Custom app or App Store app: build or install?

The Shopify App Store is the right answer more often than a studio that builds apps would like to admit. A listed app has been through Shopify’s review, gets updated by its developer and usually costs a monthly fee instead of a project budget. A custom app earns its cost in a narrower set of cases, and it is worth knowing which case you are in before you ask anyone for a quote.

What “custom app” means on Shopify today

Shopify has two ways to distribute an app, and the choice can’t be changed after it is made:

One change catches merchants who remember the old way: custom apps can no longer be created directly in the Shopify admin. A new custom app is built as a Shopify app and given custom distribution. Apps created in the admin earlier keep working, but their distribution method can’t be changed.

When installing is the better answer

• The job is common. Reviews, subscriptions, loyalty, email capture, product feeds: many stores need the same thing, and a maintained app will keep up with Shopify’s changes for you.
• Your process can bend. If adjusting how the team works to fit a good app costs less than a build, adjust.
• You are not on Plus and the logic lives in checkout. Discounts, delivery and payment rules, and checkout validation are built as Shopify Functions. On plans other than Plus, a Function can reach your store only inside an App Store app, because custom apps containing Functions need Shopify Plus.
• Nobody will own it. A custom app is software your business owns. If no one will maintain it, a maintained App Store app is safer.

When a custom app earns its cost

• The workflow is yours alone. A pricing rule, a production step, an approval chain or a data model that no general app is designed for. Stacking three apps that each cover a third of it is usually the sign.
• It connects to a system only you have. An ERP, a warehouse system or an internal tool. Integrations are specific by nature; see what planning an inventory sync involves.
• The data shouldn’t leave your control. A custom app is installed only on your store, and you decide where its data lives and who can reach it.
• An app you rely on is being retired. When a tool your operations depend on shuts down, a custom replacement can keep the workflow exactly as it was instead of forcing a new process.
• Checkout logic specific to your store, on Plus. A Plus store can run its own Functions in a custom app: validation rules, delivery rules, discounts or bundles no listed app models.

The costs people forget

The build is the visible cost. The ones that matter over three years are quieter:

• API versions. Shopify releases a new API version every three months. Each stable version is supported for at least 12 months, with at least nine months of overlap between consecutive versions. A custom app has to be moved to newer versions on that schedule, which is small, regular work, not a one-off.
• Hosting and monitoring. A custom app runs somewhere: a server, a database, background jobs, error alerts. Someone pays for it and someone watches it.
• Knowledge. If one developer holds the whole design in their head, the app is fragile. Ask for the code in your own repository and written notes on how it is deployed.
• No App Store safety net. Custom apps skip Shopify’s app review. That removes a step, but it also means the quality bar is the one you and your developer set.

The App Store has costs too: monthly fees that add up across apps, features you pay for and don’t use, and the risk that an app changes its pricing or is discontinued. Compare the two over the same period, not a build quote against one month’s fee.

A checklist before deciding

1. Write the workflow down: who uses it, what goes in, what should come out, and how often.
2. Search the App Store for it, and trial the two or three closest apps against that written workflow, not against a demo.
3. List what is left over. If it is small, install and adapt. If it is the core of the job, a build is worth pricing.
4. Check the plan. If the logic belongs in checkout and the store isn’t on Plus, a custom app with Functions is not available.
5. Price both routes over the same period, including maintenance, hosting and API version upgrades on the custom side.
6. Decide who owns the custom app after launch: the code, the hosting account and the Shopify app configuration should all be in the store’s name.

Questions to ask before a custom build

If the checklist points to a build, these questions separate a custom app you can live with from one that becomes a problem in a year. They apply to any developer, including us.

• Whose Shopify account holds the app? The app’s configuration, its client credentials and the distribution setting should be under an account the business controls, not only the developer’s.
• Where does it run, and who pays for that? Ask for the hosting provider, the expected monthly cost and who receives error alerts.
• Which API version does it target, and who upgrades it? With a new version every quarter, upgrades should be part of the maintenance agreement, not a surprise.
• What data does it store outside Shopify? Customer and order data held elsewhere is your responsibility too. Ask what is stored, where and for how long.
• What happens if it stops working? A custom app that touches checkout or inventory needs a documented fallback, even if that is a manual process for a day.
• Can another developer take it over? The test is simple: is there a repository and a short document someone new could deploy from?

An App Store app answers most of these for you, which is part of what its monthly fee pays for. A custom app should answer them in writing before the build starts.

Where Lintel fits

Lintel builds custom Shopify apps for workflows the App Store doesn’t cover, and Functions inside them when checkout logic is part of the job, through its Shopify Functions work. The public-app side is checkable: Lintel’s founder built three apps listed on the Shopify App Store (BlogPilot AI, AgentRank and Stockcast), each of which went through Shopify’s app review. Stockcast, for example, was built to replace Shopify’s Stocky app, including import of Stocky purchase-order CSVs. The first conversation starts from the checklist above, and it can end with “install this app instead”.