Custom Shopify App Development: Process, Cost and When You Need One

Most custom app requests we get start the same way. A brand has six App Store apps stitched together with Zapier, one breaks whenever a product goes on pre-order, and someone in ops fixes orders by hand every Monday. Their question: “should we build our own?”

Sometimes the honest answer is no. When it is yes, Shopify app development in 2026 looks very different from two years ago: new apps are created in the Dev Dashboard or Shopify CLI, not the store admin, new public apps must use GraphQL, and most of the work lives in extensions that run inside Shopify. A focused custom app for one store usually takes 60 to 450 hours. At 2026 agency rates, that is roughly $1,500 to $92,000, depending more on who builds it than on what it does. Below: how we decide if you need one, how it is built, what it costs, and what changes if you sell it on the App Store.

Shopify app development at a glance

Shopify app development means building software that connects to a store through Shopify’s APIs and runs parts of itself inside the admin, storefront and checkout as extensions. You ship it one of two ways: custom distribution for one merchant, or public distribution through the App Store.

That choice is permanent: Shopify’s distribution documentation says you cannot change it once selected.

The Functions row comes from Shopify’s Functions API reference, which limits custom apps containing Functions to Plus stores. That one line changes a lot of project plans.

Do you actually need a custom Shopify app?

You need a custom Shopify app when no existing app, Flow workflow or metafield setup can express your logic, and working around it costs more each month than building and maintaining code. If either half is false, don’t build. We run every request through four questions first.

1. Does an App Store app already do 80% of it? Install it and live with the other 20% for a quarter.
2. Is it really a data problem? Product specs, size charts and store-locator data belong in metafields and metaobjects, no app needed. Our guide to Shopify metafields and metaobjects covers this.
3. Is it “when X happens, do Y” inside Shopify? That is Shopify Flow territory.
4. Does it need to change checkout, pricing or delivery logic, or connect to a system nothing else supports? That is where a custom app earns its cost.

Requests that genuinely need code are usually ERP or warehouse syncs, discount, shipping or payment rules beyond the built-in settings, internal admin tools, and B2B workflows. Replacing old Shopify Scripts is now Functions work, and our Scripts to Functions migration guide walks through it.

Custom Shopify app vs public app (and what happened to the Shopify private app)

A custom Shopify app serves one merchant and skips App Store review. A public app serves many and must pass review. The old “Shopify private app” is gone: private apps were deprecated in January 2022 and converted to custom apps by January 20, 2023, per the same distribution page.

The 2026 change most guides still miss

Store owners used to click “Develop apps” in the admin and copy an access token. That route is closed for new apps. Shopify’s Help Center page on custom apps says custom apps are now created in the Dev Dashboard, and apps created before January 1, 2026 are “legacy custom apps”. They keep working, but cannot use extensions, App Bridge or Shopify billing.

For internal integrations on your own stores, the old pasted token is replaced by the client credentials grant: your server swaps the app’s client ID and secret for a token that lasts 24 hours. It only works for apps your own organization develops.

Which one should you build?

• Build custom if the logic is specific to your business, catalog or back-office systems. This is most projects we see.
• Build public if hundreds of merchants share the problem and you are ready to run a software product: support, billing, reviews and quarterly API updates.
• Don’t build public just to get Functions on a non-Plus store. That is App Store review and compliance work for an audience of one.

What a 2026 Shopify app is made of

A modern Shopify app is two things: a small web app you host, which calls the GraphQL Admin API and receives webhooks, and extensions that Shopify hosts and runs inside its own surfaces. On most projects we build now, the extensions carry the merchant-facing value.

The backend and the API

Shopify CLI scaffolds the backend. shopify app init with the React Router template gives you authentication, a local Prisma SQLite database, and a tunnel to a development store via shopify app dev, per Shopify’s scaffolding guide.

Build against GraphQL from day one. Shopify’s REST Admin API reference says REST has been legacy since October 1, 2024, and new public apps must use only the GraphQL Admin API from April 1, 2025. Custom apps can still call REST, but a REST-based app is technical debt the day it ships.

The extensions

• Theme app extensions add app blocks and embeds to Online Store 2.0 themes, so merchants place your feature in the theme editor without editing theme.liquid. Per Shopify’s theme app extension docs, one integration works across themes.
• Checkout UI extensions add fields, banners and upsells to checkout. Extensions on the information, shipping and payment steps are limited to Plus stores. We cover the options in our checkout customization guide.
• Functions run custom discount, delivery, payment, cart validation and order routing logic as WebAssembly inside Shopify.
• Admin, POS and customer account extensions put actions on order and product pages, in the retail app, or in customer accounts.

Limits shape the design. UI extensions have a 64 KB compressed bundle limit. A Function’s compiled binary can be at most 256 kB and it gets 11 million instructions for carts up to 200 line items, per the Functions reference. Theme app extensions are capped at 100 KB of Liquid. You cannot ship a heavy bundle into checkout, and should not want to.

How to build a Shopify app: the process we follow

To build a Shopify app properly, write the spec first, prove the riskiest extension on a development store, then build the admin UI and integrations around it. Our sequence, with typical share of hours:

1. Discovery and spec (8 to 12%). Rules, edge cases and data sources, written as test cases with real carts and expected results.
2. Spike the risky part (5 to 10%). A throwaway Function first, to confirm its input query can fetch what the logic needs.
3. Scaffold and pipeline (5%). CLI project, staging and production app configs, CI deploys with shopify app deploy.
4. Extensions (30 to 40%). Functions, theme blocks, checkout or admin UI. Usually the largest line.
5. Admin UI and data (15 to 25%). Settings pages, with storage in metaobjects where possible.
6. Integrations and webhooks (0 to 30%). Zero for a checkout app, the biggest line for an ERP sync.
7. QA on a development store (10 to 15%). Real checkouts, every rule in the spec, uninstall and reinstall.
8. Release and handover (3 to 5%). Production install, monitoring, runbook.

Shopify app development cost in 2026

Shopify app development cost is hours times a rate. Our planning ranges run from 60 hours for a simple admin tool to 1,500 or more for a public app. Rate is the bigger lever: the same project can cost five times more at a US agency than an Indian one.

US mid-level agency work runs $120 to $205 an hour in Second Talent’s October 2026 tables. On Clutch’s Indian Shopify agency ranking, 23 of the 29 we counted list under $50 an hour, so we use $25 to $50.

One agency guide puts custom builds at $5,000 to $200,000 or more, inside our ranges. What the top-ranking guides don’t show is the hours, and hours are what you can check on a quote.

Worked example: a delivery-rules app for a Plus furniture brand

A hypothetical but realistic project. Say you sell bulky furniture on Shopify Plus, your carrier cannot do white-glove delivery to about 1,200 remote postcodes, and customers keep choosing it anyway. You want:

• A Delivery Customization Function hiding white-glove delivery for those postcodes
• A theme app block showing which delivery options a postcode gets
• An admin page to upload the postcode list, stored as a metaobject

At a US agency rate of $150 an hour, that is $27,900. With a hybrid team (40 hours of US-side spec and QA at $150, 146 build hours at $40) it is $11,840. The logic runs inside Shopify and the config lives in a metaobject, so there is almost nothing to host. Ongoing, budget about 16 hours a year for API version updates and small fixes. And note: as a custom app with a Function, it only works because the store is on Plus.

Running costs after launch

Shopify ships a new API version every quarter and supports each for at least 12 months, per its versioning policy. So every app needs at least one update a year, plus backend hosting if it has one. Our Shopify app development retainers are mostly this: version bumps, small changes and watching Dev Dashboard logs.

Public app economics: revenue share and fees

On the App Store, you keep 100% of your first $1 million in lifetime app revenue and pay 15% above it. A 2.9% processing fee plus tax applies to all billing, and there is a one-time $19 registration fee, all per Shopify’s revenue share page.

Three details matter:

• It is lifetime, not annual. Revenue from January 1, 2025 counts toward the $1M, and it never resets. Shopify announced the switch in its June 2025 changelog.
• It is gross. Refunds are not deducted from revenue share.
• Large developers pay 15% on everything: $20M+ in App Store revenue last year, or $100M+ company revenue.

Worked through: at $2M lifetime revenue, you pay $58,000 in processing and $150,000 in revenue share on the second million, an effective 10.4%. At $10M it is 16.4%. Below $1M, development and support will cost you far more than Shopify’s cut.

App Store review and Built for Shopify

A public app must pass review against the App Store requirements checklist. Reviews have been slow in 2026, so plan weeks, not days. Built for Shopify is a higher bar you apply for once the app has traction.

What review checks most often

• Billing through Shopify. App Store apps must use Shopify billing. For new apps the default is Shopify App Pricing, where Shopify hosts plans, trials and upgrades, per the billing docs explain.
• Embedded auth. App Bridge and session tokens, with no reliance on third-party cookies or pop-ups.
• Three compliance webhooks. Every App Store app must handle customers/data_request, customers/redact and shop/redact, even with no personal data stored, per Shopify’s privacy compliance guide.
• A complete listing. Name of 30 characters or fewer, 3 to 6 screenshots, a privacy policy, a demo store and a reviewer screencast.
• No APIs due for removal within 90 days.

On timing: in April 2026 Shopify staff acknowledged on the developer forum that submission volume had outgrown the review process. Developers there quote emails promising “up to 14 business days” and report longer waits. We plan four to eight weeks between submission and launch.

Built for Shopify

Built for Shopify is a status for apps meeting higher quality and performance standards. You need 50 net installs from active paid shops and 5 reviews, and your embedded admin pages must hit an LCP of 2.5 seconds or less, CLS of 0.1 or less and INP of 200 ms or less at the 75th percentile, and your storefront impact can cost no more than 10 Lighthouse points. Those numbers are on the Built for Shopify requirements page.

The payoff is a badge, a search filter, a ranking boost and priority review for future apps. Design for these numbers from the start.

What to ask before you hire someone to build it

Hire the team that asks about your rules and edge cases before talking about technology. A good partner can tell you in the first call whether your idea needs Plus and which extensions it needs. Then ask: will it run on our plan, is it GraphQL only, where does configuration live, will the app sit in our own Dev Dashboard organization, and what does a year of maintenance cost? Our guide on how to hire a Shopify developer has more screening questions.

Frequently asked questions

What we’d do first

Write the problem down as real examples: this order, this cart, and what should have happened. Run it through the four questions. If an app, Flow or metafields cover it, you have saved thousands. If not, you now have the spec a developer needs.

Check your plan before you scope: if the idea needs a Function or checkout steps and you are not on Plus, settle that first. And build for one store before dreaming about the App Store. A custom app that solves your own problem well is the best evidence others might pay for it.

We have built Shopify features for brands like EcoFlow, Delsey, MyHarry and Greatvacs. For a second opinion on whether your idea needs code, talk to our Shopify app development team.