Tom
Seifert
M.Sc. in Computer Science
Freelance app developer from Dortmund
I develop your app professionally and customised - either as a native Android app or cross-platform with Kotlin and Compose Multiplatform. I rely on the latest standards and a high level of quality: my goal is to realise the best possible solution for you. With the act like an owner approach, I take responsibility for every detail in order to realise your vision in the best possible way. See for yourself in our next joint project!
You can also find me on
Get to know me!
With over a decade of experience in Android and app development, I offer extensive expertise in creating, maintaining and optimising mobile applications. As an Android developer, I have successfully managed projects for renowned companies such as JAKALA Germany GmbH and Zalando Payments GmbH, developing innovative solutions and creating complex libraries and enterprise apps with millions of users.
My broad knowledge of technologies such as Kotlin, Jetpack Compose, Coroutines and Kotlin Multiplatform, combined with my experience in iOS and backend development, enables me to design and implement high quality and maintainable software architectures. I am also experienced in using CI/CD pipelines and test automation (unit tests, UI tests, screenshot tests).
I look forward to assisting you with your next project and working with you to make your mobile application a success.
in software development
years of experience with developing Android apps
years of experience in renowned German companies
My services
Besides app development, I support you in all areas of software development and project management.
App development
Professional & high quality development of your native Android app according to modern standards. Also cross-platform with Compose or Kotlin Multiplatform.
Consulting & Analysis
Consulting around the topic of mobile apps. I am also happy to support you with feasibility studies or inspect the quality of existing code.
Technical Leadership
I can help you with project planning, ticketing, or leading and mentoring your existing team.
together to the next level
If desired, I contribute my own ideas and suggestions or design and optimize UI/UX of your app.
My skills
You can get more detailed information about my experience in a personal conversation.
Android Core
- Android SDK
- Android Studio / IntelliJ
- Gradle (Kotlin DSL)
- Android Jetpack libraries
- Jetpack Compose
- WearOS
- Firebase
Languages
- Kotlin
- Coroutines
- Flow
- Native
- Multiplatform
- Java
- Swift & Xcode
- JavaScript/TypeScript
- Flutter/Dart
Testing
- JUnit 4 & 5
- Kotlin Coroutine testing
- Espresso UI
- Screenshot testing
- Mockito/mockk
Coding
- Git (gitflow)
- CI/CD
- Creating/maintaining pipelines
- GitHub Actions
- Jenkins
- Travis
- Object-oriented programming
- Clean Code
- Clean Architecutre
- MVP/MVVM/MVI/Redux
- REST & GraphQL
Showcase
I published gemli in 2018 and have been developing it ever since. The app has many modern features, such as light/dark theme, dynamic adjustment of the color tone based on the background image (from Android 12) or language selection (from Android 13).
The app follows Clean Architecture, includes screens in Jetpack Compose, and I specifically taught myself backend development with Ktor to replace the initial but error-prone Firebase Realtime Database to serve the app data with a dedicated server.
Firebase
Messaging, Crashlytics, Analytics, Ads, Remote Config
Android
OkHttp, Retrofit, Room, ViewModel, Coroutines, Material 3, Billing, In-app review and more
Jetpack Compose
New screens are written in Jetpack Compose and seamlessly linked to traditional views
Backend
Ktor JVM server with PostgreSQL connection. Also Firebase admin integration and monitoring via Grafana.
Offline-first
The app is primarily designed for offline functionality and works even where users have no network
Bewertung
4,6 stars (02/23) and 99,9% users without a crash
Contact me via +49 15678 204 292
or