In this chapter, we looked at some basic techniques to access data in popular text formats (TOML, JSON, and XML) or data managed by popular database managers (SQLite, PostgreSQL, and Redis). Of course, many other file formats and database managers exist, and there is still a lot to be learned about these formats and these database managers. Nevertheless, you should now have a grasp of what they do. These techniques are useful for many kinds of applications.
In the next chapter, we will learn how to build a web backend service using the REST architecture. To keep that chapter self-contained, we will only use a framework to receive and respond to web requests, and not use a database. Of course, that is quite unrealistic; but by combining those web techniques with the ones introduced in this chapter, you can build a real-world web service.