Useful tools – Postman

Introduction

In today’s development world, the importance of APIs is known to almost all.

As mentioned in the previous topics, APIs make it possible for any two separate applications to transfer and share data between them. They also make it easier for an application’s users to execute actions without having to use the application’s GUI. From the developers’ POV, it’s an easy way to execute certain functionalities of their app and test it as well.

Using APIs on a daily basis might become cumbersome, as one might have dozens or even hundreds of APIs that he or she needs to use or test. That makes it difficult to keep up with their exact request’s address(es), header(s), authorization credential(s) etc., and that makes it harder to test the API for functionality, security and exception handling.

Learning Objectives

  • What is Postman
  • How to use it for testing your API

Study

What is Postman

Postman is an application used for API testing. It is an HTTP client that tests HTTP requests, utilizing a graphical user interface, through which we obtain different types of responses that need to be subsequently validated.

Methods

Postman offers many endpoint interaction methods. The following are some of the most used, including their functions:

  • GET: Obtain information
  • POST: Add information
  • PUT: Replace information
  • PATCH: Update certain information
  • DELETE: Delete information
Response Codes

When testing APIs with Postman, we usually obtain different response codes. Some of the most common include:

  • 100 Series > Temporal responses, for example, ‘102 Processing’.
  • 200 Series > Responses where the client accepts the request and the server processes it successfully, for instance, ‘200 Ok’.
  • 300 Series > Responses related to URL redirection, for example, ‘301 Moved Permanently.’
  • 400 Series > Client error responses, for instance, ‘400 Bad Request’.
  • 500 Series > Server error responses, for example, ‘500 Internal Server Error.’

How to use Postman

  • In case you don’t have Postman installed, you’ll need to download it and install it.
  • Once Postman is installed, you can launch it.
Postman three main parts

As you can see in the screenshot above, the Postman interface is separated into three main parts:

  • Saved requests / responses (Postman Collections)

  • The request editor

  • The response viewer

With Postman installed, let’s get our hands dirty

Resources

Check these two resources for more clarification on how to use Postman

Video

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