What is REST vs API?

REST (Representational State Transfer) and API (Application Programming Interface) are related concepts, but they are not the same thing. Here’s a breakdown of their differences and how they relate to each other:

Definition

• API: An API is a set of rules and protocols that allow different software applications to communicate with each other. It defines the methods and data formats that applications can use to request and exchange information.

• REST: REST is an architectural style for designing networked applications. It is a specific way of implementing APIs, focusing on using standard HTTP methods and principles to enable stateless communication.

Key Differences

1. Scope:

   • API: Refers to any interface that allows software programs to interact. APIs can be built using various protocols, including REST, SOAP, GraphQL, and others.
   • REST: Specifically refers to APIs that adhere to the principles of REST architecture.

2. Communication Style:

   • API: Can use multiple protocols, such as HTTP, WebSockets, or FTP, for communication.
   • REST: Primarily uses HTTP and defines a set of constraints, such as statelessness, cacheability, and a uniform interface.

3. Data Format:

   • API: Can return data in various formats, including JSON, XML, or HTML, depending on how it’s designed.
   • REST: Most commonly uses JSON for data interchange, but it can also support XML and other formats.

4. State Management:

   • API: Can be stateful or stateless, depending on the implementation.
   • REST: Is always stateless, meaning each request from the client contains all the information the server needs to fulfill that request.

Examples

• REST API: A REST API for a bookstore might have endpoints like:
  • GET /books: Retrieves a list of books.
  • POST /books: Adds a new book.
• Other APIs: SOAP APIs or GraphQL APIs serve similar purposes but follow different protocols and principles.

Conclusion

While all REST APIs are APIs, not all APIs are RESTful. REST is a specific architectural style for creating APIs that emphasize scalability and stateless interactions. Understanding the differences between the two can help in designing and implementing effective web services.

For more detailed information, you can refer to:

• REST vs. API: What's the Difference? - Stack Overflow
• REST API Tutorial - RESTful API Basics
• API vs. REST: What's the Difference? - IBM