How many users can Firebase handle for free?

Firebase Realtime Database is not completely free . There are certain pricing plans. If you want your app to scale you’ll need to pay for the number of connections, disk usage and network usage.

Firebase Hosting works out-of-the-box with Firebase services, including Cloud Functions, Authentication, Realtime Database, Cloud Firestore, and Cloud Messaging. You can build powerful microservices and web apps using these complementary Firebase services.

Firebase has three plans, one of them is free called Spark Plan. Using this free plan you can have only 100 active users at once , only 10GB data to be transferred within one month and store only 1 GB of your data.22 Oca 2018