pubspecyaml

pubspec.yaml is a YAML manifest used by the Dart package manager (pub) and Flutter tooling to describe a project's metadata, dependencies, assets, and constraints. It resides at the root of a Dart or Flutter package or application and is parsed by the tooling to determine how to fetch dependencies and configure the project.

Key fields commonly found in pubspec.yaml include name, version, description, publish_to, environment, dependencies, dev_dependencies, dependency_overrides, and an optional flutter section for Flutter-specific resources. The name uniquely identifies the package, while version follows semantic versioning and may include a build number (for example, 1.0.0+1). The environment section specifies constraints on the Dart SDK, such as sdk: ">=2.12.0 <3.0.0". In Flutter projects, the flutter section can declare assets and fonts that should be bundled with the app.

Dependencies are listed under dependencies, and tools or testing libraries under dev_dependencies. Each entry pairs a package name with a version constraint, such as a caret specifier (for example, http: ^0.13.0). Dependency_overrides can be used to force specific versions when resolving conflicts.

The pubspec.yaml is used by commands like dart pub get or flutter pub get to fetch dependencies and generate a lock file (pubspec.lock) that records the resolved versions. The file is essential for reproducible builds and is typically versioned alongside the source code. In Flutter contexts, the pubspec may also reference assets (files included in the app bundle) and fonts required by the app’s UI.