecosystem cover standard requirements. But when your e-commerce business has its own rules — customer-specific B2B prices, fulfilment logic across several warehouses, product data from an external PIM system — standard apps reach their limits. They can't be customised, cause performance problems through redundant API calls and, added up as subscriptions, cost more than a tailor-made solution.

We develop custom Shopify apps and API integrations: private apps for internal processes (ERP sync, fulfilment automation, custom reporting) and public apps with their own admin UI for complex requirements. Technically we work with Shopify CLI, the Admin GraphQL API and the Shopify Remix stack for embedded apps.

Typical projects: two-way ERP synchronisation (Shopify ↔ Weclapp, SAP, Xentral) for orders, stock levels and customer data. B2B pricing with customer-specific catalogues and volume discounts. Custom checkout extensions for special payment terms. And headless commerce architectures with Shopify's Storefront API and a Next.js front end for maximum performance and design freedom.

The economic side: three to five standard app subscriptions together cost €100–300 per month. A custom app that covers the same functions typically pays for itself within six to twelve months — and costs nothing after that.

When should you choose a custom app over a standard one? Three indicators: first, you use three or more App Store apps for related functions (e.g. one for pricing rules, one for stock sync, one for invoice export) — a custom app consolidates them and eliminates conflicts. Second, your ERP or CRM needs two-way real-time synchronisation — standard apps usually only work in one direction or with a delay. Third, you have B2B pricing with customer-specific catalogues, tiered prices or discount groups that go beyond Shopify's standard variant system.

Headless commerce with Shopify: for shops that need maximum performance and design freedom, we separate front end and back end. The Shopify admin stays the back end for orders, products and stock. The front end is built as a separate Next.js application on Shopify's Storefront API — with load times under one second, full SEO control and a design that isn't restricted by theme limitations.

Prices: a simple API integration (e.g. exporting orders to an ERP): from €2,500 with one to two weeks. A custom Shopify app with its own admin UI and complex logic: from €5,000 with three to six weeks. A headless storefront with Next.js: from €8,000 with four to eight weeks.

Problems we solve: three to five App Store apps that block each other and slow down the shop. Stock levels that drift apart between shop and ERP. B2B customers seeing the same prices as consumers because Shopify's standard pricing doesn't support customer-specific catalogues.

EA Digital Solutions has built custom Shopify apps for a range of industries — from e-commerce shops with complex fulfilment logic to B2B portals with customer-specific price groups. Our experience with the Shopify GraphQL API and the Remix stack means faster development and more robust apps.