We build custom Shopify apps for merchants who have run out of App Store options — ERP middleware, bundle builders, POS extensions, checkout logic on Shopify Functions. Five of them are named on this page, including a bundle builder running across every market Medik8 sells in.
Shopify Scripts were fully deprecated on 30 June 2026 and no longer execute. Editing and publishing new Scripts ended on 15 April 2026. Any discount, shipping or payment customization that lived in the Script Editor has stopped working, and the replacement is Shopify Functions — which requires an app, not a script.
If you were a Shopify Plus merchant using Script Editor for volume discounts, tiered pricing, custom shipping rules or payment method logic, that logic is already gone rather than going. It did not fail loudly. It simply stopped applying, which means the symptom is usually a margin problem someone notices in a report weeks later, not an error page.
Rebuilding on Shopify Functions is not a port. Functions run on Shopify's own infrastructure, written in Rust or in JavaScript compiled through Javy, and they are delivered inside an app. That is the most common reason a merchant needs custom app development in 2026 without having planned for it.
Shopify app development covers building software that extends Shopify through its APIs and extension points. Those extension points are Shopify Functions for back-end logic such as discounts and shipping, checkout UI extensions, theme app extensions for storefront components, admin extensions, POS UI extensions, and app proxy. Apps are either custom, built for a single merchant, or public, distributed through the Shopify App Store.
The terminology has shifted twice and still confuses people. Private apps were deprecated in January 2022 and auto-converted to custom apps in January 2023. Custom apps remain very much alive — what changed on 1 January 2026 is only where you create them.
| Custom app | Public app | |
|---|---|---|
| Built for | One merchant or organisation | Many merchants |
| Distribution | Installed directly, no App Store | Shopify App Store listing |
| Shopify review | None | Required — commonly 2 to 6 weeks |
| App Store registration | Not required | $19 one-time per Partner account |
| Revenue share to Shopify | None | 0% on first $1M lifetime, then 15% |
| Ongoing obligation | API version upgrades | API upgrades, support, billing, onboarding |
| Right when | Solving your own operational problem | Building a product for a market |
Nearly every merchant reading this page needs a custom app. Public apps are a product business with a support function attached, and the economics are covered further down for anyone weighing that instead.
We build apps for a living, so treat this section as written against our own interest. Four situations where building is the wrong answer:
Take the 80%. A custom app carries permanent maintenance — quarterly API versions, dependency upgrades, breakage when Shopify deprecates something. An imperfect app someone else maintains is usually cheaper over three years than a perfect one you own.
At that stage the annual maintenance cost of a custom app is disproportionate to the benefit. Spend the money on traffic and conversion instead.
Some apps get commissioned to automate a workflow that should not exist. We would rather point that out in scoping than build the automation and invoice you for it.
An app with no owner becomes an outage waiting for a Shopify API deprecation. If there is no maintenance budget, there should be no app.
The honest version of the test is this: build when the functionality is genuinely specific to how your business operates, when it protects margin or removes recurring manual work, and when somebody will own it. Otherwise install something.
Event-driven synchronisation between Shopify and the systems your operation actually runs on, using Admin APIs and webhooks rather than stacked connector apps. Fewer failure points, and rate limits you control.
Discount logic, shipping rules, payment customisation and cart transforms running on Shopify's infrastructure. This is where Script Editor logic now lives, and it is the most common request we receive.
Medik8's bundle builder is a reusable app running across every market they sell in, rather than a separate build per region.
Contract pricing, approval workflows and automated ordering rules that native B2B does not cover. Elm Biosciences runs automated ordering rules for a dermatologist network.
The Los Angeles Apparel flagship runs staff-specific POS tiles built for how that shop floor actually operates.
For HUK Gear we built custom discount logic spanning multiple sales channels, plus the apps keeping inventory synced across 59 POS locations.
Aspen Publishing delivers e-books to college students through a backend managing timed access to digital content.
Custom blocks and actions on product, order and customer pages, so your team works inside Shopify admin instead of alongside it in a spreadsheet.
| Extension point | What it does |
|---|---|
| Shopify Functions | Back-end logic on Shopify's infrastructure — discounts, shipping, payment, cart transforms |
| Checkout UI extensions | Adds interface to checkout without touching checkout code |
| Theme app extensions | Storefront components installed into a theme, replacing script tags |
| Admin extensions | Custom blocks and actions inside Shopify admin |
| POS UI extensions | Custom tiles and workflows on the point of sale |
| Admin API and webhooks | Reading and writing store data; event-driven integration |
| Customer account extensions | Custom functionality in the logged-in account area |
| App proxy | Serving your own authenticated pages under the store domain |
Most agency app pages describe outcomes. These are our actual engineering standards, so you can compare them against anyone else you are evaluating.
Our current standard for new Shopify app builds. We still maintain Remix apps and older Express builds, but new work starts on React Router 7.
Admin interfaces built in Polaris so your team gets Shopify's own interface conventions rather than a bolted-on panel that behaves differently.
Correct OAuth flow and durable session storage from the first commit. This is where cheap app builds fail first, and the failure surfaces as merchants being logged out or scopes silently breaking.
Every webhook verified. Unverified webhook endpoints are an open door, and they are common.
Shopify's required data-request, customer-redact and shop-redact topics handled, not stubbed.
Shopify ships quarterly API versions and deprecates on a schedule. We keep client apps on supported versions as part of maintenance rather than discovering a breakage after it happens.
All work in version control with reviewed, reversible changes. No editing production directly.
We are happy to answer all five on a call. Any agency that cannot is likely to hand you an app that works on launch day and breaks two API versions later.
Shopify's revenue share is 0% on your first $1,000,000 USD of lifetime gross app revenue earned from 1 January 2025, then 15% above that, plus a 2.9% billing processing fee. App Store distribution requires a one-time $19 registration per Partner account. Registration is not required for custom apps built for a single merchant.
Two details matter more than the headline rate. The $1M exemption became a lifetime threshold in January 2025 rather than resetting annually, so model 15% as your steady-state platform cost once you succeed. And Shopify announced further changes to its partner earnings model on 7 July 2026 — check the current terms in the Partner Dashboard before building a business case on any figure, including these.
The harder truth is distribution. The App Store holds well over ten thousand apps and the revenue distribution is severely power-law: a small top tier clears meaningful revenue and the median listed app earns very little. Monthly churn commonly runs from around 5% for apps embedded in critical workflows to double digits for easily replaceable tools. A public app is a product company with a support desk, not a build.
Our honest advice to merchants: build the custom app that solves your problem. If it turns out to generalise, that is a product decision to make later with real usage data behind it, not an assumption to fund up front.
Custom Shopify app projects at Solo Media Group start at around $20,000, quoted as a line-item estimate, with typical builds running 4 to 10 weeks. Industry benchmarks put custom app builds broadly in the $15,000 to $80,000 range. Budget for maintenance as well as build — quarterly API versions and dependency upgrades are ongoing, not optional.
That last one is the biggest and least expected variable. Undocumented business logic is the most common cause of app scope expanding mid-build, because rules that live only in someone's head have to be discovered before they can be coded. Retainers start at 20 hours or $3,000 per month, and our Shopify Plus cost guide covers budgeting across build types.
Beauty · Multi-market bundle builder
Beauty · Multi-market bundle builder
Outdoor apparel · Inventory sync, cross-channel discounts
Outdoor apparel · Inventory sync, cross-channel discounts
Life sciences · Automated ordering rules
Life sciences · Automated ordering rules
Education · Timed content access
Education · Timed content access
Education · Timed content access
Education · Timed content access
Custom app development is a listed capability on our Shopify Partner Directory profile. As a Platinum-tier Shopify app development agency we are rated 5.0 from 37 reviews, and both the tier and the capability are verifiable on Shopify's own site rather than only on ours.
Shopify ships quarterly API versions and deprecates on schedule. An app built once and never touched will break — the only question is which quarter. Maintenance belongs in the original business case.
Rules that exist only in a colleague's head get discovered during the build, at build rates. A day spent writing the rules down before scoping is the cheapest day in the project.
Sometimes the honest answer is a $29 per month App Store app. Ask any developer to justify building rather than installing, and be suspicious if they never suggest installing.
Cheap builds cut corners on session storage and webhook verification. The consequences arrive later as mystery logouts, silently missed events and a security exposure nobody is looking for.
Script Editor logic does not translate line by line to Shopify Functions. The execution model is different and the rebuild needs testing against real orders, not a code review.
No. Editing and publishing new Scripts ended 15 April 2026, and all Shopify Scripts ceased executing on 30 June 2026. Discount, shipping and payment logic that lived in the Script Editor has stopped applying. The replacement is Shopify Functions, which are delivered inside an app.
A custom app is built for one merchant and installed directly, with no Shopify review and no revenue share. A public app is listed on the Shopify App Store, requires review — commonly 2 to 6 weeks — and carries revenue share above $1M in lifetime earnings. Most merchants need a custom app.
No. Private apps were deprecated in January 2022 and existing ones auto-converted to custom apps in January 2023. Store-specific apps are still entirely viable — they are just called custom apps, and since 1 January 2026 they are created through the Shopify Dev Dashboard rather than the store admin.
Our projects start at around $20,000, quoted as a line-item estimate. Industry benchmarks put custom builds broadly between $15,000 and $80,000 depending on integration count and complexity. Budget maintenance separately — quarterly API versions are ongoing.
Four to ten weeks for a typical custom app, from scoping to production. The largest variables are how many external systems are involved and how well your business logic is documented before we start.
You keep 100% of your first $1,000,000 USD in lifetime gross app revenue earned from 1 January 2025, and 85% above that, plus a 2.9% billing processing fee. App Store distribution requires a one-time $19 registration. None of this applies to custom apps built for a single merchant.
Custom apps work across paid plans. Some extension points, including aspects of checkout extensibility, are Plus-only. We confirm what your specific requirement needs during scoping rather than assuming an upgrade.
Yes, and we do it regularly. We audit the OAuth flow, session storage, webhook verification and API version first, then give you an honest assessment of whether it should be maintained or rebuilt.
Done properly it usually speeds it up. A single purpose-built app frequently replaces several App Store apps, each injecting its own scripts and storefront assets. Consolidating that payload is a common side benefit.
API version upgrades on Shopify's quarterly cycle, dependency updates, monitoring, and fixes when Shopify deprecates something an app depends on. Our retainers start at 20 hours or $3,000 per month.
We focus on custom apps for merchants. A public app is a product business with onboarding, billing and support obligations attached, and we will tell you honestly if that is outside what we should take on for you.
Install if an App Store app gets you to roughly 80%. Build when the functionality is specific to how your business operates, protects margin or removes recurring manual work, and somebody will own it afterwards. We will say which we think applies on the call.
