Platform API

The Platform specification defines the interface between the CNB lifecycle and a platform that runs it.


Buildpacks are stored on the filesystem as unarchived files such that:

  • Each top-level directory is a buildpack ID.
  • Each second-level directory is a buildpack version.


For security reasons, images built with platforms, such as pack, build and run as non-root users.

Stacks (deprecated)

A stack (deprecated) is the grouping together of the build and run base images, represented by a unique ID.

The build image is used to run the buildpack lifecycle, and the run image is the base image for the application image.

Further Reading

You can read the complete Platform API specification on Github.