I’m working on an app and websites. They have related information such as users, contracts, etc. What is the reason for designing an API and not connecting directly to the database?
Edit:
I’m just starting development and have no experience with web services. Please be as thorough as possible.
Sites such as Facebook, Google, and Twitter could never let third party apps connect directly to their database: it’s an enormous security risk. (Would you be comfortable if Facebook allowed anyone to access their database, including private user information and messages?)
APIs serve as a gate through which third party apps can get the kinds of information they are permitted to access.