Dart Packages and pub.dev

What is pub.dev?

pub.dev is the official package repository for Dart and Flutter. It hosts thousands of community and official packages. The dart pub command manages packages — installing, updating, and removing dependencies.

pubspec.yaml

Every Dart project has a pubspec.yaml that declares metadata and dependencies:

name: my_dart_app
description: A sample Dart application
version: 1.0.0

environment:
  sdk: '>=3.0.0 <4.0.0'

dependencies:
  http: ^1.1.0
  intl: ^0.18.0
  path: ^1.8.0
  equatable: ^2.0.5

dev_dependencies:
  test: ^1.24.0
  lints: ^3.0.0

Adding Packages

# Add a dependency
dart pub add http

# Add a dev dependency
dart pub add --dev test

# Get all dependencies
dart pub get

# Update all to latest compatible:
dart pub upgrade

# Upgrade to potentially-breaking latest:
dart pub upgrade --major-versions

# Remove a package:
dart pub remove http

Popular Packages

Package	Purpose
http	HTTP requests
dio	Advanced HTTP with interceptors
intl	Internationalization, date formatting
path	Cross-platform file path manipulation
json_serializable	Code-gen for JSON models
freezed	Immutable classes, unions, copyWith
equatable	Value equality for classes
test	Dart testing framework
mockito	Mocking for tests
shelf	Dart HTTP server framework

Creating Your Own Package

# Create a new package:
dart create --template=package my_package

# Package structure:
# my_package/
#   lib/
#     my_package.dart        ← public API entry point
#     src/
#       feature_one.dart     ← internal implementation
#   test/
#     my_package_test.dart
#   pubspec.yaml
#   README.md
#   CHANGELOG.md

// lib/my_package.dart — export only public API
library my_package;

export 'src/string_utils.dart';
export 'src/math_utils.dart';

// lib/src/string_utils.dart
extension StringExtensions on String {
  String capitalize() => isEmpty ? this : '$${this[0].toUpperCase()}$${substring(1)}';
}

🧠 Quiz

Summary

pub.dev is Dart's package repository. Declare dependencies in pubspec.yaml and install with dart pub get. Use dart pub add <package> for quick installs. The ^ prefix means "compatible with this version". Create packages with dart create --template=package and expose your API via export in the library's entry point.