All :doc:`build processes </builds>` have the following environment variables automatically defined and available for each build step:
.. envvar:: READTHEDOCS
Whether the build is running inside Read the Docs.
:Default: ``True``
.. envvar:: READTHEDOCS_VERSION
The :term:`slug` of the version being built, such as ``latest``, ``stable``,
or a branch name like ``feature-1234``. For :doc:`pull request builds </pull-requests>`,
the value will be the pull request number.
.. envvar:: READTHEDOCS_VERSION_NAME
The verbose name of the version being built, such as ``latest``, ``stable``,
or a branch name like ``feature/1234``.
.. envvar:: READTHEDOCS_VERSION_TYPE
The type of the version being built.
:Values: ``branch``, ``tag``, ``external`` (for :doc:`pull request builds </pull-requests>`), or ``unknown``
.. envvar:: READTHEDOCS_PROJECT
The :term:`slug` of the project being built. For example, ``my-example-project``.
.. envvar:: READTHEDOCS_LANGUAGE
The locale name, or the identifier for the locale, for the project being built.
This value comes from the project's configured language.
:Examples: ``en``, ``it``, ``de_AT``, ``es``, ``pt_BR``