Webservices API Testing

What is an API?

API is means Application Programming Interface.
It enables communication and data exchange between two separate software systems. 
A software system implementing an API contains functions/sub-routines which can be executed by another software system.

What is API testing?

API Testing is entirely different from GUI Testing and mainly concentrates on the business logic layer of the software architecture. This testing won't concentrate on the look and feel of an application.
Instead of using standard user inputs(keyboard) and outputs, in API Testing, you use software to send calls to the API, get output, and note down the system's response.
API Testing requires an application to interact with API. In order to test an API, you will need to 
Use Testing Tool to drive the API 
Write your own code to test the API

What is Web Service?

Web Service available over the web which Enables communication between applications over the web,
Provides a standard protocol/format for communication 

Why we use it?

Platform independent communication - using web services two different applications (implementation) can talk to each other and exchange data/information

Difference between API & Web service

Web Service is an API wrapped in HTTP.
All Web Services are API but APIs are not Web Services.
Web Service might not perform all the operations that an API would perform.
A Web Service needs a network while an API doesn't need a network for its operation.

What is WSDL?

WSDL stands for Web Services Description Language, an XML-based language that describes Web services and how to access and locate them.

What is UDDI?

UDDI stands for Universal Description, Discovery and Integration. It is an open, Internet-based specification that offers directory service for storing information about web services.

Types of Web Services

There are mainly two types of web services.

  • SOAP web services. (Simple Object Access Protocol) 
  • RESTful web services. (Representational State Transfer)

SOAP (Simple Object Access Protocol) – SOAP is a protocol which was designed before REST and came into the picture. The main idea behind designing SOAP was to ensure that programs built on different platforms and programming languages could exchange data in an easy manner.

REST – This was designed specifically for working with components such as media components, files, or even objects on a particular hardware device. Any web service that is defined on the principles of REST can be called a RestFul web service. A Restful service would use the normal HTTP verbs of GET, POST, PUT and DELETE for working with the required components.


What Is HTTP?
HTTP stands for Hypertext Transfer Protocol. At it’s most basic, it allows for the communication between different systems. It’s most commonly used to transfer data from a web server to a browser in order to allow users to view web pages. It’s the protocol that was used for basically all early websites.

What Is HTTPS?
HTTPS stands for Hypertext Transfer Protocol Secure. The problem with the regular HTTP protocol is that the information that flows from server to browser is not encrypted, which means it can be easily stolen. HTTPS protocols remedy this by using an SSL (secure sockets layer) certificate, which helps create a secure encrypted connection between the server and the browser, thereby protecting potentially sensitive information from being stolen as its transferred between the server and the browser.