Custom development · private apps, integrations, Functions
Shopify app development agency for what the theme cannot do.
Most stores run on apps until one becomes the constraint — the integration that half works, the checkout rule the platform will not express, the process a team still does by hand. That is the work we take.
Book a callDescribe the problem
- and custom apps
- Private
- Integrations
- ERP, PIM, 3PL
- Functions & checkout
- Plus
- The code
- Yours
Why custom
Why Shopify stores commission a custom app.
Usually one of these six, and often two at once. The first conversation is about which one it is.
- 01
A manual job that eats a day a week
Orders re-keyed into the ERP, stock counts pasted between tabs, refunds approved by email. If someone does it on a schedule, software usually can.
- 02
Three apps doing one job badly
Several subscriptions and scripts stitched together to approximate one workflow. A single purpose-built app often replaces them, and their monthly fees.
- 03
Checkout rules the admin cannot hold
Shipping tiers by customer type, payment methods hidden for certain baskets, discounts that must stack in a set order. Functions exist for exactly this.
- 04
Data that must not sit in a theme
Credentials, pricing rules or customer records that should never live in theme code need a secure home that the storefront calls.
- 05
A feature that must outlive the theme
Logic written into a theme disappears at the next redesign. Kept in an app, it stays put whichever theme is live.
- 06
An app nobody can maintain
Built by a freelancer who moved on, undocumented, pinned to an old API version. It deserves a careful read before anyone decides to rebuild it.
What we build
Four kinds of Shopify app work we take on.
We are also building our own Shopify apps, with the same team, so lessons from product work carry straight into client builds.
- 01
Private and custom apps
An app built for your store and nobody else: admin tooling, a merchandising surface your team will actually use, or a customer-facing feature the theme cannot carry.
- 02
Integrations and middleware
ERP, PIM, 3PL, subscriptions, loyalty and tax. Built to survive the other system being slow, wrong or briefly offline, because eventually it will be.
- 03
Checkout, Functions and Plus extensibility
Discount, delivery and payment customisations written as Functions and checkout extensions — supported surfaces, not scripts that break at the next upgrade.
- 04
Headless and storefront APIs
Hydrogen and Storefront API builds where the requirement genuinely needs them. We will tell you when it does not.
The stack
The Shopify app stack we build on.
Shopify’s own framework and APIs, so nothing depends on a workaround the next platform release can break.
ShopifyApp extensions and the admin
GraphQLAdmin and Storefront APIs
ReactEmbedded admin interfaces
Remix / React RouterShopify’s app template
TypeScriptTyped integrations- Shopify FunctionsDiscount, delivery and payment logic
How it runs
How a custom Shopify app project runs.
Scoped, fixed, and yours at the end.
- Step 1
Describe the problem
Not the feature you think you need — the thing that is not working. Most briefs shrink once the constraint is named.
a form or 30 minutes - Step 2
A technical read
What is possible on the supported surfaces, what needs a workaround, and where Shopify will fight you.
in writing - Step 3
Fixed scope
A price against a defined build. Changes are re-quoted rather than absorbed into a retainer that never ends.
agreed before we start - Step 4
Shipped and handed over
The code is yours, documented, in your repository. No lock-in.
your repo, your account
What you get
What a custom Shopify build hands over.
- A technical read
- In writing, before any price: what the supported surfaces allow and where a workaround would be needed.
- A fixed scope
- One price for a defined build. Anything new is quoted separately rather than absorbed quietly.
- Your repository
- Source code and documentation in your own account from the first commit, not handed over at the end.
- A runbook
- How it is deployed, which API versions it depends on and what to check when something upstream changes.
Custom build questions
What people ask before they brief.
What counts as a custom Shopify app?
Functionality built for one merchant rather than for the app store: admin tooling, a customer-facing feature the theme cannot carry, or logic that must run server-side. Shopify documents the app build surfaces these use.
How is a custom app different from an app store app?
A public app serves thousands of stores and is shaped by that. A custom app serves yours, does exactly what you need, carries no upgrade path you did not choose, and has no monthly fee attached to features you never use.
Should this be an app or a theme change?
Usually the theme, and we will say so. An app is right when the logic must survive a theme change, run server-side, hold credentials, or touch checkout.
Do we own the code?
Yes. It ships to your repository and runs in your Shopify Partner or hosting account. You are not renting access to your own build.
Can you integrate Shopify with our ERP or PIM?
Yes — ERP, PIM, 3PL, subscriptions, loyalty and tax. The engineering that matters is what happens when the other system is slow, wrong or briefly offline, because eventually it will be.
Can you customise Shopify checkout?
On Plus, yes, through checkout UI extensions and Shopify Functions for discount, delivery and payment logic. These are supported surfaces, unlike the old checkout scripts that break at upgrade.
What does a custom Shopify app cost?
It is quoted against a defined build after a technical read, not estimated from a feature list. Most briefs shrink once the actual constraint is named, which is why the read comes before the number.
Can you work with our in-house developers?
Yes. A lot of this work is one specific piece alongside an existing team rather than instead of one.
Do you build headless or Hydrogen storefronts?
Where the requirement genuinely needs them. We will also tell you when it does not — headless is a bill, not a strategy, and most stores that want it need speed and structure work instead.
Can you fix or take over an existing app?
Often, yes. We read what is there first and say plainly whether it is worth repairing or replacing, rather than defaulting to a rebuild because a rebuild is easier to quote.
Do you publish your own Shopify apps?
We are building our own now. Client builds and our own products are written by one team to one standard, so patterns proven in product go into client work.
What happens after it ships?
It is documented and handed over, in your repository and your account. No lock-in and no dependency on us to keep it running, though we are available if you want us.
Book 30 minutes
Tell us what is not working.
A form or thirty minutes. You get a technical read either way, not a proposal deck.