Git Credential Manager (GCM) supports authentication with multiple different Git host providers including: GitHub, Bitbucket, and Azure Repos. As well as the hosted/cloud offerings, GCM can also work with the self-hosted or "on-premises" versions of these services: GitHub Enterprise Server, Bitbucket DC Server, and Azure DevOps Server (TFS).
By default, GCM will attempt to automatically detect which particular provider is behind the Git remote URL you're interacting with. For the cloud versions of the supported providers this is done by matching the hostname of the remote URL to the well-known hostnames of the services. For example "github.com" or "dev.azure.com".
In order to detect which host provider to use for a self-hosted instance, each provider can provide some heuristic matching of the hostname. For example any hostname that begins "github.*" will be matched to the GitHub host provider.
If a heuristic matches incorrectly, you can always explicitly configure GCM to use a particular provider.
In addition to heuristic matching, GCM will make a network call to the remote URL and inspect HTTP response headers to try and detect a self-hosted instance.
This network call is only performed if neither an exact nor fuzzy match by
hostname can be made. Only one HTTP HEAD call is made per credential request
received by Git. To avoid this network call, please
explicitly configure the host provider for your self-hosted
instance.
After a successful detection of the host provider, GCM will automatically set
the credential.provider configuration entry
for that remote to avoid needing to perform this expensive network call in
future requests.
You can control how long GCM will wait for a response to the remote network call
by setting the GCM_AUTODETECT_TIMEOUT environment
variable, or the credential.autoDetectTimeout
Git configuration setting to the maximum number of milliseconds to wait.
The default value is 2000 milliseconds (2 seconds). You can prevent the network call altogether by setting a zero or negative value, for example -1.
If the auto-detection mechanism fails to select the correct host provider, or if the remote probing network call is causing performance issues, you can configure GCM to always use a particular host provider, for a given remote URL.
You can either use the the GCM_PROVIDER environment variable,
or the credential.provider Git configuration setting
for this purpose.
For example to tell GCM to always use the GitHub host provider for the "ghe.example.com" hostname, you can run the following command:
git config --global credential.ghe.example.com.provider github