Main differences between REST API and RESTful

November 26, 2025

Main differences between REST API and RESTful

I wanted to save the answer that I got from Perplexity AI when I was reviewing main differences between REST and RESTful:

The difference between REST API and RESTful API is subtle but important: A REST API follows some principles of REST (Representational State Transfer) architecture, while a RESTful API strictly adheres to all REST principles such as statelessness, client-server separation, cacheability, uniform interface, and layered system architecture. In essence, REST refers to the architectural style, and RESTful describes an API implementation that fully complies with this style.

Key REST principles that RESTful APIs follow include using HTTP methods explicitly (GET, POST, PUT, DELETE), stateless communication where each request contains all necessary information, resource-based URLs, representation of resources (e.g., JSON or XML), and support for caching for performance improvements. RESTful APIs provide scalable, fast, and flexible web services suitable for various platforms and programming languages.

To follow best practices for a RESTful approach:

· Use HTTP methods according to their defined purpose (GET for retrieval, POST for creation, PUT for updates, DELETE for removal).

· Design resource URIs logically and hierarchically.

· Make APIs stateless; do not store client context on the server between requests.

· Use standard HTTP response codes to indicate operation status.

· Support multiple content types through content negotiation (JSON is most common).

· Implement caching mechanisms where applicable to improve performance.

· Secure your API with authentication and authorization.

· Provide clear, consistent error messages.

By adhering to these principles and best practices, your API will be truly RESTful, standardized, and easier to maintain and understand. The terms "REST API" and "RESTful API" are often used interchangeably in practice, but RESTful implies stricter compliance.

This distinction and best practices are supported and elaborated by recent sources on RESTful API design.^[1]^[2]^[3]

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