We have some exciting news for Realtime Database developers on the Flame and Blaze plans: we're increasing your concurrent connections limit from 10,000 to 100,000!
Concurrent connections are the number of users simultaneously connected to your database. For context, it's useful to keep in mind that this number is generally one to three full orders of magnitude lower than your daily active users. To reach 100,000 concurrent users, you usually first need to accumulate tens of millions of daily actives.
Historically, we limited the concurrent connections to 10,000 per database. We requested that you reach out to us to raise this limit, which allowed us to do a quick verification of your app's health. We looked for things like unindexed queries or very heavy reads to make sure your app was ready to scale.
Recent improvements to our infrastructure have made it possible to increase that threshold to 100,000 concurrent connections (but you should still index your queries and never add listeners to the root path!). If you need to support even more concurrent connections, please contact us.
We're excited to bring this change to the Firebase Realtime Database. We've been working hard on improving scalability, and we hope this increase will make scaling more seamless for you. As usual, let us know if you have any questions or feedback. We're always excited to hear from you!