Network Background

REST API vs. Web Services

Understanding the difference between the architectural style and the broader concept.
Is it a vehicle, or just the engine?

category The Big Picture

The most common misconception: They are not opposites.

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The Relationship

Web Services
REST API

Web Service is the superset (the umbrella term). It is any service available over the internet.

REST API is a specific architectural style of Web Service.

Rule of Thumb: All REST APIs are Web Services, but not all Web Services are REST APIs (e.g., SOAP).

language Web Service (The General Term)

A standardized way for two applications to communicate over a network. It can use various protocols (HTTP, SMTP, etc.) and formats (XML, JSON).
Commonly implies SOAP (Simple Object Access Protocol) in older enterprise contexts.

api REST API (The Modern Style)

REpresentational State Transfer. An architectural style that uses standard HTTP methods (GET, POST, PUT, DELETE) and lightweight formats like JSON. It focuses on resources.

compare_arrows Key Differences

Feature
api REST API
dns Web Service (SOAP*)
settings_ethernet Protocol
Strictly uses HTTP/HTTPS. It maps CRUD operations directly to HTTP verbs (GET, POST, etc.).
Protocol agnostic. Can work over HTTP, SMTP, TCP, JMS, etc. More flexible in transport.
code Data Format
Flexible. Supports JSON (most popular), XML, HTML, Plain Text, YAML. Lightweight parsing.
Rigid. Primarily uses XML. Requires complex parsing and larger bandwidth overhead.
memory State Management
Stateless. No server-side session info is stored between requests. Every request must contain all necessary info.
Can be Stateful or Stateless. SOAP was designed to handle complex transactions requiring state.
security Security
Relies on transport layer (HTTPS) and standards like OAuth 2.0 and JWT. Easier to implement for web.
Built-in WS-Security. Supports enterprise-level security features like ACID compliance and reliability.

* Note: "Web Service" here contrasts specifically with SOAP-based implementations, the traditional alternative to REST.

Which one should you choose?

Select your project requirement to see the recommended approach.