Channels

What is a "channel"?

Channels are locations where conda packages are stored. A channel can be a public package repository, a private or internal package repository, or a local directory on your computer.

Conda packages are downloaded from channels, which are URLs or channel names that point to directories containing conda packages. The conda command searches a configured set of channels when you install, update, or search for packages.

By default, packages are automatically downloaded and updated from the default channel, which may require a paid license, as described in the repository terms of service. You can modify which channels conda searches. For details, see how to modify your channel lists.

Common public channels

Some commonly used public channels and multichannels include:

defaults

A built-in multichannel that includes Anaconda-hosted channels such as main, r, and msys2 under repo.anaconda.com.

main

The primary Anaconda-hosted channel under repo.anaconda.com. It contains many commonly used packages distributed by Anaconda.

conda-forge

A community-led channel with packages maintained by thousands of contributors. The conda-forge project provides a large collection of packages across many ecosystems.

bioconda

A community channel focused on bioinformatics packages. The Bioconda project is commonly used together with conda-forge.

You can browse public channels and search for packages on Anaconda.org.

Specifying channels when installing packages

From the command line, use --channel to search a specific channel:

$ conda install scipy --channel conda-forge

You may specify multiple channels by passing the argument multiple times:

$ conda install scipy --channel conda-forge --channel bioconda

Priority decreases from left to right: the first argument has higher priority than the second.

Use --override-channels to search only the specified channel or channels instead of any channels configured in .condarc. This also ignores conda's default channels.

$ conda search scipy --channel conda-forge --override-channels

In .condarc, use the channels key to configure the list of channels conda searches for packages.

Learn more about managing channels.

Local channels

A local channel is a channel stored on your own computer or on a shared filesystem. Local channels are useful when you are building your own packages, testing packages before publishing them, or maintaining packages for an internal workflow.

Local channels use the same channel layout as remote channels. They contain platform subdirectories such as linux-64, osx-64, win-64, and noarch. Each subdirectory contains package files and repository metadata.

To use a local channel, provide a file:// URL or path to the channel root. For example:

$ conda search --channel file:///opt/conda-channel --override-channels

For a step-by-step example of creating and indexing a local channel, see creating custom channels.