How secure is firebase authentication?

The short answer is yes: by authenticating your users and writing security rules, you can fully restrict read / write access to your Firebase data . In a nutshell, Firebase security is enforced by server-side rules, that you author, and govern read or write access to given paths in your Firebase data tree.

Read more

Is Firebase authentication free?

All other Firebase Auth features are no-cost on all plans . Prices are per successful verification. On the Blaze plan, Phone Authentication provides a no-cost tier. The first 10K verifications for both instances (USA, Canada, and India and All other countries) are provided at no cost each month.

Read more