There are multiple options to whitelist the ControlCase API gateway URL.

Option 1: Either by using cloud-based egress solution like Aviatrix

Option 2: By using firewall URL filtering

Option 3: Whitelist the IP addresses

  Region     API URL     IP addresses to whitelist  
  Non Europe     https://cs-api.controlcase.com     15.197.241.9 and 3.33.223.174  
  Europe (EU) region     https://cs-api-eu.controlcase.com     52.223.39.39 and 35.71.157.167  

Option 4: Open the outbound TCP/443 to any