Instant messaging application with + 50k user

[umtblbl]

Hi friends, I want to do messaging app on android studio. For example, if we think of a platform where instant users can instant messaging 50k, can we use firebas for this? or socket io or what can be used? We know that security, accessibility, robustness are important issues.

- Can you give advice on this?
- I would be very happy if you send a video, sample document of interest to your advice.

Please help, thank you, good work.