REST API stands for Representational State Transfer Application Programming Interface. It's a standardized way for applications to communicate over the internet using HTTP methods. In a REST architecture, a client application sends HTTP requests to a server API, which processes the request and returns an appropriate response. This architectural style is widely used for building web services because it's simple, scalable, and uses standard web protocols.
REST APIs use standard HTTP methods to perform different operations on resources. The most common methods are: GET, which retrieves data from a resource without modifying it; POST, which creates a new resource; PUT, which updates an existing resource; and DELETE, which removes a resource. Each method corresponds to a specific type of operation, making the API intuitive to use. Resources in a REST API might represent entities like users, products, orders, or any other data that the API manages.
Let's look at a practical example of a REST API for managing users. Common endpoints include: GET /users to retrieve a list of all users, GET /users/{id} to get a specific user by their ID, POST /users to create a new user, PUT /users/{id} to update an existing user, and DELETE /users/{id} to remove a user. When you make a GET request to the /users endpoint, the API might return a JSON response containing user data, as shown in the example. This structured format makes it easy for applications to process the data.
REST APIs follow several key principles that make them effective for web services. First, they are stateless, meaning the server doesn't store any client state between requests - each request contains all the information needed to process it. Second, they are resource-based, where everything is treated as a resource identified by a unique URI. Third, responses can be cached to improve performance. Fourth, they provide a uniform interface with standardized methods for communication between clients and servers. These principles together make REST APIs scalable, reliable, and easy to understand.
To summarize what we've learned about REST APIs: They use standard HTTP methods like GET, POST, PUT, and DELETE to perform operations on resources. These resources are identified by unique URIs, such as /users/{id}. REST architecture follows key principles including statelessness, cacheability, and a uniform interface. REST APIs typically return data in structured formats like JSON or XML, making them easy to work with. Due to their simplicity and scalability, REST APIs are widely used for building web services and mobile application backends. Understanding REST APIs is essential for modern web development and system integration.