The Moby Project is an open-source initiative created by Docker to enable and accelerate software containerization. Written primarily in Go, it functions as a modular toolkit providing foundational components for building container-based systems. Rather than being a finished product, Moby operates as a "Lego set" of components including container build tools, a container registry, orchestration tools, and a runtime, designed to be assembled into custom systems and combined with other projects.
The project is explicitly targeted at engineers, integrators, and enthusiasts who want to modify, experiment with, and build systems based on containers. It is not intended for users seeking commercially supported systems but rather for developers who want to work directly with open source code. The Moby Project maintains strong architectural principles centered on modularity, flexibility, and developer focus. Its design philosophy emphasizes that components should have well-defined functions and APIs that work together, while most components remain swappable with alternative implementations. Security is built in as a default without compromising usability, and the APIs are designed to be functional and useful for developers building powerful tools rather than as end-user interfaces.
Moby maintains a specific relationship with Docker. The components and tools in the Moby Project originated as open source components that Docker and the community built for the Docker Product, and Docker is committed to using Moby as the upstream for Docker releases. However, the project welcomes other projects to use Moby as an upstream and reuse components in diverse ways. External maintainers and contributors are actively encouraged. Importantly, Moby is not intended as a location for support or feature requests for Docker products themselves, but rather as a collaborative space for contributors to work on open source code and fix bugs.
The project provides public Go modules for developers, including github.com/moby/moby/client for the Docker Engine API and github.com/moby/moby/api for shared API types. Starting with Docker v29 released in November 2025, the legacy github.com/docker/docker module is deprecated and no longer updated. The root module github.com/moby/moby/v2 contains the codebase for building container engines but is not intended for import as a Go library. Moby is licensed under the Apache License, Version 2.0, and use may be subject to certain restrictions by the United States and other governments.
