What do you have to know for one to start making chatting apps like fb/whatsapp, messanger and so on?

Question

What languages does one have to know

Answer 1

Learn html, css, js, php, mysql etc.
With prior knowledge of these languages, you can make these apps.

Check out this code written by a community member.
(WhatsApp)
https://code.sololearn.com/WCOniczTmYKQ/?ref=app

Answer 2

Thanks and it's a really cool code

Answer 3

it is difficult.
Also see this: https://www.freecodecamp.org/news/learn-how-to-use-react-and-graphql-to-make-a-full-stack-social-network/
Facebook uses

lnguages used: Hack, PHP (HHVM), Python, C++, Java, Erlang, D, XHP, Haskell