APIs allow different software systems to talk to each other, and every conversation starts with a request. Understanding how API requests work is essential for connecting applications, sharing data, and triggering actions across the web. In this chapter, you will learn what an API request is, why it matters, and how different request methods control what happens next.

When you interact with an API, you send requests that tell the system what you want to do. These requests use specific HTTP methods to communicate your intentions. The most common methods you will encounter are GET, POST, PUT, and DELETE. Each method has a clear purpose and represents a different kind of action.

A GET request is used when you want to retrieve information from an API. You are simply asking for data, like fetching a list of users or details about a specific product. The API responds by sending back the information you requested, but it does not change anything on the server.

If you need to add new data, you use a POST request. This method tells the API to create something new, such as submitting a new order or registering a new user. When you send a POST request, you often include some data in your request, and the API processes it to create the new resource.

When you want to update existing information, you use a PUT request. This method is designed for making changes to something that already exists, like updating a user's profile or changing the details of a product. The PUT request carries the updated data, and the API replaces the old information with the new version you provide.

Finally, if you need to remove something from the system, you use a DELETE request. This method tells the API to erase a specific resource, such as deleting a file or removing a user account. Once the API receives a valid DELETE request, it takes action to remove the specified item.

By choosing the right HTTP method for your request, you clearly communicate your intentions to the API, whether you are retrieving, adding, updating, or deleting data. Understanding how these methods work is essential for making effective API requests and building reliable integrations.

Practical Example: Using API Methods in an Application

Imagine you are using a to-do list application that connects to a server using an API. Here is how the application uses different HTTP methods to manage your tasks:

• GET: When you open the app, it sends a GET request to the API to fetch all your current tasks; this lets you see your to-do list.
• POST: When you add a new task, the app sends a POST request with the details of your new task to the API; the server saves this new task and adds it to your list.
• PUT: If you edit a task, such as changing its name or marking it as complete, the app sends a PUT request to the API with the updated information; the server updates the specific task.
• DELETE: When you remove a task from your list, the app sends a DELETE request to the API; the server deletes that task from your list.

Each method has a specific purpose: GET retrieves information, POST creates something new, PUT updates existing data, and DELETE removes data. This makes it easy for your application to manage your to-do list by communicating clearly with the API.