Since docker 1.8 you can see that:
This API is deprecated as of 1.7. To view the old version, see the Docker Hub API in the 1.7 documentation.
But when I look at the new documentation There is nothing about the API access.
I thought it was based on Docker Trusted Registry but I can't make it work.
Commands like that works: curl -k https://registry.hub.docker.com/v1/repositories/ubuntu/tags
but it's v1 deprecated api.
V1 is deprecated. You can find the latest documentation here: https://docs.docker.com/registry/spec/api/
Here is a couple of example scripts using the api:
For a user account: https://gist.github.com/kizbitz/e59f95f7557b4bbb8bf2
For an organization account: https://gist.github.com/kizbitz/175be06d0fbbb39bc9bfa6c0cb0d4721