REST API Interview Questions and Answers

Here are the few commonly asked Interview Questions and Answers on RESTful web services.

REST API Interview Questions:

Q. What is REST and RESTful web service?

A. REST stands for Representational state transfer which is an architectural style for creating web service using HTTP (or) HTTPS protocol.

RESTful is referred to as a web service written by applying REST architectural concepts. In RESTful web service, HTTP methods GET, POST, PUT and DELETE are used to perform CRUD operations.

Q. What are the HTTP methods supported by REST?

GET: It requests resources at the request URL. This is a read-only operation.

POST: This operation is used to create a new resource or update an existing resource.

PUT: It requests for updating or modify the resource.

DELETE: This request is used to delete the resource on the server.

OPTIONS: This request fetches the list of options of resources available on the server.

HEAD: This request URL returns meta information.

Q. What are the characteristics of REST?

A. Stateless - REST API is stateless which means the server doesn't maintain any state so, each request is treated as a new request.

Q. What is URI?

A. URI stands for Uniform Resource Identification. Every resource in a REST architecture is identified by its URI.

In REST web service URI is used t locate resources on the server host.

Q. What are JAX-WS and JAX-RS?

A. Both JAX-WS and JAX-RS are libraries or APIs used to provide communication in various ways in Java.

JAX-WS is a library used to create SOAP communication in Java. JAX-RS is a library to create REST communication in Java.

Q. What are the tools used for testing Web services?

SOAP UI
Postman
Poster from Firefox web browser

Q. What is the difference between REST and SOAP?

SOAP stands for Simple Object Access Protocol.
REST stands for Representational state transfer.
SOAP is protocol.
REST is an architectural style.
SOAP permits the only XML.
REST supports many data formats such as XML, JSON, and HTML
SOAP slower than REST.
REST is faster than SOAP.

Q. What are the advantages of REST API?
REST API offers several advantages over traditional SOAP-based APIs. These include:

• Scalability – REST API enables us to scale our application easily without having to change any code.

• Flexibility – REST API is flexible enough to adapt to changing requirements.

• Performance – REST API is faster than SOAP.

Q. What is JSON?
JSON stands for JavaScript Object Notation. It is a lightweight text-based open standard designed to transmit data structures consisting of name/value pairs.

Q. What are the HTTP status codes?

A. HTTP status codes are the representation of the status of the task performed n the server which returns in the form of code. Each code has its meaning.