Differences between Web API and REST API

Let’s look at some of the differences between Web API and REST API in this tutorial.

What is a Web API?

A Web API is an API that works over the web using the HTTP or HTTPS protocol.
It allows one application (like a mobile app, web app, or another server) to communicate with another
application over the internet.

Think of a Web API as:

• A general way for software to talk to each other using web technologies.
• It can follow different styles or standards, such as REST, SOAP, GraphQL, etc.
• It is not limited to one specific design pattern.

Examples:

• An API that returns weather data when your app sends a request.
• An API that lets you log in using Google or Facebook.

What is a REST API?

A REST API (Representational State Transfer API) is a specific type of Web API
that follows a set of rules called the REST architectural style.

REST APIs usually:

• Use standard HTTP methods like GET, POST, PUT, DELETE.
• Work with resources (such as users, products, orders) that are identified by URLs.
• Often use data formats like JSON (very common) or XML.

Think of a REST API as:

• A specific way of designing a Web API.
• A Web API that follows REST rules and principles.

Differences between Web API and REST API

	Web API	REST API
Basic Definition	An API that works over the web using HTTP/HTTPS.	A Web API that follows the REST architectural style.
Scope	Broad term: includes REST, SOAP, GraphQL, and other patterns.	Narrower term: one specific style of building Web APIs.
Design Style	Can use any design: REST, SOAP, RPC, GraphQL, custom designs, etc.	Must follow REST principles such as statelessness, resource-based URLs, and use of HTTP methods.
Use of HTTP Methods	May or may not use HTTP methods in a standard way.	Strongly relies on standard HTTP methods like GET, POST, PUT, DELETE to represent actions.
Resources and URLs	Structure of URLs is flexible and can be designed in many ways.	Focuses on resources (like /users, /products) with clear, consistent URLs.
Data Formats	Can use various formats: JSON, XML, HTML, plain text, etc.	Commonly uses JSON or XML, with JSON being the most popular.
Standards and Rules	No single strict set of rules; depends on the chosen style (REST, SOAP, etc.).	Follows REST constraints such as client-server, stateless communication, cacheable responses, and layered system.
Relationship	“Web API” is the bigger category.	“REST API” is a type of Web API within that category.
Typical Use Cases	Any web-based communication: payments, authentication, third-party integrations, etc.	Modern web and mobile app backends, microservices, public APIs (like social media APIs).
Example	An API that uses SOAP XML messages over HTTP is still a Web API but not REST.	An API where GET /users returns a list of users in JSON format, and POST /users creates a new user.

In general:

Every REST API is a Web API, but not every Web API is a REST API.
Web API is a broad category; REST API is a specific style inside that category.

• Web API: Any API that works over the web using HTTP/HTTPS.
• REST API: A Web API that follows REST rules and uses HTTP in a structured, resource-focused way.