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Custom Shopify Apps & Checkout Functions

Shopify App Development Built Around The Logic No App Store Listing Can Handle

SkilledDesk builds custom Shopify apps — private apps wired into your store's own Admin API, embedded public apps built for App Store distribution, and checkout customizations rebuilt in Shopify's current Functions and Checkout UI Extensions model, not the checkout.liquid scripts Shopify already

retired.

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Checkout Function Executions
18,420
+34% MoM
Custom discount function calls, last 30 days
The Problem

What A Theme And An App Store Subscription Can't Cover

Checkout Customization That Broke When Shopify Retired The Old Model

Custom discount logic, shipping surcharges, or checkout upsells built through the old checkout.liquid template or Script Editor didn't survive Shopify's move to Checkout Extensibility — that functionality is gone outright until it's rebuilt in Shopify Functions and Checkout UI Extensions, a genuinely different programming model a theme edit can't touch.

Two Apps Racing To Write The Same Order Or Inventory Data

An inventory app and a wholesale-pricing app can both subscribe to the same webhook topic and fire their own update the moment an order comes in, with no guarantee which one runs last — the store ends up with whichever app happened to write second, not the correct combined result either app was actually built to produce.

Business Rules A Settings Toggle Was Never Built To Hold

Tiered wholesale pricing that changes by customer group and order volume, or fulfillment routing across more than one warehouse, is the kind of logic a generic App Store app only approximates with a fixed set of options — the moment the real rule falls outside those toggles, the app can't be configured around it, only worked around.

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Free Tool

How Solid Is Your Store's Technical Foundation, Right Now?

Before any custom app gets built on top of a store, the foundation underneath has to hold. Enter your store's URL for a free Store Tech Health Check. The scan looks at HTTPS, phone layout, speed and search readiness. Those are the same gaps a custom app inherits if nobody fixes them.

Takes about 5 seconds — no signup needed to see the score.

What We Build

What A Shopify App Build Covers

Custom Shopify App Development

Private apps wired directly into your store's Admin API for wholesale portals and ERP sync, embedded public apps built with App Bridge and Polaris, and checkout logic rebuilt in Shopify Functions — not a theme edit stretched past what Liquid can do.

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Paid social for an app launch

Product and app-feature content built for the platform your store's actual customers already scroll, tied to attribution that survives whatever your custom checkout build changes about how a purchase gets tracked.

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Search ads for merchant intent

Shopping and Search campaigns wired to server-side conversion tracking, built to keep reporting accurate through a custom checkout rebuild instead of quietly losing purchase events the moment old Liquid-based tracking scripts stop running.

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The Numbers Behind Every Shopify App We Ship

130+
Brands Served
14+
Countries Reached
2019
Founded In Wyoming, USA
1:1
Direct Founder Access

What Does Shopify App Development Actually Cover?

Shopify app development means writing software that runs inside or alongside a store's own Admin API and checkout pipeline. SkilledDesk handles Shopify app development where checkout logic is rebuilt properly rather than patched around a deprecated tool. Not customising a theme. Not installing something ready-made from the App Store. A private app might sync inventory and order data with an existing ERP, or run a wholesale pricing engine unique to one merchant. A public app gets built for App Bridge and Polaris, so it embeds inside the Shopify Admin the way Shopify's own screens do. It then goes through Shopify's review before listing.

Shopify retired checkout.liquid and the Script Editor in favour of Checkout Extensibility. So any checkout-level customisation, a discount rule, a shipping surcharge, a post-purchase upsell, has to arrive as a Shopify Function or a Checkout UI Extension. That is a genuinely different API surface from the Liquid templating most Shopify web design work is built around. SkilledDesk builds exactly this layer for Shopify brands. Private and public apps written against the current GraphQL Admin API, since the REST Admin API is Shopify's legacy surface now, plus the Functions and Extensions work checkout customisation requires. That aims at Shopify specifically, and it sits apart from the custom application developmentwork that focuses on a store's theme or product pages.

Why Not Just Install An App From The Shopify App Store Instead?

A ready-made app is genuinely the right call for anything close to a standard use case. Reviews, basic email flows, a simple loyalty program. It stops working the moment a business rule falls outside whatever settings toggles that app's developer chose to expose, with no way past that UI to adjust the underlying logic. The usual workaround stacks another app on top. Often a middleware layer that has to sit outside Shopify entirely, polling for webhook events and calling back into the store's API on its own schedule. That adds a whole extra system, one that can lag, fail silently, or drift out of sync with what Shopify's own data shows. A Shopify Function runs natively inside Shopify's own checkout and discount pipeline instead. No external service watching for events. No polling delay. Just the business rule executing exactly where Shopify already executes everything else. It gets built once and owned outright. The founder writes the integration code directly, rather than hand the API work to a subcontractor. Real Shopify builds sit open on the portfolio to check first.

A Shopify Build Already On The Portfolio

No custom app has its own named case study yet, because an app build takes longer to produce a shareable number. A store launch inside that history closed at $21K.
See Our Full Portfolio
FAQ

Straight Answers To The Questions A Custom Shopify App Raises

The number moves with how much of the store's data your app touches, and how it gets distributed. Not catalogue size. A private app for one store, syncing inventory to a single ERP or running one custom pricing engine, typically runs $4,000 to $12,000. That depends on how many Admin API resources and webhooks it needs. A public, embeddable app built for App Store distribution, with its own Admin UI extensions and multi-store support, usually runs $15,000 to $40,000-plus once Shopify's technical review requirements are factored in. We confirm scope on the free call before quoting anything. App work with us opens at $1,199, and a private app syncing to an ERP is scoped by integration rather than by a flat build price.
A single-integration private app typically takes three to five weeks. One ERP connection, one pricing engine, one Function. A multi-integration build or a public app runs six to twelve weeks for the development itself. If it goes to the App Store, add Shopify's own review cycle. Their team audits the app against a specific technical and UX checklist, and can come back with revision requests before approval. That timeline sits with Shopify, not with us, and we flag the possibility on day one rather than let it surprise you in week eight.
A redesign changes what the store looks like, and how a product page or checkout flow presents to a shopper. That is theme and Liquid work, the same territory a Shopify web design project covers. An app changes what the store can do. Syncing data with another system, running business logic no theme setting can hold, or customising checkout beyond what Checkout UI Extensions expose out of the box. The two get built together often enough. They are still genuinely different disciplines, one changing the interface and the other changing the machinery underneath.
Both, and the two are genuinely different projects. A private app gets built and installed on one store only. No Shopify review, faster to ship, and it can carry business logic specific to that one merchant. A public app has to work cleanly across different stores' data, meet Shopify's Built for Shopify technical and performance requirements, and pass Shopify's own review before listing. Which one makes sense depends on whether the goal is solving one store's problem or eventually distributing the same solution to other merchants.
Yes, but not as a like-for-like copy. Script Editor and checkout.liquid no longer exist. So whatever logic used to live there gets rewritten as a Shopify Function, for discounts, shipping and payment customisation, or a Checkout UI Extension for anything shown on the checkout page. The underlying business rule usually survives the rebuild fully intact. It is the code around it that has to change to Shopify's current model.
That is one of the most common private-app builds. A two-way sync pulls stock levels and order status from your ERP or warehouse system into Shopify, and pushes new orders back out. Nobody re-enters the same data twice, and nobody trusts a number that has already gone stale by the time someone checks it. The exact integration points depend on what system you already run, which we map out before any code gets written.
Plenty of agencies that built a name on Shopify theme and Liquid work never picked up Shopify's current Functions and GraphQL Admin API model. So when a merchant's old checkout.liquid customisation broke, that same shop often cannot rebuild it in the model Shopify supports now. The founder handles the API and Functions work directly here, without handing the integration piece to a subcontractor, with real Shopify builds already open on the portfolio before you commit.

Ready To Build The Piece A Theme Or App Store Listing Can't?

Bring the business logic you actually need. A wholesale rule, an ERP sync, a checkout customisation that broke. You leave the call with a real scope and quote, not a guess.

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