buildpacks/spec

Cloud Native Buildpacks Specification is a formal specification that defines the interactions between platforms, lifecycles, buildpacks, and applications for transforming source code into OCI images and enabling automated testing.

The specification addresses the need for a standardized contract governing how buildpacks—software that transforms application source code into runnable artifacts—interact with lifecycles that orchestrate them and platforms that expose buildpack functionality to end users. It establishes precise requirements using RFC 2119 key words to ensure compliance, with explicit handling of operating system differences between Linux and Windows stacks, including path notation conventions and shell requirements.

Organizations building container platforms, buildpack implementations, or tools that integrate with Cloud Native Buildpacks should adopt this specification as the authoritative reference. It suits projects that need to ensure interoperability across different buildpack ecosystems or that are implementing platform, lifecycle, or buildpack components. The specification covers the Buildpack Interface, Platform Interface, Distribution, and several extensions including Bindings, Buildpack Registry, and Project Descriptor specifications.

The project maintains active development with regular updates to specification documents and extensions. Contributions flow steadily across multiple specification sections, indicating ongoing refinement of the standard. The maintainers engage with issues and pull requests addressing clarifications and enhancements to the specification language and requirements. The project tracks API versions explicitly, suggesting careful attention to backward compatibility and versioning practices.