Shopify Public App Development
A public app is a product, not a project. It has to install cleanly for merchants you'll never speak to, bill them reliably, survive Shopify's review process, and keep working through quarterly API versions for years. We build public apps with that whole lifecycle in mind — OAuth, Billing API, mandatory webhooks, listing submission and the versioning discipline that comes after.
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Why it matters
The code is the easy part. Everything around it is what fails review.
Most first-time public apps are rejected for the same handful of reasons: the OAuth flow mishandles scopes or reinstalls, the mandatory GDPR webhooks aren't implemented, billing doesn't use the Billing API, or the listing makes claims the app doesn't deliver. None of that is about your core feature — it's about the platform contract every listed app has to honour. We build against that contract from the first commit rather than retrofitting it after a rejection. The other half of the job is what happens after approval: multi-tenant data isolation, uninstall handling, support load, and a release process that doesn't break stores when you ship.
Sound familiar?
Public apps are usually pitched from one of these positions.
A couple of these are strong commercial starting points. The rest tend to underestimate what a listed app costs after launch.
- You built something for your own store and merchants keep asking whether they can buy it.
- You've found a category on the App Store where every option has poor reviews.
- Your SaaS product already serves ecommerce merchants and Shopify is the obvious next channel.
- You think listing on the App Store is a distribution channel that markets itself.
- An agency built you a custom app and now you want to sell it to others.
- You need recurring revenue and an app feels cheaper to launch than a full product.
What's included
What a public app build includes
Everything Shopify requires of a listed app, plus the architecture that keeps it stable as install numbers grow.
OAuth and session management
The full install flow done to spec — authorisation, HMAC verification, offline and online access tokens, scope changes handled without forcing reinstalls. We test the awkward paths too: reinstalls, uninstall-then-reinstall, and shops that revoke access mid-session.
Billing API and pricing plans
Recurring charges, usage-based charges, trial periods and plan upgrades through Shopify's Billing API, so merchants pay on their Shopify invoice. Charging outside the Billing API for anything Shopify considers in-scope is a reliable way to fail review or get delisted later.
Webhooks and GDPR compliance
The three mandatory privacy webhooks — customer data request, customer redact, shop redact — implemented and verifiably responding, plus the business webhooks your app needs. HMAC verified, idempotent, and queued so Shopify's retries never create duplicate work.
Multi-tenant architecture
One codebase serving every install, with strict per-shop data isolation, per-shop rate-limit budgets and background jobs that don't let one large merchant starve the rest. This is the part that quietly decides whether the app survives its first thousand installs.
Listing and review submission
App listing copy, screenshots, demo store, privacy policy and the review questionnaire prepared together, then submitted and shepherded through Shopify's feedback rounds. Rejections are normal on first submission; we handle the responses and the resubmission.
Versioning and ongoing support
Quarterly Shopify API version upgrades, deprecation monitoring, error tracking across all installs, and a release process with staged rollout. Plus the support tooling — logs searchable by shop domain — that turns a merchant ticket into a five-minute answer.
How it runs
How a public app build actually runs.
Roughly 10–16 weeks to a submitted listing, plus one to four weeks in Shopify's review queue depending on how much feedback comes back.
- 01
Scope the first version
We cut the feature list to what a merchant would pay for on day one. Public apps fail more often from a bloated v1 that ships late than from a narrow one that ships and learns.
- 02
Build the platform layer
OAuth, billing, webhooks, tenancy and the admin shell first, before feature work. These are the pieces review actually tests, and retrofitting them into a finished app is consistently more expensive.
- 03
Build and dogfood
Feature development on development stores, then installed on a real store — often yours — under real conditions. Merchant-facing copy, empty states and error messages get written now, not at submission.
- 04
Submit and iterate
Listing assets prepared, app submitted, and every round of Shopify feedback answered until approval. Then staged rollout with error tracking so the first real installs are watched closely.
OAuth
Install flow
Scopes, reinstalls, revokes
Billing API
Merchant billing
Recurring & usage-based
3
GDPR webhooks
Mandatory for every listing
Quarterly
API versions
Upgrades tracked, not ignored
Straight answer
Building the app is maybe half the total cost. Be sure about the other half.
A good fit if…
- You have a clear commercial thesis — who pays, how much, and why they'd switch from what exists.
- You've budgeted for support, maintenance and API version upgrades, not just the initial build.
- You can validate demand first, ideally from merchants already asking you for this.
- You want long-term ownership of a product, with someone internally accountable for it.
Probably not, if…
- You only need this for your own store. A custom app costs far less and skips review entirely.
- You expect App Store listing alone to generate installs. It won't without marketing.
- Nobody will own support after launch, so merchant tickets will go unanswered and reviews will suffer.
- The budget covers the build but nothing beyond it — an unmaintained app breaks within a year.
Keep exploring
More on Shopify app development
Public App Development is one part of how we build Shopify apps. Here's the rest of the picture.
Shopify App Development
The complete service — custom apps, extensions and Functions, in one engagement.
View the serviceClosely relatedEmbedded Admin Apps
The interface layer every public app needs — App Bridge, Polaris and session tokens.
Read the guideClosely relatedCustom App Development
If it's only for your store, skip the listing and the review process entirely.
Read the guideAll guides in this series
- Theme App ExtensionsApp blocks merchants drop into any OS 2.0 theme — no code edits, no forked themes.
- Checkout UI ExtensionsUpsells, custom fields and trust content inside Shopify's own checkout.
- Customer Account ExtensionsOrder tracking, subscriptions and self-service inside new customer accounts.
- POS UI ExtensionsIn-store workflows on Shopify POS — custom tiles, actions and staff tooling.
- Shopify Functions DevelopmentBackend cart, discount and delivery logic running on Shopify's own infrastructure.
Beyond this service
Other things we do
Most stores need two or three of these working together. Book a call and we'll tell you which ones actually move your numbers.
- Shopify Theme DevelopmentCustom themes built from Figma to production Liquid on Online Store 2.0 — fast and merchant-editable.
- Shopify App DevelopmentCustom and public apps, Checkout UI Extensions and Shopify Functions built with React and Polaris.
- Shopify MigrationMove from WooCommerce, Magento or BigCommerce with a full 301 redirect map and zero downtime.
- Shopify SEOTechnical audits, Core Web Vitals, structured data and collection content built around buyer intent.
- Shopify Performance OptimizationFaster load times and green Core Web Vitals — theme refactors, image pipelines and app cleanup.
- Shopify A/B TestingHypothesis-led experiments on product pages and checkout, shipped as native theme code.
- Shopify Email Marketing & KlaviyoFlows, segmentation and campaigns — welcome, abandoned cart, winback and SMS, built and monitored.
- Shopify CRO & FunnelsValue-ladder, tripwire, quiz and post-purchase upsell funnels built to lift conversion and AOV.
- Shopify Maintenance & SupportRetainers covering uptime monitoring, security patching, bug fixes and proactive improvements.
Frequently asked questions
- Usually one to four weeks, and first submissions frequently come back with feedback rather than approval. The common causes are OAuth or billing implementation issues, missing mandatory privacy webhooks, listing copy that overstates what the app does, or a demo store the reviewer can't properly test. We prepare for review from the start and handle the feedback rounds, but nobody can promise a first-pass approval.
Thinking about listing an app?
Book a 30-minute technical call. We'll pressure-test the commercial case and the scope before you spend anything on a build.
Book a free call