# Application-Specific OAuth Keys
It is important to note that there are some caveats when using custom OAuth keys for specific applications.
Certain services prohibit overlap in hostnames in callback urls used for the OAuth process. As such, you must configure specific CNAMES in DNS for each application that will use custom keys. The developer portal’s Custom OAuth Keys page provides the domain name that should be used for that application so that there is no conflict between applications using the Kloudless appliance.
For security purposes, some services require that the URLs used in the OAuth process are over HTTPS. This will require that the SSL certificates used by the appliance be valid for the hostnames used in the authentication process. A wildcard SSL certificate or the addition of subject alternative names to the certificate that is on the appliance will assist with this requirement.