REST API vs. RESTful API
While the terms are often used interchangeably, there is a subtle distinction based on the level of adherence to REST principles.
1. REST API
REST API is a broad term for any API that uses the REST architectural style. * Core: If an API uses HTTP methods and defines resources via URIs, it is generally referred to as a REST API. * Reality: Many developers use this term to describe any API that exchanges JSON data over HTTP.
2. RESTful API
RESTful API refers to an API that strictly adheres to all the constraints and principles of REST. * Meaning: It is a descriptive term ("The API is RESTful"). * Requirement: Beyond just using HTTP, it must implement best practices like correct status codes, noun-based URIs, and ideally, HATEOAS.
3. Comparison Table
| Category | REST API | RESTful API |
|---|---|---|
| Definition | An API based on REST architecture. | An API that fully implements REST principles. |
| Focus | Technical implementation (HTTP + JSON). | Design consistency and best practices. |
| Strictness | Can be loosely applied. | Must satisfy all constraints. |
| Example | GET /update_user/1 (Contains verb). |
PATCH /users/1 (Correct structure). |
4. Why Strive for "RESTful" Design?
- Readability: The URI and method clearly communicate the intent without extra documentation.
- Scalability: Clearly separates client and server concerns for independent growth.
- Self-Descriptive: Standardizes the way resources are handled, making it easier for other developers to adopt.