API stands for Application Programming Interface. It’s a way for two software applications to talk to each other.
Picture: Two people exchanging a letter through a window. One is the “client,” the other the “server.”
Think of a restaurant. You (the client) don’t go into the kitchen. You look at the menu (the API documentation). You tell the waiter (the API request) what you want. The waiter tells the kitchen. The kitchen cooks. The waiter brings you your food (the API response).
Picture: A diagram: Client -> API Request -> Server -> API Response -> Client.
An API defines the rules of communication. It says: if you send me a request in this format, I will send you back a response in that format. APIs are everywhere. When you check the weather on your phone, an API call happens.
Picture: A JSON response in a browser showing weather data.
API development is building those servers and defining those rules. It’s a critical skill for backend developers and full-stack developers.
Picture: A code editor showing a simple API endpoint in Python or JavaScript.