See the [GitHub SSH documentation](https://docs.github.com/en/authentication/connecting-to-github-with-ssh/about-ssh) for more details on how to configure SSH.
When using a GitHub personal access token, the username is arbitrary. GitHub does not support logging in with password directly, although other hosts may. If a username is provided without credentials, you will be prompted to enter them.
If there are no credentials present in the URL and authentication is needed, the [Git credential helper](https://git-scm.com/doc/credential-helpers) will be queried.
## HTTP authentication
uv supports credentials over HTTP when querying package registries.
Authentication can come from the following sources, in order of precedence:
- The URL, e.g., `https://<user>:<password>@<hostname>/...`
- A [`netrc`](https://everything.curl.dev/usingcurl/netrc) configuration file
- A [keyring](https://github.com/jaraco/keyring) provider (requires opt-in)
If authentication is found for a single net location (scheme, host, and port), it will be cached for the duration
of the command and used for other queries to that net location. Authentication is not cached across invocations of
uv.
Note `--keyring-provider subprocess` or `UV_KEYRING_PROVIDER=subprocess` must be provided to enable keyring-based
authentication.
Authentication may be used for hosts specified in the following contexts:
See the [alternative indexes integration guide](../guides/integration/alternative-indexes.md) for details on authentication with popular alternative Python package indexes.
