API

What is an API?

An API (Application Programming Interface) is a set of rules and tools that allows two or more computer programs to communicate with each other. Think of it as an intermediary layer between systems like a waiter taking your order (request) to the kitchen (server) and bringing back your food (response). It defines how communication happens (e.g., using HTTP/HTTPS protocols, GET or POST methods) and what data is exchanged.

APIs have evolved over time. Historically, the term described library or framework specifications, but today, when people say "API," they usually mean Web APIs, interfaces for web-based communication. Other types, like Web Socket APIs, exist too, but Web APIs dominate modern discussions.

What is an Interface?

An interface is the point of interaction between two systems or devices, enabling them to exchange information or signals. With APIs, this means you can communicate with a system without knowing its internal workings like how a server’s code or database is structured. The API handles the "how," shielding the complexity behind a clean boundary.

For example:

• Samsung Galaxy UI: The user interface (UI) connects you to your phone. You tap icons or swipe screens to interact, without needing to understand the phone’s internal software.
• Netflix: You enjoy dramas or movies without knowing how Netflix’s servers or databases are built. The interface (and its underlying APIs) makes it possible.

How APIs Work

APIs act as a middleman. When you use a browser to request something from a server (e.g., loading a webpage), the API processes that request and delivers the response. It also prevents direct access to the server’s database, adding a layer of security and control.

Take www.google.com as an example. The google is a mashup of data pulled from multiple API responses, search results, ads and so on, all coordinated behind the scenes.

Advantages of APIs

APIs offer benefits for both providers and users:

1. Security for Providers: You can expose only what you want such as specific data without revealing sensitive details (e.g., database structure, server constants).
2. Simplicity for Users: You get the data you need without worrying about how the service is built.
3. Efficiency with Open APIs: Public APIs (e.g., Google OAuth 2.0 API) streamline app development, saving time and money.
4. Flexibility: Internal changes (e.g., database tuning) don’t always require API updates, reducing the need for users to constantly update apps.
5. Data Aggregation: Providers can collect data centrally. Imagine running a bookstore like "Cham Book"—you could create an API to track visitor clicks or events (e.g., bestsellers or search trends at the website) and gather it all in one place.

Types of APIs

• Private APIs: Used internally or with trusted partners. Often, a hardcoded hash key secures server-to-server communication. For example, a company might share a secret key with a business partner for private data exchange.
• Public APIs: Open to everyone, but managed with limits like daily request caps (e.g.,  API restricts to 5000 calls per day) or per-account quotas to prevent overload.

Why APIs Matter

APIs are the backbone of modern software. They enable seamless integration, protect sensitive systems, and empower developers to build faster and smarter. Whether it’s powering a login system, aggregating user data, or serving up a webpage, APIs make the digital world tick quietly and efficiently.