The Ultimate Guide to Famous Applications Written in Kotlin (& Why Top Developers Choose It)

In the dynamic world of software development, choosing the right programming language is a critical decision that can define a project's success. For years, Java was the undisputed king of Android development. Then, a modern, pragmatic language emerged and fundamentally changed the landscape. This guide explores the world of applications written in Kotlin, from its origins to its future, and showcases why it has become the preferred choice for developers building robust, scalable, and innovative software.

From Android Staple to Multiplatform Powerhouse: The Unstoppable Rise of Kotlin

Kotlin's journey began when JetBrains, the company behind powerful developer tools, unveiled it as a new statically-typed language running on the Java Virtual Machine (JVM). The goal was to solve common pain points developers faced with Java, offering a more concise, safer, and modern alternative without sacrificing the power and stability of the JVM ecosystem.

While it gained a dedicated following early on, the true turning point came during Google I/O when Google announced first-class support for Kotlin on Android. This endorsement was a monumental shift, signaling to the entire development community that Kotlin was not just a viable alternative, but the future of Android app development. Since then, its adoption has skyrocketed, with a majority of professional Android developers now using Kotlin to build their apps.

But the story doesn't end with Android. Kotlin's pragmatic design has propelled it beyond mobile, into the realms of backend development, web frontends, and, most excitingly, multiplatform projects. The rise of applications written in Kotlin is a testament to its versatility and power, cementing its status as a true multiplatform powerhouse.

The 'Why': 5 Core Reasons Top-Tier Apps are Built with Kotlin (Beyond the Hype)

Why have so many development teams embraced Kotlin? The reasons go far beyond just being the 'new thing'. It's about tangible benefits that improve code quality, developer productivity, and application performance.

1. Enhanced Safety and Reduced Errors

One of Kotlin's most celebrated features is its built-in null safety. The type system distinguishes between nullable and non-nullable references, forcing developers to handle potential nulls at compile time. This virtually eliminates the dreaded `NullPointerException`, one of the most common sources of crashes in Java-based applications. This focus on safety leads to more stable and reliable apps.

2. Concise and Readable Code

Kotlin is designed to be expressive and concise. It drastically reduces the amount of boilerplate code required compared to Java. Features like data classes, type inference, and smart casts allow developers to write less code to achieve the same result. This not only speeds up development but also makes the codebase easier to read, understand, and maintain.

3. 100% Interoperability with Java

Kotlin was designed with Java interoperability as a primary goal. You can have Kotlin and Java code side-by-side in the same project, and they can call each other seamlessly. This allows for a gradual and low-risk migration of existing Java projects to Kotlin. Teams can start writing new features in Kotlin while keeping their legacy Java code, leveraging the vast ecosystem of Java libraries and frameworks without issue.

What makes Kotlin a good choice for Android apps?

Kotlin is an excellent choice for Android apps because it is the official language recommended by Google. It offers enhanced safety by eliminating null pointer exceptions, more concise code for faster development, full interoperability with existing Java codebases, and modern features like coroutines for efficient background tasks.

4. Powerful Concurrency with Coroutines

Modern applications need to perform asynchronous operations like network requests or database access without freezing the user interface. Kotlin's coroutines provide a powerful yet simple way to manage concurrency. They simplify asynchronous programming, making complex background tasks easy to write and read, which is a significant improvement over traditional callback-based approaches.

5. A Rich and Mature Ecosystem

Backed by JetBrains and Google, Kotlin enjoys robust tooling support, including excellent IDE integration in Android Studio and IntelliJ IDEA. The community is large, active, and growing, providing a wealth of libraries, frameworks, and shared knowledge that accelerates development and helps solve complex problems.

Deep Dive: Famous Android Apps Written in Kotlin

The true measure of a language's success is in the quality of the applications built with it. The list of famous applications written in Kotlin is long and growing, featuring many of the apps you likely use every day. These companies have invested heavily in Kotlin, demonstrating its capability to power complex, high-scale products.

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  Google: Many of Google's own flagship apps, including Google Drive, Google Maps, and Google Home, are increasingly written in Kotlin.

  
  


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  Netflix: The streaming giant rebuilt its Android app's UI player with Kotlin, praising its conciseness and safety.

  
  


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  Trello: The popular project management tool was an early adopter and has a significant portion of its Android app written in Kotlin.

  
  


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  Pinterest: Pinterest was another early adopter, migrating its app from Java and seeing significant improvements in developer productivity.

  
  


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  Uber: Uber uses Kotlin extensively for internal tooling and for developing new features in its main rider and driver apps.

  
  


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  Slack: The communication platform leverages Kotlin in its Android application to ensure a stable and reliable user experience.

  
  

This is just a small sample, but it illustrates the trust that top technology companies place in Kotlin to deliver world-class experiences to millions of users.

Category Breakdown 1: Productivity & Collaboration - How Kotlin Boosts Stability and Feature Velocity

For productivity apps like Trello, Evernote, and Slack, reliability is non-negotiable. Users depend on these tools for their daily work, and any downtime or bug can cause significant disruption. Kotlin's safety features are a major asset here.

Trello, Evernote, and Slack

For these companies, migrating to Kotlin was a strategic move. The reduction in boilerplate code allows their development teams to ship new features faster—a key competitive advantage in the fast-moving productivity space. Trello's team noted that Kotlin made their code more readable and easier to reason about, which directly translates to fewer bugs and a more stable product. Similarly, Evernote's gradual migration allowed them to modernize their codebase without halting feature development, improving both the developer experience and the end-user product.

Category Breakdown 2: Content & Social Platforms - How Kotlin Creates Engaging User Experiences

Platforms like Pinterest, Coursera, and Netflix thrive on providing smooth, engaging, and visually rich user experiences. Performance is key. Laggy scrolling, slow-loading content, or app crashes can quickly lead to user churn. Many of the most successful applications written in Kotlin fall into this category.

Pinterest, Coursera, and Netflix

Pinterest was a pioneer in adopting Kotlin for its Android app, starting its migration even before Google's official announcement. The move paid off, leading to faster development cycles and a more robust application. For Netflix, rebuilding its complex video player UI in Kotlin allowed for a cleaner, more maintainable architecture. Coursera uses Kotlin to power its mobile learning platform, where a stable and intuitive interface is crucial for a positive learning outcome. These companies leverage Kotlin's modern features to build the highly performant and responsive UIs that users expect from top-tier e-commerce and content platforms.

How does Kotlin improve app security?

Kotlin improves app security primarily through its null-safe type system, which prevents null pointer exceptions, a common vulnerability. It also encourages the use of immutable variables (val), reducing the risk of unintended data modification. These features, combined with secure coding conventions, help build more robust and secure applications.

Category Breakdown 3: On-Demand & Lifestyle Services - How Kotlin Enables Scalable and Reliable Operations

On-demand services like Uber and lifestyle apps like Tinder operate at a massive scale, handling millions of real-time requests. For these applications, scalability, reliability, and operational efficiency are paramount.

Uber and Tinder

Uber utilizes Kotlin not just in its main apps but also for developing internal tools that manage its complex operations. The language's conciseness and safety help Uber's large development teams work more efficiently and reduce the likelihood of introducing bugs into their critical systems. Tinder's Android app, which has a massive user base, is another prime example of an application written in Kotlin. The team undertook a full migration from Java, citing cleaner code and improved developer happiness as major benefits that ultimately contribute to a better, more reliable product for its users.

The Game-Changer: A Spotlight on Kotlin Multiplatform (KMP) Applications

Perhaps the most exciting evolution in the Kotlin ecosystem is Kotlin Multiplatform (KMP). KMP takes Kotlin's 'write once, run anywhere' philosophy to a new level by allowing developers to share code across different platforms, including iOS, Android, desktop, web, and server-side.

What is Kotlin Multiplatform (KMP)?

Kotlin Multiplatform (KMP) is a feature of Kotlin that allows developers to write and share common code, such as business logic, data models, and networking, across multiple platforms like iOS, Android, and web. This reduces code duplication and ensures consistency while still allowing for native UI development on each platform.

Unlike other cross-platform frameworks that often dictate the UI layer, KMP focuses on sharing the non-UI parts of an application—the business logic, data handling, and network communication. This allows teams to write their core application logic once in common Kotlin and then build a fully native, no-compromise user interface for each platform (e.g., using SwiftUI for iOS and Jetpack Compose for Android). This approach offers the best of both worlds: shared logic for efficiency and native UI for the best possible user experience.

Case Study: Real-World Examples of KMP Sharing Code Between iOS, Android, and Beyond

KMP is no longer an experimental technology; it's being used in production by major companies to build sophisticated applications.

Philips Hue

The Philips Hue app for controlling smart lighting uses KMP to share the complex logic for device discovery, communication, and state management between its iOS and Android apps. This ensures that both apps behave identically when interacting with the lights and significantly reduces the development effort required to maintain two separate codebases for this logic.

McDonald's

The global fast-food chain's mobile app also leverages KMP. By sharing business logic across platforms, they can roll out new features and promotions consistently and quickly to both their iOS and Android user bases, which is crucial for their global marketing campaigns.

The business benefits are clear: faster time-to-market, reduced development and maintenance costs, fewer platform-specific bugs, and a more consistent user experience. This strategic approach to application development is why KMP is rapidly gaining traction.

More Than Mobile: Uncovering Companies Using Kotlin for Backend and Server-Side Development

While Kotlin is famous for mobile, its strengths translate perfectly to the backend. Running on the JVM, it can leverage the massive, battle-tested Java ecosystem for server-side development, including powerful frameworks like Spring and Jakarta EE.

Can Kotlin be used for more than just Android?

Yes, absolutely. Kotlin is a versatile, multiplatform language. Besides Android, it is widely used for server-side development with frameworks like Spring and Ktor. With Kotlin Multiplatform (KMP), it can also target iOS, web, and desktop, sharing code across all of them.

Frameworks like Spring Boot have embraced Kotlin, offering first-class support that makes building robust, high-performance microservices and web applications a breeze. Additionally, JetBrains has developed Ktor, a lightweight and flexible framework built from the ground up in Kotlin for creating asynchronous servers and clients. Companies like Google, Pivotal, and Atlassian use Kotlin in their backend services, benefiting from its conciseness, safety, and the performance of the JVM.

From the Trenches: What Developers Actually Say About Migrating to and Working with Kotlin

Beyond the corporate case studies, the sentiment from individual developers in the community is overwhelmingly positive. The consensus is that working with Kotlin is simply more enjoyable and productive than working with older languages like Java.

Is it difficult to migrate a Java app to Kotlin?

No, it is not considered difficult. Thanks to Kotlin's 100% interoperability with Java and excellent tooling, migration can be done gradually. Developers can start writing new code in Kotlin within an existing Java project, and IDEs like Android Studio offer an automated Java-to-Kotlin converter to streamline the process.

Key themes that emerge from developer testimonials include a significant reduction in boilerplate code, appreciation for null safety, and the power of coroutines. Many Java developers report that the learning curve is gentle, and they become productive in Kotlin within a few weeks. The ability to write cleaner, more expressive code not only speeds up development but also boosts morale and job satisfaction. The existence of so many successful applications written in Kotlin serves as powerful social proof for teams considering the switch.

The Future is Kotlin: What's Next with Compose Multiplatform, WASM, and AI

Kotlin's evolution is far from over. The ecosystem is continuously innovating, pushing the boundaries of what's possible in software development.

Compose Multiplatform

Building on the success of Jetpack Compose for Android, Compose Multiplatform extends Kotlin's declarative UI framework to the desktop (Windows, macOS, Linux) and web. This allows developers to share not only their business logic but also their UI code across multiple platforms, enabling the creation of truly cross-platform applications from a single codebase.

Kotlin/WASM (WebAssembly)

Kotlin/WASM is an emerging technology that will allow developers to run their Kotlin code directly in the browser at near-native speed. This opens up new possibilities for building rich, high-performance web applications and sharing code between the server, mobile apps, and the web frontend.

What is the future of Kotlin development?

The future of Kotlin is multiplatform. With technologies like Compose Multiplatform for sharing UI and Kotlin/WASM for web applications, it is expanding beyond Android and the backend. Its role in data science and AI is also growing, positioning Kotlin as a versatile language for a wide range of future development needs.

Kotlin and AI

With its strong typing, performance, and JVM interoperability, Kotlin is also becoming an attractive option for data science and machine learning applications. Libraries for numerical computing and deep learning are maturing, making Kotlin a viable language for the entire data pipeline, from data processing to model deployment. This positions Kotlin as a key player in the future of AI development.

Your Partner in Modern Application Development

From its roots as a better Java to its current status as a multiplatform powerhouse, Kotlin has proven its value across the board. The sheer number and quality of applications written in Kotlin by the world's leading tech companies is a clear indicator of its power, reliability, and efficiency. Whether you're building a native Android app, a high-performance backend, or a next-generation multiplatform experience, Kotlin provides the tools to build better software, faster.

Navigating the transition to a new technology or leveraging its most advanced features requires expertise. At Createbytes, we specialize in building modern, scalable, and robust applications using cutting-edge technologies like Kotlin. If you're ready to unlock the benefits of Kotlin for your next project, contact us today to see how our expert team can help you succeed.