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Dart provides a rich set of core libraries that offer essential functionality for common programming tasks. These libraries are automatically available to all Dart programs and provide the foundation for building robust applications.

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Library Categories

Dart’s core libraries can be grouped into several categories:

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Essential Libraries

dart:core - Automatically imported into every Dart program. Provides built-in types, collections, and other fundamental functionality. dart:async - Support for asynchronous programming with classes such as Future and Stream.

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Platform-Specific Libraries

dart:io - File, socket, HTTP, and other I/O support for non-web applications (servers, CLI apps, Flutter). dart:html - HTML elements and other resources for web-based applications.

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Specialized Libraries

dart:ffi - Foreign Function Interface for interoperability with the C programming language. dart:isolate - Concurrent programming using isolates: independent workers similar to threads.

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Platform Availability

Not all libraries are available on all platforms:
  • dart:io, dart:ffi, and dart:isolate are only available on Dart Native (VM, AOT, and Flutter)
  • dart:html is only available on web platforms
  • dart:core and dart:async are available on all platforms

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Import Syntax

Most core libraries need to be explicitly imported, except for dart:core which is automatically imported: 
// dart:core is automatically imported
// No import needed for String, int, List, etc.

// Other libraries must be imported
import 'dart:async';
import 'dart:io';
import 'dart:ffi';

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Common Use Cases

Asynchronous Operations

Use dart:async for Futures, Streams, and async/await patterns

File I/O

Use dart:io for reading/writing files and directories

Native Interop

Use dart:ffi for calling C libraries and native code

Parallel Execution

Use dart:isolate for CPU-intensive tasks in separate isolates

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Next Steps

Explore each library in detail:

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