API references

Welcome to the Kotlin API References page. Here you'll find links to the API documentation for the official Kotlin libraries and tools.

• Standard library (stdlib)
  

  The Kotlin Standard library provides core functionality for Kotlin programming, including essential APIs such as collections, text and string processing, ranges, sequences, and more. It extends platform-specific APIs and provides a Kotlin-first API for working with them.

  GitHub kotlin
  

• Test library (kotlin.test)
  

  A multiplatform testing library that provides common testing annotations and utility functions. It supports integration with popular test frameworks on each platform and offers a unified testing experience across the Kotlin ecosystem.

  GitHub kotlin
  

• Coroutines (kotlinx.coroutines)
  

  A powerful library for asynchronous programming using Kotlin coroutines. It offers tools to support structured concurrency, asynchronous streams, synchronization primitives like mutexes and semaphores, testing, and more.

  GitHub kotlinx.coroutines
  

• Serialization (kotlinx.serialization)
  

  A multiplatform serialization library. It provides a type-safe, compile-time mechanism for converting Kotlin objects to and from a variety of formats such as JSON, CBOR, and Protocol Buffers.

  GitHub kotlinx.serialization
  

• Kotlin I/O library (kotlinx-io)
  

  A multiplatform library for low-level I/O operations. It defines abstractions for reading from and writing to binary streams and buffers, designed to be efficient and portable across all Kotlin platforms.

  GitHub kotlinx-io
  

• Date and time (kotlinx-datetime)
  

  A multiplatform library for calendar-based computations. It provides representations of date values and supports timezone-specific operations.

  GitHub kotlinx-datetime
  

• JVM Metadata (kotlin-metadata-jvm)
  

  A library for reading and writing Kotlin metadata stored in JVM class files. It is primarily used by tools such as annotation processors, static analyzers, and compiler plugins.

  GitHub kotlinx-metadata
  

• Kotlin Gradle plugins (kotlin-gradle-plugin)
  

  The Kotlin Gradle plugins for compiling, testing, and packaging Kotlin code. These plugins simplify JVM and multiplatform builds, manage dependencies, and integrate with IDEs and CI systems.

  GitHub kotlin-gradle-plugin
  

• Ktor
  

  A framework for building asynchronous clients and servers in connected systems using Kotlin. Ktor is designed for scalability and flexibility and is deeply integrated with coroutines for non-blocking I/O and structured concurrency.

  GitHub ktor