Shopify app development cost: custom apps vs public apps

Shopify app development cost depends first on one question: is this a custom app for your own store, or a public app for the Shopify App Store? A custom app that keeps stock and orders in step with your ERP comes to about 380 hours in our illustrative estimate below, or $9,500 to $18,620 at the $25 to $49 an hour that Clutch's October 2026 guide says most development companies charge. A public app is a product, and costs several times more. To scope one, see Shopify app development services.

1Custom app or public app?

The cost to build a Shopify app, and the Shopify custom app cost in particular, depends first on this choice.

Most merchants need a custom app. Agencies and software companies building a product need a public one.

2A worked estimate: custom inventory and order sync

An illustrative example, not a quote: a merchant runs Shopify for its online store and an ERP for its warehouse. It wants stock levels pushed from the ERP to Shopify, orders pushed from Shopify to the ERP, and a daily report of anything that failed to sync.

At $25 to $49 an hour that is $9,500 to $18,620; at the $50 to $99 typical of US firms, $19,000 to $37,620. The sync logic, not the screens, takes most of the time: webhooks arrive out of order, APIs have rate limits, and two systems both believe they own the stock.

3A worked estimate: a modest public app

An illustrative example, not a quote: a public app that adds customer-specific price lists to a store.

That is $27,500 to $53,900 at $25 to $49 an hour. A public app also needs marketing, support staff and ongoing updates, which are business costs beyond the build.

4Shopify's revenue share

For public apps, Shopify's developer documentation (checked 23 October 2026) says developers keep 100% of their first $1,000,000 in gross app revenue and 85% of revenue above that, after registering with a one-time $19 fee. Developers above certain size thresholds pay 15% on all app revenue. Check the current terms before you build a business case.

5What drives the cost

1. Which APIs and webhooks the app uses, and their rate limits.
2. How many systems it connects, and how clean their data is.
3. Who owns which data: one source of truth per field avoids endless conflicts.
4. Admin screens: a background sync needs few; a merchant-facing tool needs many.
5. Public or custom: billing, multi-store support and review multiply the work.

6How to cut the cost

• Check the App Store first. An existing app may already do most of it.
• Sync one direction first, for example stock from ERP to Shopify, then add orders.
• Keep the app small: store only what you must, and let each system own its data.
• Build a reconciliation report from day one, so mismatches are caught by software, not customers.

7How to compare quotes

Ask each bidder: which system is the source of truth for each field; how rate limits, retries and duplicate webhooks are handled; what the reconciliation report shows; who hosts the app and who owns the code; and can we see a Shopify app you built that is running today?

8Costs after launch

A Shopify app keeps costing a little after it ships:

• Hosting for the app's back end and database. Small for a custom app, larger for a public app with many stores.
• API versions. Shopify releases new API versions on a regular schedule and retires old ones, so apps need periodic updates to keep working.
• Monitoring of sync failures, webhook errors and performance.
• Support, especially for public apps, where every merchant's store and theme is a little different.
• Changes, as your catalogue, your ERP or your processes change.

Budget for these every year. For a custom sync app they are modest; for a public app they are part of running a business.

9Build, buy or adapt

Try the cheaper routes first. Many merchants find that an existing app plus one small custom integration covers everything.

10Questions to answer before you request quotes

• Which system owns products, prices, stock, orders and customers?
• How fresh must stock be in Shopify: seconds, minutes or hours?
• How many products, variants and orders per day?
• What should happen when a sync fails?
• Who will look at the reconciliation report, and how often?

11A short glossary

• Custom app: an app built for one store or one merchant, installed directly rather than through the App Store.
• Public app: an app listed in the Shopify App Store, available to any merchant after Shopify's review.
• Admin API: Shopify's interface for reading and changing products, orders, customers and inventory.
• Webhook: a message Shopify sends to your app when something happens, such as a new order.
• Rate limit: the maximum number of API requests an app may make in a period; bulk updates must be paced.
• Idempotent update: an update that can safely be applied twice without doing harm, essential when webhooks repeat.
• Source of truth: the system that owns a piece of data; the others follow it.

Understanding these terms makes it much easier to read a Shopify quote and to see where the effort goes.

12The bottom line

For most merchants, the right budget is for a small custom app that keeps Shopify in step with the system that owns their stock and orders. A public app is a product, and deserves a product's business plan before anyone writes code.

13What Treevoxa charges

We quote Shopify work in US dollars and in writing, after mapping your data with you. The stock problem is one we solve in our own product, PharmaFlow, where a pharmacy's online store and counter share one stock record. See Shopify app development services, or our custom software development cost guide for software prices in general.