Mobile app development for iOS and Android

From the first idea to the App Store.

Planning a new app, or taking an existing one further? We cover the whole app lifecycle: from planning to release on the App Store and Google Play, and beyond. Production code we will still stand behind years from now.

For companies and public-sector organisations that need an app for customers, insured members or employees.

Photo: a woman and a man sit at a wooden table in a bright office; she shows him something on her smartphone and both laugh
Platforms iOS · Swift, SwiftUI Android · Kotlin, Jetpack Compose Healthcare · gematik, FHIR, BITV all services

Selected clients

IBMBARMERTechniker KrankenkasseDAK GesundheitMediengruppe RTLEDEKAPeek & CloppenburgDüsseldorfHR-Puls

A new app, or the next stage of the one you have

Whether you want a new app built or need to take an app with many users further, we have a clear path for both, and we can look after the app long term once it is live.

New app

From the first idea to the App Store

Together we work out what the app needs to do. We recommend the right technology and build the app for iOS, Android or both platforms.

  • Analysis workshop and effort estimate before the start
  • Early test builds you try out yourself
  • Release on the App Store and Google Play
Request an analysis workshop →
Existing app

Take over, modernise, extend

We take over existing apps, bring them up to date and keep building on them: new features, a new design, or several apps on one shared platform.

  • Code analysis with a clear recommendation
  • Step-by-step modernisation while the app stays in the store
  • Maintenance and updates for new iOS and Android versions
Talk about your app →

iOS and Android app development from one team

Strategy, creativity and technology from one team. We build apps that fit your users and your systems. Every app comes with automated tests, a pipeline for new versions and documentation that your own team can work with too.

01iPhone·iPad·Widgets

iOS app development

Apps for iPhone and iPad in Swift and SwiftUI. We use what the platform offers: widgets, Apple Health, in-app purchases, push notifications and Sign in with Apple.

Technology
Swift, SwiftUI, UIKit, Swift Concurrency
Platform
WidgetKit, HealthKit, StoreKit, App Intents
Result
App on the App Store, source code with you
Request a project
02Smartphone·Tablet

Android app development

Apps for Android smartphones and tablets in Kotlin and Jetpack Compose. Released on Google Play, with a staged roll-out to part of your users if you wish.

Technology
Kotlin, Jetpack Compose, Java
Platform
Android smartphones and tablets
Result
App on Google Play, source code with you
Request a project
03Strategy·UI/UX·Project management

Product & UX

Strategy, UI/UX design and project management. We combine creativity, innovation and reliable delivery: well-designed interfaces that simply work in everyday use.

Service
Concept, UI/UX design, prototypes
Tools
Figma, Sketch
Result
A design your users understand
Request a project
04Existing app→up to date

Takeover, modernisation and maintenance

We take over existing apps and keep them current: new iOS and Android versions, security updates, new features. We bring several apps together on one shared platform and move older codebases up to date step by step.

Service
Takeover, updates, new features
Scope
As agreed, with named contacts
Result
An app that runs on every platform version
Request a project

Patient-centred apps in the German healthcare stack

We deliver into Germany's telematics infrastructure, the regulated layer between patients, health insurers and clinical systems: with the electronic patient record (ePA) and our own consumer health product, Quantlife.

What we build
  • 01

    ePA front end and white-label SDK

    The electronic patient record app for insured members, as a white-label SDK for several health insurers.

  • 02

    gematik specifications MIO · eMP · AMTS · VAU+

    Medical information objects such as the maternity record and vaccination record, the medication plan and medication safety checks, and the connection to the trusted execution environment.

  • 03

    FHIR data integration

    Reading, displaying and transferring health data in the FHIR standard.

  • 04

    Accessibility BIK BITV · WCAG 2.1 AA

    Tested with the BIK BITV test, built to WCAG 2.1 AA.

  • 05

    GDPR-compliant data handling

    Health data handled to gematik requirements and the GDPR.

  • 06

    Consumer health apps

    Calorie tracking and HealthKit pipelines, for example in Quantlife.

Healthcare
  • A

    IBM

    Front end for insured members (ePA) and white-label SDK.

  • B

    BARMER · Techniker Krankenkasse · DAK · Knappschaft

    Statutory health insurers whose members use the ePA app.

  • C

    Quantlife

    Our own consumer health product for iOS.

Accessible apps, secure data, clean releases

An app has to work for every user, handle sensitive data correctly and stay stable with every new version. These standards apply to every app we build.

Photo: a man sits smiling at a desk in a bright open-plan office and tests an app on two smartphones
  • 01

    Accessibility to WCAG 2.1 AA

    Works with VoiceOver and TalkBack, large text and sufficient contrast, in every app and not only in healthcare.

  • 02

    Security and data protection

    Sign-in with OAuth 2.0, OpenID Connect, netID or Sign in with Apple, encrypted transfer, no trackers without user consent.

  • 03

    Automated tests

    Unit, UI and snapshot tests run on every change. A change that fails a test does not reach the app.

  • 04

    Release pipeline

    Every version is built, tested and distributed as a test build automatically, with GitLab CI or GitHub Actions, Fastlane and TestFlight. A developer checks it and releases it to the App Store and Google Play.

Frequently asked questions about app development

More questions? Write to us.

How much does it cost to have an app developed?+
It depends on the scope: platforms, number of features, connected systems and requirements for data protection and accessibility. After the analysis workshop you receive an effort estimate and know what to expect.
How long does it take to develop an app?+
That also depends on the scope. After the workshop you receive a schedule. You get a first test build for your own device early in the project, not only at the end.
iOS, Android or both?+
It depends on which devices your users have. For customers and insured members it is usually both platforms. We discuss which technology suits your app in the analysis workshop.
Do you also build healthcare apps?+
Yes. From the ePA app we know the gematik specifications (MIO, eMP, AMTS, VAU+), FHIR and the requirements for accessibility and data protection. On top of that comes our own health app, Quantlife.
Can you take over our existing app?+
Yes. We look at the code, tell you openly what state it is in and recommend a path: keep building on it, modernise it step by step or rebuild parts of it. The app stays in the store throughout.
Is the app accessible?+
Yes. We build to WCAG 2.1 AA: works with VoiceOver and TalkBack, large text and sufficient contrast. In the workshop we check whether the German Accessibility Act (BFSG) applies to your app.
Who owns the source code?+
You do. You receive the source code and the documentation, and the app is published under your own account on the App Store and Google Play.

btaq GmbH. Custom software engineering.

As an app development company, we plan, design and build apps with our own development team, for companies and public-sector organisations. We also build system integrations and AI automation. You talk directly to the developers who plan, build and maintain your app.

  • LocationDüsseldorf, Germany · HRB 85733 · founded 2019
  • ExperienceePA app for statutory health insurers, EDEKA app, wetter.de app, our own health app Quantlife
  • PlatformsiOS and Android
  • DeliveryConcept, development, release and maintenance from one team

Which app do you want to build?

Book a free first call, or write to us what your app should do and who it is for. New app or existing one: we answer in person.