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QA Guide to REST API Testing for Beginners (Udemy.com)

Get skilled at using Postman and Fiddler to create, call, and test REST APIs for software testing

Created by: Glitch IT System

Last updated April 2026

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What you will learn

  • You will learn what APIs are and how they work
  • You will be skilled at using Postman and Fiddler to create, issue requests, and test APIs
  • You will learn how to use Fiddler to capture, view, replay, and manipulate web traffic
  • You will be able to read and create JSON data
  • You will learn some javaScript

How it compares

Against the other 1,182 rated Udemy courses in IT & Software on CourseDuck:

  • Rating4.5 out of 5higher than 45% of them
  • Reviews350#666 of 1,183 by number of reviews
  • Length5.5 hoursshorter than 49% of them
  • Last updatedApril 2026more recently than 72% of them

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Course Description

Welcome!

This is the third course in my "QA Guide" series. Application QA Engineers are high on the list of great jobs that can earn you over $100k a year. Take the next step to achieve your maximum earning potential.


What are APIs? And how do we test them?

APIs are an extremely important part of the applications that we use everyday. There are APIs being called every time you open an app on your phone, search for products on the web, or play a song from your Alexa.

If your team is developing a mobile app or web application, there are going to be APIs involved. You need to be able to understand what APIs are, how they work, and how to test them.


Are you ready to work with APIs?

In this course you will learn everything that you need to know to get started with REST API testing.

The course starts with API basics. Here you will learn what an API is and how they work.

I will be covering several tools along the way to help you validate and format APIs so that you can quickly and easily understand the purpose and content.

You will learn some javaScript which is essential when working with REST APIs.

The bulk of the course will be through exercises. We will use Postman to generate API requests. Then we will use Postman to test the requests that we created.

Finally, we will be using Fiddler to capture, view, and manipulate API Traffic.


Get started now!

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Instructor Details

Glitch IT System

I’m a Senior QA Engineer with 20+ years of experience leading QA teams and delivering high-quality software. I specialize in testing web and mobile applications, building test automation frameworks, and mentoring new testers. My background also includes front-end development, which helps me bridge the gap between testers and developers.

Now, I’m focused on sharing practical, real-world QA skills to help you grow your career and build applications your users will love.

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Reviews

4.5

350 ratings on Udemy

Select a bar to show only those reviews.Select the bar again to show every rating.

By Marta Mirror on 11/18/2025

Unfortunately some of elements don't work anymore - numbersapi, omdb keys apparently has to be paid for, so there is no update to the course and you have to search on your own. It lacks a bit of explanation ad hoc, e.g. when something is explained, it would be nice to see how it works in real cases, to visualize it better for the student. The course includes very basic introduction though, which is good and sufficient if someone knows completely nothing about APIs and how to create requests from scratch.

By Lora Evans on 7/15/2021

For someone with no exposure to API before, the course was difficult to follow along. especially at the beginning. I did not understand how to navigate Sublime, how to open the page, how to get out of the previously open page. I navigate blindly on all the steps the instructor demonstrated, but I would have to take this course more than once to be able to work it on my own. This is more an intermediate course than a beginners' course. I would say, the best way to understand it is to install the applications as instructed and follow along.

By Faizan Bashir on 7/4/2021

This was my first ever Udemy course, and the first time learning about using tools and mindset for dealing and testing APIs. The different free APIs used during the course was a really fun and engaging way to build muscle memory and lay bases for later lectures. All the videos are to the point and precise. I have watched most of it on 1.5 play back speeds, not sure if this was intentional :)

By Ahmed Ali on 3/14/2021

Course is dry good, well explained and to the point. The instructor speaks very clearly and goes at a steady pace. Just one thing to ask, in the preview of the course I see that jmeter is listed in the contents, however there was no mention of jmeter in the course?

By Dimitar Stojanovski on 1/10/2021

I highly recommend this course for those who want to learn the basics of API Testing and how to use Postman. The instructor was pretty good, he explained the modules in simple language and was easily understandable. Looking forward for intermediate course on this topic.

By Ciaran Starrs on 9/14/2020

It's a great introduction to the subject. Some may find it a little slow, but it works well as a beginner's course since the instructor is very clear and doesn't presume any prior knowledge. I found it easy to follow and learned a lot. Thank you!

By Neil Dutta on 8/25/2020

Great pace, everything was clear and I was able to understand everything and it was the right amount of information. This guide was the type of intro guide I was looking for. The instructor actually teaches how to use Postman the correct way, I had inexperienced colleagues in the past show me the wrong way (or inefficient slow method) and this course makes it a lot clearer on how to run API tests which can be reused with variables so that you can scale your API testing efforts.

By Cynthia Harrell on 5/24/2020

This is a great class and I have learned so much. The instructor is easy to understand. He presents his material in a clear manner and touches on topics that I can use right away. I look forward to taking other classes with this instructor. Thank you, I hope you have an advanced course I can take next.

By Miriam Kocourková on 4/13/2020

In this course I learned what was promised. With almost no prior knowledge I feel it will be easier for me to use Postman and read json data with much better understanding. The instructor explains nicely as he goes. When he makes a mistake, which happens to all of us at work, he shows how he approaches the solution, which I see as a benefit.

By Jeffrey Helwig on 12/19/2018

A great introduction to APIs and API testing. The instructor was clear and to the point. He has a clear speaking voice and the quality of the presentation was excellent. I am a Mac user, so a resource like Fiddler that is in Beta is a little worrying for my OS, an alternate (if available) would be appreciated.

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Overall Score : 90 / 100