Jitsi Meet backend modification and adding custom logic

Hi,

I would like to customize Jitsi Meet back-end and add my custom logic like calling API for database interaction and charging each user for the call etc. Could you please where shall I update or look for the code for the back-end as I am unable to understand where shall I look for the backend code in the git repository?

I would also like to know where shall I look for the frontend code in the jitsi-meet github repository?

What you are looking for is a prosody module. Examples of currently implemented modules: https://github.com/jitsi/jitsi-meet/tree/master/resources/prosody-plugins
You can check speakerstats.

https://github.com/jitsi/jitsi-meet is the web and mobile source-code.