What areas should I master to become a backend developer?

Guys, I need to find a way to become a backend developer. What areas should I specialize in, which software languages should I know, at what level?

This is a comprehensive course for you to follow. Check out freeCodeCamp backend course to get started. https://www.freecodecamp.org/learn/back-end-development-and-apis/

There are multiple technologies used in backend now a days, most popular once are based on Python, JavaScript ( node.js ) etc old software still uses majority of Java and still there is demand for Java.

I suggest you go through the JD of companies you wish to work for or which are near to your place or region. ( linkedin jobs, stackoverflow jobs and other popular job sites etc )

Based on JD research you can take a call.

But now a days “Full Stack Engineers” are in demand. I would suggest learn JS so that you can contribute on both front as well backend.

If you search “backend software developer” in YT, there are quite a few good videos to guide you.

Joke : Backend developers think themself as higher caste people ( Indian caste system ) compared to Frontend developers.