Answer 1

Similar posts available use search bar before posting ur question

Hope it may helps u

https://www.sololearn.com/discuss/23112/?ref=app
https://www.sololearn.com/discuss/1189376/?ref=app
https://www.sololearn.com/discuss/1023936/?ref=app
https://www.sololearn.com/discuss/1169128/?ref=app
https://www.sololearn.com/discuss/775155/?ref=app

Answer 2

Python, Java, Erlang, PHP, Haskell , C++

Answer 3

Java

Answer 4

(html,css,js,xml),Java,python and database(sql)

Answer 5

Facebook use html, css, python, javascript, php, SQL, C++, GraphQl
, Perl, Erlang, Cocoa, Ruby and Java.
Basically the idea is; every vast application or website developer uses frameworks for it's developement. Thus directly or indirectly they use a lot of language in building a single stuff.

Answer 6

No one specifically mentioning React and React Native?

Answer 7

JavaScript, Hack, PHP, Python, C++, Java, Erlang, D, Xhp, Haskell

Answer 8

Php .... But currently have added more languages

Answer 9

Php

Answer 10

Python, Java , C++ , Php

Answer 11

Python, php, java,c++ etc programming languages used in Facebook 👍

Answer 12

Php

Answer 13

Yeah but mostly I heard PHP