On 1 Feb 2017, at 12:50, Richard Jones <ra.jones@dpw.clara.co.uk> wrote:

On 01/02/2017 12:33, Daan Dawud wrote:
It is a set of tools to build Mobile and Web Apps. 

Please visit https://firebase.google.com/ for more information and in particular thier Authentication feature which is exactly what you need.

Best,

Daan

I assume he's referring to this:
    https://github.com/firebase/firebaseui-web/tree/master/demo


And as such had diddly squat to do with Dancer2 and or perl AFAICS

OTOH I think the OP needs to look at oauth

eg 

http://search.cpan.org/dist/Net-Facebook-Oauth2/README.pod

Clive