What is a Web API?

APIs, or Application Programming Interfaces, are powerful tools that simplify interactions between software systems by abstracting away the complex details of their inner workings. In this lesson, you'll focus on Web APIs, a specific type of API accessed over the internet.

By the end of this reading, you will understand the distinction between application APIs and web APIs and how web API servers expand on the functionality of traditional web servers.

Application API vs. Web API

APIs serve as bridges between software, allowing developers to interact with complex systems without needing to understand every underlying detail. They are like a restaurant menu—offering a list of items you can order (features) without needing to know how they are prepared in the kitchen (implementation).

For example, when you call Math.sin() in JavaScript, you don't need to understand the mathematical calculations involved. You only provide an angle as input and get its sine as the output. This abstraction makes programming more efficient by reducing cognitive load, enabling developers to focus on higher-level tasks.

Web APIs extend this principle to the internet. They allow developers to store, share, and update data over the web without worrying about the underlying infrastructure or implementation details.

Consider the GitHub REST API, which allows you to retrieve information about organizations or repositories. For instance, visiting https://api.github.com/orgs/appacademy returns basic details about App Academy's GitHub organization:

{
  "login": "appacademy",
  "id": 19602878,
  "url": "https://api.github.com/orgs/appacademy",
  "description": "Open-source projects from App Academy"
}

To retrieve this data, you don't need to know anything about GitHub's back-end architecture—whether they use MongoDB or SQL, Linux or Windows, or what programming languages power their infrastructure. All that matters is the API's documentation, which tells you how to structure your requests to get the data or perform the actions you need.

Traditional Server vs. Web API Server

Traditional web servers follow a simple model: a client sends a request for a specific resource (e.g., an HTML page or image), and the server responds with that resource or an error message. Think of this as ordering a dish at a restaurant—you request a specific item, and you either receive it or learn that it’s unavailable.

Web API servers, however, take this functionality to a new level. They are like libraries that not only provide books (resources) but also let you perform various operations, such as searching for titles, checking availability, or even reserving books.

Web APIs can provide complex operations far beyond retrieving static resources. For example:

• CRUD operations: APIs often use HTTP verbs like GET, POST, PUT, and DELETE to create, read, update, or delete data on a server.
• Advanced operations: Some APIs calculate routes between locations, facilitate cryptocurrency transactions, or search large databases of research papers.

This versatility is why web APIs have become the backbone of modern web development, enabling dynamic and interactive applications.

What You've Learned

In this lesson, you learned that:

• A web API is an API accessed over the internet, enabling developers to interact with remote systems without needing to understand their internal workings.
• Web APIs abstract complexity, just like traditional APIs, but operate over the web rather than through imported libraries.
• Web API servers expand on traditional web server functionality by supporting diverse operations, from basic CRUD actions to complex calculations and database searches.

With this foundation, you’re ready to explore how to use web APIs to build feature-rich, dynamic applications.