This article looks at the use cases for Shopify Apps and custom code, and introduces the process our Shopify agency uses to decide which is right for a given task.
Shopify makes it easy to add features. That’s one of its superpowers. Need reviews? Add an app. Need subscriptions? Add an app. Need upsells, gifting, personalisation, advanced search, loyalty, bundling? There is an app for nearly everything.
The problem is that “easy to add” is not always the same as “a good idea”. Over time, many Shopify stores drift into app overload, which inevitably means performance slips, messier admin and creeping cost increases. When something breaks, it is hard to know where to look, and merchants end up paying for functionality twice, or carrying tools that no one even uses anymore.
So how do you decide whether to use an app or build something custom? This is one of the most important judgement calls a Shopify agency makes, because it affects speed, stability, cost, and your ability to iterate.
Here is the framework we use.
Shopify app process step one: define the job, not the tool
Before deciding “app or custom”, clarify what the feature needs to do in business terms. It’s surprisingly common for a merchant to request “a loyalty app” when the actual goal is “increase repeat purchases” or “improve perceived value”. The right solution might be loyalty points, but it might also be a simpler set of incentives, better email automation, or a more effective post-purchase experience.
When the job is clear, the solution becomes easier to judge. Tools should serve the goal, not become the goal.
Shopify app process step two: is the feature a commodity or a differentiator?
Some features are best bought because they are not your competitive advantage. Reviews, subscriptions, search, email capture, and referrals are often better handled by specialist vendors who maintain their products constantly. Building these from scratch rarely makes sense unless you have very unusual requirements.
Other features can be differentiators. If you sell products that require bespoke configuration, complex bundling logic, or a unique customer journey, custom development can create a real advantage. In those cases, an off-the-shelf app may be a compromise that limits what you can do.
This is where a Shopify agency’s experience matters: they know which categories of apps are reliable, which are heavy, and where custom code tends to deliver a better outcome.
Shopify app process step three: what is the performance cost?
Performance is often the hidden factor. Many apps inject scripts into the theme, sometimes on every page. One app is rarely the issue, it’s accumulation that causes problems.
When we evaluate apps, we think about whether the script load is justified by the value. We also look at whether the app can be implemented in a lightweight way, such as through app embeds that can be controlled more cleanly, or by limiting where scripts load.
If the store is already heavy, adding one more app might be the tipping point. In that scenario, custom code can sometimes be the lighter choice, especially for simple features that do not need a full external platform behind them.
Shopify app process step four: what is the real cost over time?
Apps feel cheap upfront because they are subscription-based. But subscription costs add up, especially over years. A £30/month app is over £1,000 across three years, and many Shopify stores run far more than one.
Custom development has a higher upfront cost, but it can be cheaper long-term for stable features. It can also reduce operational complexity, because the feature becomes part of the theme or part of a bespoke app you control, rather than a third-party dependency.
The right question is not “which is cheaper today?” but “which is cheaper and safer across the lifespan of my store?”
Shopify app process step five: what happens if the app changes, breaks, or disappears?
Third-party risk is real.
- App updates
- Pricing changes
- Features being removed
- Vendor acquisition
- Withdrawal of product support
If a core store function is dependent on an app and that app changes, you can be forced into urgent, unplanned work.
That does not mean “never use apps”. It means you should be deliberate about which features become dependent on third parties. If something is mission-critical, you want a plan. That might mean choosing a mature vendor, ensuring data portability, or building a fallback option.
Shopify app process step six: can you maintain the custom solution?
Custom code is not without risks. If it is built poorly, undocumented, or overly complex, it can become harder to maintain than an app.
The goal of custom development should be maintainability and performance. That means clean architecture, documentation, and a sensible approach to future changes. It also means using Shopify’s supported tools where possible, rather than hacks that will break.
A Shopify agency should be able to explain how the custom solution will be maintained, where it will live (theme code, Shopify Functions, a custom app), and what the operational implications are.
Putting it all together: examples of good Shopify development decisions
In practice, a store might choose apps for complex systems like subscriptions or reviews, because those systems require infrastructure and ongoing updates. The same store might choose custom code for a lightweight feature such as a bespoke size guide module, a custom product badge system, or a specialised content component that would otherwise require a bloated page builder.
Often the best solution is a blend: use apps where they provide real value, but keep the theme lean and avoid app bloat by building simple features natively.
Conclusion
“App or custom code?” is not a technical question. It is a business question with technical consequences. The right answer depends on whether the feature is a differentiator, what it costs in performance and complexity, and what the long-term risk looks like.
A good Shopify agency will not default to one approach. They will evaluate the goal, the trade-offs, and the lifespan of the store, then recommend the solution that keeps the site fast, stable, and easy to evolve. That judgement is one of the clearest signs you are working with specialists rather than generalists.
We’ll build your store in a way that maximises functionality without affecting stability. Our team of experienced Shopify engineers are ready to help – just contact us to find out how.
