[skylark]

This is a tough question to answer. What constitutes "back end" has changed significantly over the last 5-10 years - an Amazon AWS infrastructure engineer does vastly different day to day work from a small startup engineer.

For you specifically, I'd recommend picking up a web development framework like Ruby on Rails. It will teach you every aspect of building websites: Interacting with databases, writing server endpoints, creating front end web pages, user authentication, deployment, and probably version control. I would consider all of these things to be the bread and butter of typical "back end" engineers (except for maybe the front end stuff.)

From there, you can broaden your knowledge in any direction that interests you. If you like building interactive applications, you can look into front end frameworks like React or Vue. If you want to focus more on back end, you can learn more about relational databases (Head First SQL is a great beginner resource.) Lots of directions you can go.

[collyw]

Agreed, for me learning Django covered a very broad area with and pointed me in the right direction regarding best practices. Deploying it is difficult enough that you will need to learn a about servers (its not desperately difficult but you will need to understand various things to get it running). I would suggest making a point of learning SQL properly understanding how to optimize queries.