Calling curl request as soon as register user is done

On the register screen, I want to register in Laravel's DB as well as in another application concurrently. So what I have been trying to do is to below the register user request, send a curl request to create user in the another app.

But this isnt working.

I am trying this with the php make:auth code itself and have not customized the auth code at all.

where should I fire the curl call so that the registration happens at exact same at both places.