Central Authentication Service (CAS) allows users to use one set of credentials to sign in to many sites over many different protocols.
Rocket.Chat includes a CAS plugin that allows you to use your existing CAS server for user authentication.
For more information on CAS, see

Rocket.Chat CAS Administration

To access this setting, go to Administration > Settings > CAS.
Remember to hit Save Changes in order to apply any changes made.
Your Rocket.Chat instance is the CAS client. You must provide a compatible CAS Server.
Once you know your CAS server's URL, proceed with the settings.
The /cas and /cas/login URLs are the standard, but not required. Check with your CAS server provider if the defaults do not work.
  • Trust CAS username: When enabled, Rocket.Chat will trust that any username from CAS belongs to the same user on Rocket.Chat. This may be needed if a user is renamed on CAS, but may also allow people to take control of Rocket.Chat accounts by renaming their own CAS users.
  • Allow user creation: Allows CAS User creation from data provided by the CAS ticket when enabled.

Attribute Handling

  • Always Sync User Data: When set to true, it synchronizes external CAS User data into available attributes upon login. Note: Attributes are always synced upon account creation anyway.
  • Attribute Map: Use this JSON input to build internal attributes (key) from external attributes (value). External attribute names enclosed with '%' will be interpolated in value strings.
    Example, {"email":"%email%", "name":"%firstname%, %lastname%"}
    The attribute map is always interpolated. In CAS 1.0 only the username attribute is available. Available internal attributes are: username, name, email, rooms; rooms is a comma-separated list of rooms to join upon user creation e.g: {"rooms": "%team%,%department%"} would join CAS users on creation to their team and department channel.

CAS Login Layout

  • Login Popup Width: Lets you set the width in px of the popup screen during login.
  • Login Popup Height: This lets you set the popup height in px.
  • Login Button Label: Set the button's label.
  • Login Button Text Color: Sets the login button text color from existing variable.
  • Login Button Background Color: Sets the background color of the login button.
  • Autoclose Login Popup: When enabled, the popup will automatically close after authenticating.
After configuring, your registration and login pages will have the CAS button present.


  • CAS by ja-sig requires ssl/tls for all connections.
  • Any Drupal 7 or 8 sites can serve as a compatible CAS Server. See