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In the evolving world of Android development, using well-designed libraries isn't just a productivity hack — it's essential. The right dependencies can save you hundreds of hours, reduce boilerplate, help you ship robust apps faster, and avoid reinventing the wheel. In 2025, with Kotlin, Jetpack Compose, coroutines, and modern architecture taking center stage, the “must-know” library list has evolved too. In this post, we'll walk you through the essential Android libraries you should know — from UI to networking to testing — complete with code examples, trade-offs, and best practices.

1. Jetpack Compose (UI / Declarative UI)

• Jetpack Compose is Google’s modern, Kotlin-based declarative UI toolkit. You define UI in composable functions, and it takes care of updating them when state changes. Wikipedia+1

• It is increasingly becoming the default over XML layouts. MoldStud+1

• Why include it: reduces boilerplate, better tooling support, seamless integration with state, theming, animations.

• Key features:

  • @Composable functions

  • State management & remember

  • Modifiers, layouts, lazy lists

  • Animations, transitions

  • Interop with existing Views / XML

• Caveats / Considerations:

  • Learning curve if you come from XML + View system

  • Migration strategy in existing apps

  • Performance pitfalls (e.g. recomposition boundaries)

2. Hilt / Dagger (DI)

• Dependency injection helps decouple modules, make testing easier, maintain modular architecture.

• Dagger + Hilt: Hilt is a relatively higher-level, opinionated wrapper over Dagger specialized for Android. Many blogs and sources list it as a must-know library. Medium+2MoldStud+2

• Pros: compile-time safety, good performance, integration with Android components.

• Cons: verbose generated code, steep learning curve, sometimes heavy setup.

• Alternatives: Koin (lighter, no code gen) is also gaining traction, especially in Kotlin projects. Medium

3. Retrofit + OkHttp (Networking / API)

• Retrofit is a type-safe HTTP client for Android/Java, built by Square. It wraps lower-level HTTP libraries like OkHttp. netguru.com+3GeeksforGeeks+3RipenApps Technologies+3

• Handles JSON (or other formats) -> POJOs / Kotlin data classes, parameter binding, headers, retry strategies.

• OkHttp underneath gives you control over connection pooling, caching, interceptors, TLS, etc.

• Why include: almost the de facto standard for REST / HTTP in Android.

• Points to note: error handling, cancellation, coroutine / suspend / Flow support (with adapters) in modern usage.

4. Room (Jetpack)

• Room is Google’s own ORM / persistence library over SQLite. It gives compile-time query checking, observable data support (LiveData / Flow), seamless integration with other Jetpack components. Medium+2MoldStud+2

• Why include: safer than raw SQLite, reduces boilerplate, better maintainability.

• Points: migrations, handling large data, fallback strategies, join queries, relation mapping, performance considerations.

5. Kotlin Coroutines / Flow

• Asynchronous programming is essential in mobile (network calls, DB, I/O). Coroutines + Flow are now the recommended Kotlin-first approach. MoldStud+1

• Flow is for reactive streams, combining well with Compose, Room, Retrofit, etc.

• You can mention e.g. suspend functions, flow, channel, flowOn, stateFlow, sharedFlow.

6. Glide / Coil / Picasso (Image Loading & Caching)

• Loading images efficiently (with caching, resizing, memory efficiency) is a recurring need.

• Glide is a popular, efficient option. RipenApps Technologies+2netguru.com+2

• Picasso is another widely used library. netguru.com+3GeeksforGeeks+3RipenApps Technologies+3

• Coil is a newer, Kotlin-first image loader (built on coroutines); worth mentioning as a modern alternative even if not always in “top lists” yet. (You may want to check current usage stats).

• Why include: image loading is ubiquitous; choosing the right one can have big performance impact.

7. RxJava / RxAndroid / Reactive Libraries

• Though coroutines + Flow are the modern path, RxJava / RxAndroid still have a large codebase, many existing projects, and are worthy of mention. RipenApps Technologies+2Auxano Global Services+2

• Useful for composition of multiple asynchronous streams, operators, backpressure, etc.

• If your audience includes those maintaining legacy systems, still relevant.

8. Utility / Helper / Toolkit Libraries

These are “boring but useful” libraries that can make life easier.

• Google Guava – For extended collections, caching, utilities, immutable types, etc. Wikipedia

• Timber – Logging library that’s better than Android’s default Log (tagging, tree planting)

• kotlinx-serialization – For JSON / data serialization in Kotlin

• Moshi / Gson – JSON (de)serialization – Moshi is more modern / safer; Gson is very widespread

• ThreeTenABP / java.time backports – For date/time operations in Android (depending on min SDK)

• AndroidX / Jetpack libraries: Lifecycle, Navigation Component, Paging, WorkManager, DataStore, SplashScreen API, etc. These are extensions built or endorsed by Google / Android team. A3Logics+2MoldStud+2

• Stetho – Debugging bridge by Meta — allows inspection of network, DB, view hierarchy via Chrome DevTools. GeeksforGeeks+1

• LeakCanary – Memory-leak detection library (often cited in Android blogs)

• Chucker / Chuck – HTTP debugging / intercepting library (intercepts network and shows HTTP requests/responses in UI)

9. Charts, Animations, Visualization

• MPAndroidChart – For charts (bar, line, pie, radar, etc.) and data visualization. netguru.com+1

• Lottie – For animations (JSON-driven, vector animations)

• MotionLayout / ConstraintLayout / Animations – While not a third-party library per se, it's good to mention modern Android animation & layout tools (and how third-party libs complement them)

• AnimatedPieView, etc. (some blogs mention them) netguru.com

10. Testing & Mocking Libraries

• JUnit / AndroidX Test – Core test frameworks

• Mockito / MockK – For mocking dependencies

• Espresso / Compose UI Testing – For UI / integration tests

• Robolectric – Local unit tests for Android APIs

• Turbine – For testing Kotlin Flow streams

• Koin test / Koin mock modules (if you include Koin)

11. Other Emerging / Honorable Mentions

• Libraries around modularization, plugin architecture, feature flagging, in-app update, dynamic feature modules

• AR/VR / ML / camera / media libs (e.g. ML Kit, CameraX)

• Compose Multiplatform (if you want to mention cross-platform UI reuse)

• GraphQL clients (Apollo for Android)

• Coroutines + Paging + Remote Mediator (for hybrid remote+local pagination)