Where to start learning the backend?

Question

IT education

Good day to all, I am a middle front-end developer, specifically in the front-end for more than 3 years, I also had experience in writing telegram bots, simple apics and desktop applications on node.js, working with databases also did not bypass me. Now I plan to slowly roll into the backend in order to understand and be able to do basic things myself without resorting to third-party developers, for example, when writing api + authorization and registration and working with the database for SPA (One and a half years on vue, the type of activity is mainly related to with the creation of single page applications). So far I'm looking towards python, php and nodes, but I'm also ready to take into account other languages ​​like GO or Sharpe. If there are more or less qualified back-end developers here, please explain what would be better in my case, what literature can be read first,

Answer 1

First you need to choose a stack, and then study it.
Lots of quality material for complete beginners on Laravel, Django and Ruby on Rails, so you can start with some of them.
As a project, make some simple backend for your frontend, like a toaster clone with registration, questions, and comments.