Ask HN: Authentication (Self or 3rd Party?)

Hey HN,

I have a new project that is a multi-tenant project and might one day use SSO, AD, Office365, etc.

So I'm wondering should I just code my own Authentication Service (microservice) within my infrastructure. Or should I deal with a 3rd Party IdP such as Auth0 or Stormpath?

Rest of my infrastructure will be microservices so a JSON Web Token will be the required token that gets passed in headers.