APIKey without an AuthRepository

My Servicestack implementation doesn’t use an AuthRepository (maybe because it’s so old?. not sure). It looks like API Keys are heavily integrated with having an IAuthRepository. Is there an easy was to accept API Keys without one?

No it requires an AuthRepository that implements IManageApiKeys. You may want to instead look at using JWT Auth Provider and generate a long-lived JWT Token to use instead of an API Key.