For my database/backend, I am using PHP which resides in the folders of a website for a social media iOS app I am developing in Swift. I know the typical backend is Firebase (or something like this) but I want to know if the strategy I am currently using with PHP and a website is a suitable method for managing user data. I am looking for downsides of using PHP, and if it is secure to hold the data on a public web application database rather than in Firebase.
Security is not only linked to Firebase or not but on how your server is protected. PHP requests with SSL (https) can be pretty secure.
What is the "public web application database " ? Is it a database service hosted outside ? If so, its security should be checked.
There is no "typical" backend. Firebase only seems popular because so many people have problems with it and post about it. 😄 I strongly encourage looking at AWS. They have many, many solutions available. Many of them are low-cost or even free initially.