Most retail sales still happen in physical stores. In the US, online sales made up 17.1% of total retail sales in the second quarter of 2026, according to the U.S. Census Bureau. In Great Britain the online share was 28.8% in September 2026, according to the Office for National Statistics. So if you run stores, your app’s job is to help people buy from you wherever they decide to: check whether a nearby store has the item, buy or reserve online and collect, carry a loyalty card that updates itself, and get an offer they can use in the aisle. Trend lists from 2022 put mixed reality and robot shopping carts next to these features. For most retailers the spending order is simpler, and it starts with stock data you can trust.
| Feature | What the shopper gets | What you need behind it |
|---|---|---|
| Stock at a nearby store | Knows the item is there before making the trip | Stock per store, synced from the till system often enough to trust |
| Buy or reserve online, collect in store | Skips the delivery wait and the shipping fee | Orders routed to a store, a pick list for staff, a “ready” message |
| Loyalty card in the phone’s wallet | Points and offers with no app to install | A wallet pass that updates when the balance changes |
| Local and timely offers | A deal that fits where they are and what they buy | Opt-in, a limit on how often you message, and offers tied to real stock |
| In-store scan | Sizes, reviews and other colours from a barcode | Clean product data with one ID per product |
| Staff tools | Fast answers on the shop floor | The same stock and order data on a staff phone or tablet |
The order matters because each feature depends on the one above it. Click and collect breaks if stock is wrong. Offers annoy people if the item is sold out. Start with the data.
You may not need a full app to run a loyalty card. A pass in Apple Wallet or Google Wallet does that job, and the shopper doesn’t install anything.
Apple’s Wallet developer page says store cards can hold loyalty, discount, points and gift cards, and can be updated to show the current balance. Coupons can be updated with a new offer and expiry date, and passes can come up based on location. On Android, Google’s loyalty card guide for Google Wallet says passes can be issued anywhere a link works, including websites, email and SMS. A shopper can get your card from a receipt email and use it in the store the same afternoon.
Build a full app when shoppers come back often enough to keep it on their phone, or when the app does something a pass can’t, like a shopping list tied to store stock or a points game. LEV is a good example of that second case. It’s a map app for urban dog owners we built with Flutter for iOS and Android: people earn rewards on their daily walks and turn them into discounts at partner businesses. It went from project start to market launch in 4 months, with 15+ partner businesses and an admin panel just for them. That’s the link a store app needs: what people do in the app becomes a reason to visit a shop.
Shoppers forgive a plain design. They don’t forgive a trip to a store that says “in stock” on the phone and “sold out” at the shelf. Before you design screens, find out how often your till system can share stock per store, and plan a safety margin so the app hides items that are about to run out.
Product data comes next. Each product needs one ID across the website, the app, the till and the wallet offers. Without it, the in-store scan shows the wrong item, and your reports count one product as three.
Some retailers also need to know what’s on the shelf right now. Eyrene, a retail audit product we integrate for its customers, recognises products from photos instead of a person counting them by hand, with recognition accuracy above 95%. Most retailers won’t need that on day one. It shows where shelf data can come from once the basics work.
The old “new normal” advice was to talk to shoppers gently. That still holds, and the product can enforce it. Ask before sending notifications. Cap how many messages a person gets each week. Tie every offer to something the shopper can buy today at a store near them. A discount on a sold-out item teaches people to ignore your messages.
On iPhone the opt-in is Apple’s rule, not only good manners. Guideline 4.5.4 of the App Store Review Guidelines says push notifications shouldn’t be used for promotions or direct marketing unless customers have explicitly opted in through consent wording in your app, and the app gives them a way to opt out. Build both screens into the first release.
If you sell to consumers in the EU, plan for accessibility from the first screen. The European Accessibility Act has applied since 28 June 2025, according to AccessibleEU, the European Commission’s accessibility centre. The Commission’s list of covered services includes e-commerce. Ask your team to design and test for it from the start, because fixing it later means redoing screens. Check with a lawyer whether your business is covered; this guide isn’t legal advice.
Pick the numbers before launch, so each feature has to prove itself. For a store app, we’d watch these:
If pickups lag behind orders, look at the “ready” message and the pickup desk before you add features. If staff keep reporting sold-out items the app showed as in stock, fix the sync before you spend anything on marketing.
Mixed reality fitting rooms, smart carts and robot assistants make good headlines. Keep them off the first budget unless you’ve already got accurate stock, working click and collect and a loyalty program people use. Each of them also depends on the same stock and product data, so the work you put into the basics isn’t wasted.
Each row of the feature table becomes a few user stories. You can run your store app idea through our project estimate: it turns a short brief into those stories, you confirm which are in scope, and every hour in the budget traces back to a story you kept. We check the hours the AI suggests against what our team actually books on finished projects, then multiply by our published rate of $39-55 an hour.
Leave offers and in-store scanning unchecked, and you see what stock, click and collect and the wallet card cost on their own. The result is a planning range, not a fixed quote.
Our mobile app development page shows how we build one app for iPhone and Android. Our web app development page covers the web store and staff tools. The LEV build is in the LEV case study. If you sell across EU borders, see what a store must build in for selling online in Europe. If you want to sell through live video, read our guide to live shopping and social commerce.
Stock at a nearby store, buy or reserve online and collect in store, and a loyalty card. Location and time offers, in-store scanning and staff tools come after, because they all depend on accurate stock and product data.
Not always. An Apple Wallet or Google Wallet pass can hold a loyalty card, show an updated balance and carry offers. Google says its passes can be issued from websites, email and SMS, so shoppers don’t install anything.
In the US, online sales were 17.1% of total retail sales in the second quarter of 2026, according to the Census Bureau. Most retail sales still happen in physical stores.
Sync stock per store from your till system as often as it allows, and hide items that are close to selling out. Wrong stock data does more damage than a missing feature.
With us, a first version of one app for iPhone and Android typically costs $5,000-15,000 and takes 2-4 weeks, plus store review. Bigger scopes, such as integrations with your till and stock systems, are priced by the hour at $39-55.
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