Kotlin is a modern programming language developed by JetBrains. It is fully interoperable with Java and can run on the Java Virtual Machine (JVM). Kotlin is designed to be concise, expressive, and safe. It offers many features and benefits over traditional programming languages, including null safety, type inference, and coroutines.

Some key features of Kotlin include:

1. Conciseness: Kotlin reduces boilerplate code compared to Java, making it more productive and easier to read and write.

2. Null safety: Kotlin provides built-in null safety features, minimizing the risk of null pointer exceptions.

3. Type inference: Kotlin has a strong static type system that allows it to infer types, reducing the need for explicit type declarations.

4. Interoperability: Kotlin can seamlessly interoperate with Java code, allowing developers to gradually migrate their codebases.

5. Coroutines: Kotlin introduces coroutines, which are lightweight threads that can suspend and resume execution. This greatly simplifies asynchronous programming and makes it more efficient.

6. Extension functions: Kotlin allows adding new functions to existing classes without modifying their source code, enabling easy code reuse and enhancing readability.

Kotlin has gained popularity among Android developers since it is officially supported as a programming language for Android development alongside Java. It is also widely used in backend development, web development, and more.

Overall, Kotlin offers a modern and powerful programming language that enables developers to write clean, concise, and safe code.