Problem statement
The Private Key JWT option is available for Machine to Machine Applications and Regular Web Applications, but the Credentials tab does not appear on Single Page Application (SPA) pages in the Dashboard.
Solution
Private Key JWT authentication is only available for Machine to Machine and Regular Web App application types since they will be authenticating via a backend call and not via the browser like a SPA. Since SPAs don’t authenticate via a Client Secret or Private Key JWT for that matter, this option is not applied to that app type.
Related References: