Recommended expert

Rafael Kolloch

Senior Android Developer / Team-Lead

Rafael Kolloch
Dortmund, Germany

Experience

Feb 2021 - Apr 2025
4 years 3 months

Senior Android Developer / Team-Lead

IBM Deutschland

  • Further development and release support of a white-label e-prescription component for health insurance companies
  • Technologies: Android (Kotlin), Kotlin Multiplatform, Coroutines, Jetpack Compose, MVVM, StateFlow, Gradle, ProGuard
Jul 2020 - Dec 2020
6 months

Android Developer

ZGS Bildungs-GmbH (Deutsche Schülerhilfe)

  • Concept, architecture, development and deployment of the new online tutoring app for Deutsche Schülerhilfe
  • Technologies: Android (Kotlin), AndroidX, Android Jetpack, MVVM, LiveData, Room (SQLite), Retrofit, Gson, Firebase, push notifications, Zendesk, Gradle, ProGuard
Apr 2020 - Present
5 years 10 months

Full-stack Developer

Selbstständig

  • Development and maintenance of the research platform for stock investors "Trader Radar"
  • Technologies: Android (Kotlin), AndroidX, Android Jetpack, MVVM, LiveData, Room (SQLite), Retrofit, Gson, Firebase (Cloud Messaging, Crashlytics, Remote Config), in-app purchases, AdMob, Gradle, ProGuard, PHP, MySQL, HTML, CSS, JavaScript
Jan 2019 - Mar 2020
1 year 3 months

Lead Developer

Deutsche Bank

  • Lead development of a prototype and the subsequent design, deployment, and ongoing enhancement of a mobile payment app
  • Accompanying security audits and hardening
  • Technologies: Android (Kotlin), AndroidX, Android Jetpack, Room (SQLite+SQLCipher), Retrofit, Gson, Bluetooth, NFC, native communication with card terminals, encrypted databases and communication, Gradle, ProGuard, JUnit, Robolectric, Mockito, MockK
Jan 2019 - Dec 2019
1 year

Lead Developer

Leading German construction machinery provider

  • Lead development of a trade fair companion app
  • Technologies: Android (Java/Kotlin), AndroidX, Android Jetpack, Swagger CodeGen, encrypted databases and communication, Gradle, ProGuard, JUnit, Robolectric, Mockito, MockK
Jan 2017 - Present
9 years 1 month

Full-stack Developer

Self-Employed

  • Full-stack development of the math games app "Crystal Math"
  • Technologies: Android (Java), Google Standard Frameworks, SQLite, Retrofit, Firebase (Cloud Messaging, Real Time Database, Remote Config, Crashlytics), Facebook SDK, Gradle, ProGuard, PHP, MySQL
Jan 2017 - Dec 2019
3 years

Lead Developer

Leading German logistics company

  • Designing, deploying and continuously improving a comprehensive mobile app
  • Performing security audits and hardening
  • Technologies: Android (Java), Google Standard Frameworks, Dagger2, SQLite, Retrofit, Swagger CodeGen, database and communication encryption, Gradle, ProGuard
Jan 2017 - Dec 2017
1 year

Android Developer

Leading German automotive supplier

  • Development of a companion app for light e-mobility vehicles
  • Technologies: Android (Java), Bluetooth LE, database and communication encryption
Jan 2015 - Dec 2016
2 years

Android Developer

Swiss Bank

  • Development of a mobile banking app in close collaboration with the client's team
  • Technologies: Android (Java), Android-JavaScript bridge, communication encryption

Skills

  • Activity Areas: Architecture, Consulting, Development, Feasibility Analysis
  • Programming Languages: Kotlin, Java, Objective-c, Swift, Php
  • Ides: Android Studio, Intellij Idea, Xcode, Eclipse, Netbeans, Visual Studio Code
  • Industries: Automotive, Banking, Logistics, Lottery, Public Sector, Retail, Utilities, Insurance
  • Android: Android Sdk, Kotlin Multiplatform, Jetpack Compose, Koin, Dagger2, Coroutines, Mvvm, Mvp, Mvi, Room, Livedata, Sqlite, Sqlcipher, Retrofit, Okhttp, Gson, Firebase (Ads, Cloud Messaging, Crashlytics, Realtime Database, Remote Config), Admob, Glide, Picasso, Timber, Material Design Ui, Biometric Authentication (Fingerprint), Gradle, Unit Tests, Junit, Mockito, Mockk, Robolectric, Release Management
  • Ios: Afnetworking, Cocoapods, Cocoalumberjack, Firebase (Ads, Crashlytics, Cloud Messaging), Release Management
  • Misc: Regular Expressions, Reverse Engineering, Pentesting, Web Scraping
  • Project Management / Ci: Scrum, Atlassian Toolchain, Jira Administration/customization, Bitbucket, Jenkins, Teamcity, Sonarqube
  • Databases: Sqlite (With Sqlcipher), Mysql, Oracle, Db2, Postgresql
  • Platforms: Windows, Linux/unix, Macos
  • General It Skills: Common Office Suites Like Ms Office And Open Office, Experience With Graphics Editing Tools Like Photoshop, Gimp

Languages

German
Native
English
Advanced
Polish
Advanced
Spanish
Elementary

Education

Oct 2004 - Jun 2010

TU Dortmund

Diploma · Computer Science · Dortmund, Germany

Oct 2001 - Jun 2004

FernUniversität in Hagen

Part-time distance learning · Computer Science · Hagen, Germany

Aug 2001 - Jul 2004

Training as an IT Specialist (Application Development)

Vocational Training · IT Specialist (Application Development) · Dortmund, Germany

...and 1 more
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