Mobile developers build the apps people open every day, handling small screens, offline use, battery and app store releases. It suits you if you love polished apps and want to own a product end to end. A published app with real users is the strongest signal you can show. Not sure? Take the 2-minute career quiz or compare tracks in the explorer.
Choose a platform & learn its language
Pick one: native Android with Kotlin, native iOS with Swift (needs a Mac), or cross-platform with Flutter and Dart. Depth in one beats shallow knowledge of three.
WHAT TO LEARN
- Kotlin, Swift or Dart fundamentals
- Object-oriented and functional basics
- Null safety and error handling
- Asynchronous code: coroutines, async/await or futures
YOU SHOULD BE ABLE TO DEMONSTRATE
- Solve small problems in your chosen language without a tutorial
- Explain how null safety prevents crashes
- Write asynchronous code that does not freeze the UI
COMMON MISTAKES
- Switching between Flutter, React Native and native every month.
- Learning Swift without access to a Mac to build and test.
FREE RESOURCES
- Kotlin Koans and official Kotlin docs
- Dart language tour (dart.dev)
- Apple Swift Playgrounds and Develop in Swift — free
UI, layouts & navigation
Users judge apps in seconds. Clean layouts and smooth navigation are the core of the job.
WHAT TO LEARN
- Declarative UI: Jetpack Compose, SwiftUI or Flutter widgets
- Lists, forms and responsive layouts
- Navigation between screens and passing data
- Design guidelines: Material Design and Apple HIG
YOU SHOULD BE ABLE TO DEMONSTRATE
- Build a three-screen app with navigation
- Create a scrolling list that stays smooth with many items
- Follow platform design guidelines for a form screen
COMMON MISTAKES
- Ignoring different screen sizes and dark mode.
- Building custom components for things the platform already provides.
FREE RESOURCES
- Android Basics with Compose — free Google course
- Flutter official codelabs
- Material Design and Apple Human Interface Guidelines
State & app architecture
As apps grow, structure matters. Interviewers check whether your code would survive in a team codebase.
WHAT TO LEARN
- State management: ViewModel, Provider, Riverpod or similar
- Separating UI, logic and data layers
- Dependency injection basics
- Handling configuration changes and lifecycle
YOU SHOULD BE ABLE TO DEMONSTRATE
- Explain how state flows through your app
- Rotate the device without losing data
- Move business logic out of UI code
COMMON MISTAKES
- All logic inside one giant screen file.
- Global variables used as state management.
FREE RESOURCES
- Android app architecture guide (developer.android.com)
- Flutter state management documentation
- Official Riverpod / Provider docs
Networking & data persistence
Almost every app talks to a backend and needs to work with poor connectivity — common in many markets.
WHAT TO LEARN
- Calling REST APIs and parsing JSON
- Local storage: Room, SQLite or Hive
- Offline-first patterns and caching
- Authentication with tokens or Firebase
YOU SHOULD BE ABLE TO DEMONSTRATE
- Load data from an API with loading and error states
- Keep the app usable offline
- Log in and keep the session securely
COMMON MISTAKES
- Freezing the UI while waiting for the network.
- Storing tokens or passwords in plain text.
FREE RESOURCES
- Retrofit and Room official guides
- Flutter networking cookbook
- Firebase documentation (free tier)
Platform features
Device features make mobile apps valuable beyond a website — and handling permissions properly builds user trust.
WHAT TO LEARN
- Runtime permissions and privacy
- Push notifications
- Camera, location and sensors
- Background work and battery limits
YOU SHOULD BE ABLE TO DEMONSTRATE
- Request a permission only when needed and handle refusal gracefully
- Send and receive a push notification
- Use location or camera in a real feature
COMMON MISTAKES
- Asking for every permission on first launch.
- Running background tasks that drain the battery.
FREE RESOURCES
- Android permissions and WorkManager guides
- Firebase Cloud Messaging docs
- Flutter plugins documentation on pub.dev
Testing, performance & debugging
Crashes and slow apps get uninstalled and poorly reviewed. Teams value developers who catch problems before release.
WHAT TO LEARN
- Unit tests for logic
- UI tests for key flows
- Profiling memory, CPU and frame rate
- Reading crash reports
YOU SHOULD BE ABLE TO DEMONSTRATE
- Unit tests for your view models or business logic
- A UI test for login or checkout
- Find and fix a slow screen with the profiler
COMMON MISTAKES
- Testing only on one high-end phone.
- Ignoring crash reports after release.
FREE RESOURCES
- Android testing documentation
- Flutter testing cookbook
- Firebase Crashlytics docs
Publishing & release
Shipping to a store proves you can finish. It is also where many self-taught developers stop short.
WHAT TO LEARN
- App signing and build variants
- Store listings, screenshots and privacy policies
- Versioning and staged rollouts
- Collecting feedback and analytics responsibly
YOU SHOULD BE ABLE TO DEMONSTRATE
- An app live on the Play Store or App Store
- A store listing with screenshots and a privacy policy
- Release an update with a changelog
COMMON MISTAKES
- Waiting for the app to be perfect before publishing.
- Missing a privacy policy, which stores require.
FREE RESOURCES
- Google Play Console help center
- Apple App Store Connect help
- Flutter deployment guides
Mobile app projects for beginners
Three projects, each harder than the last. Interviewers would rather see one finished, deployed project you can explain than ten half-done tutorials.
Habit or prayer-times tracker
2–3 weeksSmall, useful and focused on clean UI.
- Three screens with navigation
- Local storage so data persists
- Works in light and dark mode
- Source on GitHub with screenshots
Weather or news app with offline mode
3–5 weeksReal API data that still works without internet.
- API integration with loading and error states
- Offline caching
- Clean architecture with state management
- Unit tests for logic
Published community app
6–8 weeksAn app real people can download and use.
- Authentication and a backend such as Firebase
- Push notifications and one device feature
- Live on the store with a privacy policy
- Crash reporting and at least one update released
Interview preparation
Most junior mobile interviews have four parts. Prepare for each separately — candidates often over-prepare algorithms and under-prepare explaining their own project.
| Round | What they check | How to prepare |
|---|---|---|
| Screening | Language fundamentals and problem solving | Practise small problems in Kotlin, Swift or Dart. |
| Technical interview | UI, lifecycle, state and networking | Explain your architecture and how your app handles rotation and offline use. |
| App walkthrough | A real app you built and shipped | Demo your published app and discuss one hard bug you fixed. |
| Behavioural | Product thinking and teamwork | Prepare a story about user feedback that changed your app. |
Are you ready for entry-level roles?
Tick honestly. If you can do at least 8 of these 10 without looking things up, start applying — you will learn the rest on the job.
Written by Mubashar Hussain · Founder, TechCareerWay
Engineering leader with 20 years building software and hiring developers across 7 countries. Are you a working mobile engineer? Become a technical reviewer for this guide. Spotted an error? Tell us.