What Does It Cost to Build an Ecommerce App?

An ecommerce app is rarely expensive because of what you see – product lists, cart, checkout. It gets expensive because of what you don’t see: the integrations with the ecommerce platform, inventory levels, product data, and payments. Most projects land between SEK 800,000 and 2.5 million, and it’s the integration layer that decides where in that range you end up.

Price ranges by level

These ranges apply to an app for both iOS and Android built on an existing ecommerce business. If the platform itself is also being replaced or built at the same time, that’s its own project with its own budget.

The integrations are the biggest line item

An ecommerce app never stands alone. It needs to mirror your ecommerce platform (Shopify, Centra, or Norce, for example), show accurate inventory, pull product information from a PIM, and forward orders to business systems and warehouses. Each such connection is its own small project: data models need mapping, error cases need handling, and everything needs testing against real flows.

The rule of thumb: the older and more custom your underlying systems, the bigger the share of the budget the integrations eat up. A modern platform with well-documented APIs can cut the integration work in half compared with an older business system that requires purpose-built connections. That’s why two apps that look identical on the phone can differ by a million kronor in price.

Payment methods: implementation and fees

Checkout is the ecommerce app’s heart and has two cost sides. First, implementation: every payment method – Klarna, Swish, card payment, Apple Pay, and Google Pay – is its own integration with its own certification and testing. Supporting three payment methods costs more than one, but usually converts better; Swedish consumers effectively expect both Swish and Klarna.

Then the ongoing fees: payment providers charge transaction fees that vary with volume and contract – those belong to the running-cost budget, not the development budget. And an important rule that surprises many: for physical goods, Apple and Google take no commission on sales made in the app. The stores’ commission rules apply to digital purchases. A fashion retailer therefore pays the stores nothing per sweater sold, while a service selling digital content in the app has to factor store commission into its margin.

A worked example

A chain with existing ecommerce on a modern platform wants an app for its regular customers: product feeds, cart, Klarna and Swish, push notifications for campaigns and order status. App development itself – flows, design, checkout – accounts for maybe 60 percent of the budget. Integrations with the platform, inventory, and PIM take the rest. Total: around SEK 1–1.2 million and 4–6 months.

Then add the running costs: maintenance at 15–25 percent of the development cost per year, transaction fees, and time for campaign testing ahead of Black Week. That’s a fully reasonable calculation for a chain where app customers buy often – and a questionable one for a store with occasional, infrequent purchases, which is often wiser starting with a really good mobile site.

Note that the push notifications in this scenario aren’t a nice extra but the whole business case: the app is the campaign channel you own, with no ad cost per send, aimed at your most purchase-ready customers.

Keeping the cost down

Build on the platform’s APIs instead of around them, launch with the core flows – browse, buy, track order – and let personalization and loyalty come in version two once you see how the app is used.

Two more things keep the math honest. Size for campaign load from the start – the app needs to handle Black Week traffic, not just everyday flow, and it’s cheaper to build it right than to fight fires in November. And measure from day one: the whole point of the app is the regular customers, so track repeat-purchase rate and push conversion. Those are the numbers that decide whether version two earns its budget. At Weapp we build ecommerce apps in React Native, which gives you both platforms on one codebase; read about our services or get in touch for a price range for your specific system setup.