A Representational State Transfer (REST) API, commonly referred to as RESTful API or simply REST API, is an architectural style for designing networked applications. It is based on principles that emphasize a stateless client-server communication model, uniform resource identifiers (URIs) for resource identification, and standard HTTP methods (GET, POST, PUT, DELETE) for performing operations on resources.
Here are key components and characteristics of a REST API:
Resources
In a REST API, resources represent entities or objects that the client interacts with. Resources are typically identified by URIs, and each resource may have one or more representations (e.g., JSON, XML) that clients can retrieve or manipulate.
HTTP Methods
REST APIs use standard HTTP methods to perform operations on resources. These methods include:
- GET: Retrieve a representation of a resource.
- POST: Create a new resource.
- PUT: Update an existing resource or create a new one if it doesn’t exist.
- DELETE: Remove a resource.
- PATCH: Partially update a resource.
- OPTIONS: Retrieve information about the communication options available for a resource.
Stateless Communication
RESTful interactions are stateless, meaning each request from the client to the server contains all necessary information to fulfill the request. The server does not store any client state between requests, which simplifies scalability and reliability.
Uniform Interface
REST APIs use a uniform interface between clients and servers, promoting simplicity and decoupling between components. This includes using standard HTTP methods, resource identifiers (URIs), and representations (e.g., JSON, XML).
Representation
Resources are represented in a format such as JSON or XML, which clients can parse and interpret. Clients and servers can negotiate the representation format using content negotiation mechanisms provided by HTTP.
Statelessness
REST APIs are stateless, meaning each request from a client to the server must contain all the information necessary to understand and fulfill the request. The server does not store any client state between requests, which improves scalability and reliability.
REST APIs are widely used for building web services and web applications due to their simplicity, scalability, and compatibility with existing web standards. They enable interoperability between different systems and platforms, making it easier to integrate and communicate between disparate software components.