Been doing some deep diving in regards to building a backend for my flutter application. The premise and requirements I am looking for are something that is self-hosted and ultimately free (no monthly charges, overuse, etc like firebase) only the essentials such as storage that I would pay for IF AND ONLY IF required; in other words, it's my responsibility. I just downloaded MySql, my only question is how should I go about what APIs I could use for caching and passing data to the application, or do I even need a middleman to pass data? Input is much appreciated.