A medical app that works offline
I was responsible for offline data handling and the Bluetooth injector connection, and led five mobile developers.
Mobile app
Mobile app development: what it costs and how it works
I build iOS and Android apps from one codebase (React Native, Expo), from interface design to store release. This page explains what drives the price of an app and how we start, so you can see the ballpark before the first call.
The situation
What drives the cost of a mobile app?
Mostly how many separate things the first version has to do. A login, one main feature and notifications are a different job from an app that also takes payments, shows a map and works offline. The first version gets what you cannot launch without.
It also matters whether the app needs a backend and an admin interface, and which systems it connects to (payments, invoicing, CRM). Bluetooth devices or health data mean more testing and documentation, and that shows in the price.
The iOS and Android versions share one codebase, so the second platform does not double the price. If you launch on one platform only, I price for that one.
What I build
What do you get?
- iOS and Android app from one codebase (React Native, Expo)
- Interface design for the main screens, if you do not have your own yet
- Backend and admin interface, if the app has to store or manage data
- Release on the App Store and Google Play, under your own developer accounts
- Small fixes shipped without store approval (OTA)
- Automated tests, and analytics set up so you can see how many people use the app and for what
How do we start?
The first step is a free 30-minute call. After that, depending on the job, there are three ways to continue, and you see the price of each one up front.
Illustrative introductory prices · until 31 December 2026
30-minute call
free
You tell me where things stand, and we agree which starting point fits.
Technical audit
€880
A risk list and a written recommendation on what to do next.
Discovery and plan
€2,150
A defined scope, a phased plan and an itemised proposal.
First development phase
from €5,200
A usable first version covering the essential workflow.
Amounts are illustrative, with no VAT added. After the call or discovery I give you the exact price in writing.
Full pricing and how estimates workSample estimate
A similar sample job, priced with the same rules as the Workshop. You can get an estimate for your own project there.
A first version for a startup, on iOS and Android
6–13 weeks€10,600–22,000
You have an idea and some funding, and need a working app to show investors and your first users. Sign-in, the core feature, payments and notifications, nothing more. The core feature is deliberately generic here: a specific product gives a more precise figure.
Bringing an existing mobile app up to date
4–8 weeks€6,200–14,000
The app exists, but updates keep failing, the store release breaks or the original developer has gone. You need someone to move it to current tooling, fix the bugs and release it again. In practice the first step is the audit (2 days); the sample assumes the code is in hand only so that a range can be shown.
Related work
A route planner for night-time walks
I designed the system from the mobile app to route calculation, using millions of crime, street lighting and CCTV records.
Biometric sign-in without a rewrite
I added face and fingerprint sign-in to existing apps and made their data fetching consistent.
Questions
How much does a simple app cost?
The smallest standalone first version is the first development phase, 12–16 working days. If the job is bigger, you get an itemised price at the end of the scoping and plan. Below you can also see a sample estimate for a new product: login, main feature, payments and notifications, on iOS and Android.
I already have an app, but it has stalled. Do you take that on?
Yes. I start with a two-day audit: I review the code, the release process and the risks, and recommend in writing what is worth fixing, extending or replacing. If you continue with me, the full audit fee is credited against the first development phase.
Who owns the app?
You do. The source code sits in your repository, and the App Store and Google Play accounts are in your name. If someone else takes it over later, they can carry on from the handover documentation.
Tell me where things stand
A few sentences about the situation and what you want are enough. I reply within one working day, and we book a 30-minute call.