The Shopify App Store has over 8,000 apps — but sometimes none of them do exactly what you need. Custom Shopify app development allows you to build precisely the functionality your store requires, without the bloat, cost and reliability risks of stacking multiple third-party apps.
What Is Shopify App Development?
Shopify app development is the process of building software applications that extend Shopify's functionality. Apps connect to Shopify through its APIs — the Admin API, Storefront API, and Checkout Extensions API — to add features, automate processes, or integrate with external systems.
Apps can be built for a single store (private apps) or submitted to the Shopify App Store for any merchant to install (public apps).
Types of Shopify Apps
Private Apps (Custom Apps)
Private Shopify apps are built for a single specific store. They are not listed on the App Store and are not available to other merchants. Private apps are the right choice when:
- You need a custom integration with your internal ERP, CRM, or WMS system
- You need automation that processes your specific business logic
- You need functionality that is unique to your store or business model
- You want to build something that gives you a competitive advantage your competitors cannot easily replicate
Public Apps
Public Shopify apps are submitted to the Shopify App Store for installation by any Shopify merchant. Building a public app is a significant undertaking — requiring compliance with Shopify's review process, ongoing maintenance as Shopify updates its APIs, and a go-to-market strategy to drive installs.
Public apps make sense if you have identified a gap in the App Store and want to monetise the solution as a SaaS product.
Shopify Functions
Shopify Functions are a newer development primitive available to Shopify Plus merchants that allow custom server-side logic to run within Shopify's infrastructure. Functions can customise discount calculation, payment methods, shipping options, order routing and checkout validation.
Functions replace many use cases that previously required third-party apps or complex workarounds — and they run with significantly better performance because they execute within Shopify's own infrastructure.
When to Build a Custom Shopify App
Build a custom Shopify app when:
- No App Store solution exists for your specific need
- You need a direct integration with your internal software (ERP, POS, custom CRM)
- Third-party apps are costing too much at scale (custom app has a one-time development cost)
- App Store apps are causing reliability or performance issues on your store
- You need to automate a complex, multi-step business process specific to your operations
The Shopify App Development Process
- Scoping: Defining exactly what the app needs to do, the APIs required, data flows and edge cases
- Architecture: Choosing the right approach — embedded app, private app, Shopify Function, or Theme App Extension
- Development: Building against Shopify's APIs with full test coverage against a development store
- Review: Shopify's mandatory review process for public apps (private apps bypass this)
- Testing: End-to-end testing in a staging environment before production deployment
- Deployment & Maintenance: Live deployment and ongoing maintenance as Shopify updates APIs
How Much Does Shopify App Development Cost?
| App Type | Cost Range | Timeline |
|---|---|---|
| Simple private app / webhook | $1,500 – $5,000 | 1–3 weeks |
| Custom integration (ERP/CRM) | $5,000 – $20,000 | 3–8 weeks |
| Complex private app | $10,000 – $40,000 | 4–12 weeks |
| Public App Store app | $20,000 – $100,000+ | 8–24 weeks |
| Shopify Functions | $2,000 – $15,000 | 1–6 weeks |
How to Choose a Shopify App Developer
Look for developers with specific Shopify API experience — not just general web developers. They should be familiar with the Admin API, Storefront API, Checkout Extensions, and Shopify's OAuth flow. Ask to see previous Shopify app projects.
Our team of expert Shopify developers has built custom private apps and integrations for brands across the UK, USA and Australia. Contact us to discuss your requirements — we will provide a detailed technical scoping document and fixed-price quote. See also our Shopify Plus development services for Functions and checkout customisation.
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