opencontainers/distribution-spec

The OCI Distribution Specification is a standardized API protocol that defines how to distribute container images and other content across registries and clients.

The specification addresses the need for a common, interoperable mechanism to push, pull, and manage container artifacts. It defines a REST API protocol that enables registries to store and serve container images and other content types in a standardized way. The approach is content-agnostic by design: while it fully supports the OCI Image Format Specification (which defines manifests, layers, and configuration), the distribution protocol itself can handle any type of artifact so long as it references the underlying blobs that comprise it. This flexibility allows the same distribution mechanism to serve container images, Helm charts, and other artifact types.

Adopters should understand that this specification is foundational infrastructure for container ecosystems. It is most relevant for teams building or operating container registries, implementing registry clients, or creating tools that need to interact with standardized distribution APIs. The specification works in concert with the OCI Image Format Specification and OCI Runtime Specification; if you are building container tooling that needs to fetch or store images in a standards-compliant way, this defines the protocol you will implement. The project provides Go types for working with the specification and conformance tooling to verify that registry implementations meet the standard.

The project maintains formal governance structures including contribution guidelines, a maintainers' guide, and a defined release process. Development is tracked through GitHub issues for bugs and actionable items, with longer discussions occurring on a mailing list. The specification includes an extensions process that allows for prototyping and testing new capabilities, with the expectation that extensions advance only with demonstrated support from registries, clients, and users. The Go types and validation tooling are maintained to be compatible with current Go releases.