Docker, published here as the Moby Project, is the open-source collection of container toolkit components and the framework for assembling them into custom container-based systems, built for engineers, integrators and enthusiasts who want to modify, hack and build on container code rather than buy a commercially supported product.

What it is

Moby is an open-source project created by Docker to enable and accelerate software containerization. It lives in the container ecosystem and is written in Go, licensed under Apache-2.0, and maintained at the moby/moby repository with a project home at mobyproject.org. Its README describes it as a "Lego set" of toolkit components, the framework for assembling those components into custom container-based systems, and a place for container enthusiasts and professionals to experiment and exchange ideas. The components include container build tools, a container registry, orchestration tools and a runtime, all intended as building blocks that can be used alongside other tools and projects.

The concrete problem it solves is the gap between a fixed container product and the pieces needed to assemble one. Moby provides modular components with well-defined functions and APIs that work together, and its architecture keeps most of those components swappable for different implementations. It is also the upstream for the Docker product itself, while other projects are encouraged to use it as upstream and to reuse its components in diverse ways. For Go integrators, it additionally replaces a deprecated dependency: starting with Docker v29, released in November 2025, the Go module github.com/docker/docker is deprecated and no longer updated, and the supported public modules are now github.com/moby/moby/client and github.com/moby/moby/api.

Key capabilities

• Assembles container-based systems from toolkit components covering container build tools, a container registry, orchestration tools and a runtime.
• Keeps a modular architecture in which most components can be swapped for different implementations, described as "batteries included but swappable".
• Provides the Go client for the Docker Engine API as github.com/moby/moby/client.
• Provides API types shared between client and server as github.com/moby/moby/api.
• Ships the root module github.com/moby/moby/v2, which produces binaries only and is not intended to be imported as a Go library.
• Tags Docker Engine releases with a docker- prefix, for example docker-v29.0.0 for Docker Engine 29.0.0.
• Applies secure defaults without compromising usability, with APIs aimed at developers building powerful tools rather than at end users.

Who uses it and how

• Engineers, integrators and enthusiasts who want to modify, hack, fix, experiment, invent and build systems based on containers.
• Docker itself, which uses Moby as the upstream for the Docker product.
• External maintainers and contributors working on open source code, fixing bugs and making the code more useful.
• Other projects that reuse Moby components in diverse ways as their own upstream, with all such uses treated the same way.
• Developers building Go tooling around the Docker Engine API, who should depend on github.com/moby/moby/client and github.com/moby/moby/api rather than importing the root module.

Getting started

The entry point is the project home at mobyproject.org, and work starts from the root module github.com/moby/moby/v2, which is the codebase for building container engines based on Moby and produces binaries rather than a library to import. Releases built from that module are tagged with the docker- prefix, such as docker-v29.0.0.

How it compares

The README names Docker Desktop and Mirantis Container Runtime as the appropriate products for customers who want enterprise or commercial support, whereas Moby releases are supported by maintainers, community and users on a best-efforts basis only. Moby is therefore the open-source upstream for those commercial offerings rather than a supported product in its own right, and it explicitly is not the place to file support or feature requests for Docker products. Its Apache-2.0 licence and open contribution model contrast with the commercially supported route those two products represent.

When to use it — and when not to

Choose Moby if you intend to assemble, experiment with or contribute to container systems and accept operating the stack yourself, including whichever build, registry, orchestration and runtime components you select. Do not choose it if you need commercially supported software, vendor-backed support channels, or a stable Go library: the root github.com/moby/moby/v2 module carries no API stability guarantees, the old github.com/docker/docker module is deprecated and frozen as of Docker v29, and support is best-efforts. Go integrators should plan their dependency migration to github.com/moby/moby/client and github.com/moby/moby/api before writing new code against the engine API.

- import "github.com/docker/docker/client"
+ import "github.com/moby/moby/client"

- import "github.com/docker/docker/api/types"
+ import "github.com/moby/moby/api/types"