What programming languages written in YouTube

I hope the sources prove useful to you. Happy coding!

https://www.quora.com/What-programming-languages-are-used-at-Youtube#:~:text=Initially%2C%20YouTube%20was%20developed%20in,therefore%20Python%2C%20Apache%20and%20MySQL.

https://www.quora.com/What-programming-languages-are-needed-to-make-YouTube

Python at the start.

Frontend: js Backend: c, cpp, py, Java, go