Is there a way to send the email verification email from my server ?
This is how it's done on the client:
authData.sendEmailVerification().then(function() {
Is there a way to do it on the server ?
firebaser here
To my surprise there currently is no option to send verification email from within the Admin SDK. I'd recommend you file a feature request.
What you can do from the Admin SDK is update a user profile to mark their email as verified. This allows you to take control of the entire verification flow if you want to, finishing with a call to admin.auth().updateUser(...)
(on Node.js, see the link for other supported languages).