Hire an app developer: how to judge skills, portfolio and price

Picture a managing director with a good idea for a customer app. He has three quotes: DKK 45,000, DKK 280,000 and DKK 650,000. All three say "iOS and Android", and all three have beautiful screenshots in their portfolio. The difference only shows when you dig in: the cheapest has left out the backend and admin panel, the middle one builds one codebase, and the most expensive builds two native apps with two teams. All three can be fair quotes. They simply answered three different briefs. Hiring the right app developer therefore starts with understanding what you are buying, before you compare prices.

What skills should an app developer have?

An app is rarely just an app. Behind the screens sit login, data, payments, notifications and a place where your staff work. Use this list to check whether the developer or team covers the whole job, and mark what is relevant to you:

• Mobile UI: navigation, forms and animations that feel natural on both iPhone and Android.
• Backend and API: database, users, permissions and connections to your other systems.
• Login: email, Apple and Google sign-in, or MitID if you need to know the user’s identity.
• Payments: MobilePay, Stripe, subscriptions and in-app purchases under the store rules.
• Push notifications, offline use, camera and location where relevant.
• Publishing: certificates, build pipelines, App Store and Google Play review.
• Testing on real devices and crash monitoring after launch.
• Security and GDPR: encryption, access control, logging and data deletion.

Few freelancers are strong on every point, and that is fine. What matters is that you know who fills the gaps. If you are missing a designer, read our guide to hiring a UX designer. If a web version is needed too, see hire a web developer.

React Native, Flutter or native: which app developer should you look for?

The technology choice decides which developers you look for and what it costs to maintain the app for years. There are three main tracks. Native means Swift for iOS and Kotlin for Android, that is two separate apps. Cross-platform means one codebase running on both, typically in React Native (JavaScript/TypeScript) or Flutter (Dart).

We build in React Native and TypeScript ourselves, so we have a stake in this choice, and we say so openly: for apps with many user roles, integrations and a web admin panel, one codebase in one language is hard to beat. For a game or an app built around the camera, native is often right. See how we work under React Native app development, and read web app vs native app if you are not yet sure you need to be in the stores.

What does an app developer cost in 2026?

Add 15–20 % of the build cost every year for maintenance. You will find the full price picture, including what drives it, in how much an app costs.

Worked example: a booking app for a chain with four locations

A chain with four locations wants an app where customers book appointments, pay with MobilePay and get a reminder the day before. Staff need to see bookings in a web admin panel. A freelancer estimates 250–400 hours at DKK 1,000, so DKK 250,000–400,000, which sits squarely in the market range for a medium-complexity app. Add maintenance of 15–20 % a year, that is DKK 37,500–80,000. If the scope fits 24 features and 2 integrations, we can build it in our Medium package at DKK 48,000 plus DKK 1,800 a month, with hosting, maintenance and updates included. The right choice depends on whether you want a person to manage or a team on a fixed price.

How do you check an app developer’s portfolio?

Screenshots in a PDF say very little. An app is proven once it is in the store and being used. Do this with three apps from the portfolio:

1. Download the app from the App Store and Google Play. Is it in both, and does it work?
2. Check the date of the latest update. An app not updated for over a year is worth a question.
3. Read the reviews, especially the bad ones. Are they about crashes, login or slowness?
4. Ask what the developer built personally: the app, the backend, the admin panel or all of it?
5. Ask whether they handled store submission themselves, and whether the app was ever rejected.
6. Ask to speak with the client behind one of the apps.

Experience with rejections is a plus. It means the developer knows Apple’s and Google’s guidelines in practice. We have collected the typical causes in the guide to App Store approval. An example from our own portfolio is Kirppu, where an app for labelling items is part of a larger system with stand booking and a renter panel. That kind of connection between app and system is worth asking about.

Which questions should you ask an app developer?

Where do you find an app developer?

The same sources as for web developers work here: your network, LinkedIn, Jobindex, The Hub and international platforms such as Upwork and Toptal. An extra trick is to work backwards from the store: find apps you like in the App Store and look at the developer name under the app. It is often an agency or a freelancer you can contact directly. Also search by technology, such as "React Native developer", so you reach profiles that match your choice.

Also consider which model fits. A freelancer is flexible and often cheaper per hour, but you manage the work yourselves and fill the gaps in design, testing and operations. An agency or studio covers several crafts and carries more of the responsibility. An employee makes sense when the app is your core product and there is work for years. Developers abroad can lower the hourly rate but need more management. We have written about the trade-off in freelancer vs agency and outsourcing software development.

Which red flags should you know?

• The price only mentions "the app" and nothing about backend, admin panel or hosting.
• The app will be published on the developer’s own store accounts.
• No apps in the stores to show, only designs.
• No plan or price for maintenance after launch.
• The developer promises App Store approval on a specific date.
• Everything has to be built native without a reason that fits your app.

How to hire an app developer step by step

We are one of the options. We are a senior team in Copenhagen with design and development under one roof, we build one app for iOS and Android in React Native, and you get a written fixed-price proposal within 24 hours. Our mobile packages start at DKK 28,000 plus DKK 1,200 a month. See them under mobile apps, or describe your app here. If you would rather hire yourselves, we hope the checklists here make it easier to choose well.