Package naming conventions

To facilitate communication and documentation, conda observes the package naming conventions listed below.

Package name

The name of a package, without any reference to a particular version. Conda package names are normalized and they may contain only lowercase alpha characters, numeric digits, underscores, hyphens, or dots. In usage documentation, these are referred to by package_name.

Package version

A version number or string, often similar to X.Y or X.Y.Z, but it may take other forms as well.

Build string

An arbitrary string that identifies a particular build of a package for conda. It may contain suggestive mnemonics, but these are subject to change, and you should not rely on it or try to parse it for any specific information.

Canonical name

The package name, version, and build string joined together by hyphens---name-version-buildstring. In usage documentation, these are referred to by canonical_name.


Conda package filenames are canonical names, plus the suffix .tar.bz2 or .conda.

The following figure compares a canonical name to a filename:


Conda package naming

Conda supports both .conda and .tar.bz2 package extensions. The .conda format is generally smaller and more efficient than .tar.bz2 packages. Read our blog post about it to learn more.

The build string is created as the package is built. Things that contribute to it are the variants specified either by the command line or the configuration from the conda_build_config.yaml, and the build number in the recipe. If there are no variants, then the build string is the build number that is specified in the recipe.

Package specification

A package name together with a package version---which may be partial or absent---joined by an equal sign.


  • python=2.7.3

  • python=2.7

  • python

In usage documentation, these are referred to by package_spec.