What is RESTful APIs?

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RESTful APIs (Representational State Transfer) are a set of architectural principles and conventions for designing and building web services. REST is an acronym for Representational State Transfer, which signifies the idea that resources (such as data entities) are represented and manipulated through the transfer of their representations over standard HTTP protocols.

Here are some key concepts and principles that define RESTful APIs:

  1. Resources:
    • Resources are the key entities that an API exposes. They represent the data entities or objects that clients can interact with.
    • Resources can be anything that can be uniquely identified, such as users, products, orders, or any other data entity within your application.
  2. Uniform Resource Identifiers (URIs):
    • Each resource in a RESTful API is identified by a unique URI (Uniform Resource Identifier).
    • URIs follow a hierarchical structure and provide a way for clients to locate and access specific resources.
  3. HTTP Verbs (Methods):
    • RESTful APIs use HTTP methods to perform different actions on resources.
    • Commonly used HTTP methods include:
      • GET: Retrieve a resource or a collection of resources.
      • POST: Create a new resource.
      • PUT: Update an existing resource.
      • DELETE: Remove a resource.
      • PATCH: Partially update a resource.
  4. Stateless Communication:
    • RESTful APIs are stateless, meaning that each request from a client to the server contains all the necessary information to process the request.
    • The server does not store any client-specific data between requests, which simplifies the scalability and reliability of the API.
  5. Representations:
    • RESTful APIs transfer resource representations between the client and the server. These representations can be in various formats, such as JSON, XML, or even HTML.
    • Clients can request a specific representation format by setting the appropriate Accept header in the HTTP request.
  6. Hypermedia as the Engine of Application State (HATEOAS):
    • HATEOAS is a principle of REST that encourages including hyperlinks in API responses, allowing clients to discover and navigate related resources dynamically.
    • Hyperlinks provide clients with the necessary information to interact with the API and discover available actions.
  7. Status Codes:
    • RESTful APIs use HTTP status codes to indicate the success or failure of a request.
    • Commonly used status codes include
      • 200 (OK),
      • 201 (Created),
      • 400 (Bad Request),
      • 404 (Not Found),
      • 500 (Internal Server Error).
  8. Versioning:
    • APIs can be versioned to allow for changes and updates without breaking existing client integrations.
    • Versioning can be done using URL paths, query parameters, or custom headers.

RESTful APIs provide a flexible and scalable way to expose data and functionality to clients over the web. By adhering to the REST principles, developers can create APIs that are easy to understand, consume, and maintain. The use of standard HTTP methods, resource representations, and status codes simplifies integration and enables interoperability between different systems.