Shopify App Development for Custom Apps and App Store Products

Shopify app development covers any software that adds features Shopify does not provide out of the box. For a merchant that might be a custom app that syncs orders with a warehouse system, a discount rule the admin cannot express, or a product configurator on the storefront. For a founder it might be a public app sold to thousands of stores through the Shopify App Store. This service sits within our Shopify development services, and we take on both kinds of project.

We bring hands-on experience from our own product. We co-build AM Jarvis, a SaaS suite for Shopify and WooCommerce stores that handles bulk product importing, bulk editing with preview and undo, and Google Merchant Center fixes. Working with large catalogs through Shopify's APIs every week teaches you where apps break, and we design around those limits from the start.

Our Shopify App Development Services

Custom App, Public App or an Existing App?

The cheapest app is the one you do not have to build. Before quoting, we check whether an existing App Store app or a native feature such as Shopify Flow already covers the requirement. When it does, we tell you and point you to it.

• Choose an existing app when the workflow is common, the app is actively maintained and its data access is reasonable for what it does.
• Choose a custom app when the process is specific to your business, involves sensitive data you do not want shared with a third-party vendor, or would need three separate apps glued together.
• Choose a public app when you are solving a problem many merchants share and want to build a product business around it, with support, billing and updates planned from day one.

How We Build Shopify Apps

1. Discovery sprint (1 to 2 weeks). We map the workflow, the data involved, the Shopify access scopes required and the extension surfaces that fit. The output is a written specification, an architecture outline and a fixed estimate for the build.
2. Architecture (inside the sprint, about 1 week). We choose the app framework, hosting and database, request only the access scopes the app needs, and design webhook handling so duplicate or out-of-order deliveries cannot corrupt data. Shopify documents that webhooks can arrive more than once, so every handler is written to be safe on repeat.
3. Build in short iterations (3 to 12 weeks). You get working increments on a development store every one to two weeks. Seeing real screens early catches misunderstandings while they are still cheap to fix.
4. Testing and review (1 to 2 weeks). We test install, uninstall and reinstall, large catalogs, API rate limits and failure cases such as expired sessions. Public apps also get the mandatory privacy webhooks and a pre-submission check against the App Store requirements.
5. Launch and upkeep (launch week, then ongoing). We deploy, monitor errors and hand over documentation. Shopify releases a new API version every quarter and supports each one for at least 12 months, so we plan version upgrades before old versions are retired.

A focused custom app usually sits at the short end of the build range, while a public app with billing, onboarding and several extensions sits at the long end, plus Shopify's review time.

Shopify App Development Deliverables and Signs the App Is Healthy

• Written specification. Features, user roles, access scopes, data stored, webhooks subscribed and extension surfaces, agreed before build.
• Source code in your repository. With a README, environment setup steps, automated tests and a deployment pipeline you can run without us.
• The deployed app. Hosted in accounts you own, with error monitoring, logs and alerts switched on.
• A runbook. What to do when a sync fails, how to replay a webhook, how to rotate secrets and how to upgrade the API version.
• For public apps: the App Store listing copy, screenshots, privacy policy inputs, billing plans set up through the Billing API, and the app registered in your own Partner organization.

A healthy app shows a low and falling error rate in monitoring, webhook deliveries processed without backlog, an API version that is still supported, and sync jobs that finish on a large catalog without hitting rate limits. For custom apps, the business measure is the manual work removed, which you track in staff hours or order handling time. For public apps, it is passing review and then install, uninstall and support ticket trends. We report on the technical measures; the commercial ones sit with you, and we do not promise app revenue or installs.

Technical Details That Decide Whether an App Holds Up

GraphQL first

Shopify has marked the REST Admin API as legacy and built its newer features on the GraphQL Admin API. We build on GraphQL so the app is not rewritten in two years, and we use bulk operations for large exports and imports instead of paging through thousands of single requests.

Rate limits and large catalogs

Shopify limits API usage by calculated query cost. An app that works on a test store with 50 products can stall on a live store with 40,000 variants. We design queries around cost, queue heavy jobs in the background and show merchants progress instead of timing out.

Customer data and permissions

Public apps that read protected customer data such as names, emails and addresses must request that access and meet Shopify's data protection requirements. We keep scopes narrow, store only what the app needs and document retention, which also shortens App Store review.

Shopify App Development Mistakes We Are Asked to Fix

Many of our app projects start as rescues of an app that worked in a demo and failed in production. The same problems come up again and again:

• Too many access scopes. Requesting write access to everything makes merchants hesitate at install and draws questions in App Store review.
• No protection against duplicate webhooks. Handlers that create a record every time a webhook arrives produce double orders or double stock adjustments when Shopify retries.
• Synchronous heavy work. Long imports run inside a web request, so they time out on big catalogs. Background queues and bulk operations fix this.
• A pinned, retired API version. The app keeps calling a version Shopify no longer supports, and features start failing without warning.
• Code injected into themes. Older apps wrote snippets straight into theme files. Theme app extensions replace that and leave no residue on uninstall.
• Building what Shopify Flow already does. Simple tagging, alerts and routing rules often need a Flow workflow, not an app.

Planning a Public Shopify App: Validation, Review and Built for Shopify

Founders selling on the Shopify App Store face questions a merchant building a custom app never has to answer. We work through them before the build starts.

Validate the idea first

Read the lowest reviews of App Store apps that already solve the problem, since they show what merchants still find missing. Then test a clickable Figma prototype with merchants who have the problem before committing to a full build.

Plan for App Store review

Public apps go through Shopify's review before they are listed. Reviewers check installation, billing through the Shopify Billing API, the mandatory privacy webhooks, listing accuracy and the embedded admin experience. We build to those requirements from the first sprint rather than retrofitting them.

Aim for Built for Shopify

Built for Shopify is a status Shopify awards to apps that meet its higher standards for performance, design and integration, and it earns extra visibility in the App Store. Using Polaris, App Bridge and theme app extensions from day one keeps that option open.

Custom Shopify App Development Use Cases by Business Type

• DTC brands. Post-purchase upsells on the thank you page, loyalty logic tied to order history, and product data sync from a PIM or spreadsheet that staff currently paste by hand.
• Brands selling wholesale. Order routing to a separate warehouse, net terms checks, and minimum order validation through Shopify Functions.
• Multi-location retailers. Stock reconciliation between POS locations and the online store, and click and collect rules that respect each store's opening hours.
• Brands with several sales channels. Inventory and order sync with marketplaces or an ERP, built on bulk operations so overnight jobs finish on time.
• Founders building a product. A public app that solves one clear merchant problem, launched with a narrow feature set and expanded from real merchant feedback.

Shopify App Development Stack

Why Choose 95 Solutions for Shopify App Development

• We run a Shopify-connected SaaS ourselves. AM Jarvis works with Shopify and WooCommerce stores daily, so API limits, product data quirks and merchant support are familiar problems.
• Senior-led scoping. Mustafa reviews every specification before a line of code is written, with 11+ years of digital marketing and a BS in Computer Science behind those decisions. That is rare at a larger Shopify app development agency, where scoping is often handed to a project manager.
• You own the code and the app listing. Repositories, hosting accounts and the Partner organization that owns a public app are registered to you.
• Clear commercial terms. Contracts and invoices come from our US LLC in USD, and the discovery sprint is credited against the build.

When to Hire a Shopify App Developer

A good fit

• Merchants whose team is copying data between Shopify and another system by hand every day.
• Stores that need discount, shipping or checkout rules the admin and existing apps cannot express.
• Founders with a validated app idea who want a senior team to build and launch the first version.

Probably not a fit

• A requirement an existing, well-maintained app already handles. We will point you to it instead.
• Theme-level changes such as a new section or layout. Those belong in Shopify theme development.
• Checkout step customizations on a non-Plus plan. Those need Shopify Plus first.

Shopify App Development Pricing

App projects start with a fixed-price discovery sprint that produces the specification and estimate, and its cost is credited to the build. The build itself is fixed price or split into phases, and ongoing upkeep can move onto a maintenance and support plan.

The main cost drivers are the number of admin screens, how many external systems the app talks to, the extension types involved (a single Function is far smaller than checkout, admin and theme extensions together), catalog and order volume, and whether the app is public, since billing, onboarding and review work add scope. Hosting is billed by the provider to your account.

To discuss an app idea or an integration you need, contact us with a short description and we will suggest the next step. Code and app listing ownership are covered in our agency FAQ.

Talk Through Your Shopify App Idea

Send us a few lines on the workflow you want to automate or the app you want to build, plus the systems it needs to touch. We reply within one business day, book a short call to ask the questions that decide the architecture, and then send a written proposal for the discovery sprint with its scope, timeline and fixed fee. If an existing app or Shopify Flow already covers the need, we will say so on that call. You can also call or WhatsApp us using the details on our contact page.