Coursier

Coursier is an open-source tool for dependency management and artifact retrieval in the JVM ecosystem, with a strong focus on Scala. It resolves, downloads, and caches libraries and applications from repositories such as Maven Central and other remote or local sources, providing a fast and reliable alternative to traditional resolvers.

At its core, Coursier performs dependency resolution, handles cross-versioning for Scala libraries, and downloads artifacts into a local cache. It supports multiple repository formats (Maven-compatible), parallel downloads, and reproducible builds by recording exact artifact coordinates and metadata. The cache design aims to improve repeat builds and reduce network overhead.

The tool can be used as a standalone command-line utility or embedded as a library within Scala or Java projects. It offers commands to fetch dependencies and launch applications with their dependencies, and it integrates with common tooling in the Scala ecosystem, including sbt and Ammonite, to streamline dependency management and script execution.

Coursier is maintained by the Scala community as an open-source project with contributions from individuals and organizations. It runs on major platforms, including Linux, macOS, and Windows, and is designed to be lightweight and fast across environments. The project emphasizes compatibility with existing Maven and Ivy repositories while delivering improved performance and more predictable dependency resolution.

In addition to its role in the Scala ecosystem, the term coursier is the French word for a courier or messenger, which explains the choice of name for this software project.