So you want to learn about API testing?

TL:DR – see below section for a list of useful resources to begin learning more about Application Programming Interface (API) testing.

Today I got a message from Coders Guild software testing graduate Alexander Olakunle, who I have to say I found to be a very dedicated and driven person, who has worked incredibly hard on the course and landed his first testing job with Ordinance Survey (congrats again Alexander!). He asks:-

During the short training course, we cover API testing, but only from a high, theoretical level.

I thought it might be helpful to others (that means you!) to list some excellent, beginner-friendly resources to try out if you’re in a similar position to Alexander.


If you like seeing how different people tackle the same problem, I’d definitely recommend taking a look at the Test.Bash(online) talks from the Ministry of Testing. 4 different sets of people answered the same challenge, and gave demo’s on how they did it – so many useful tidbits of practical insight there.

Postman Galaxy is a huge conference that still has most of its 2021 talks available online – another great resource to familiarise yourself with. Don’t worry about watching all of the talks, just skim them and know they’re there if you need more detail in future – learn the why, Google the how!


Myself, Andy Knight and Ben Dowen did a podcast about API testing topics with Qualitest you might find useful.


Dave Westerveld has created a great book (published by Pakt) called “API Testing and Development with Postman” which serves as a fantastic introductory book for API testing (don’t let the development bit of the title put you off!).

Short Courses/Tutorials

Ministry of Testing’s 30 Days Of API Challenge

Test Automation University, Amber Race’s course: Exploring Service API’s through Test Automation

If you complete that course, you can then go on to do my Test Automation Course API Test Automation with Postman, particularly if you’ll be using the Postman tool for your testing efforts. If REST Assured is something you’ll be using, Bas Djikstra has a TAU course on that too.


I’ve only very recently become aware of this, but there is an organisation called API United, who have created an API testing certificate. It currently costs £170 to take the exam in the UK, but the syllabus is available online so its possible that this would be all it costs you to get the API-U Certified API, Rest & Microservices Tester (CARMT) with Postman or Karate

Screenshot showing the certification title and API United logo

Of course certification isn’t for everyone, but if you feel it would benefit you it might be worth taking a look.

More Advanced Stuff

Lewis Prescott – A master of all things contract testing, anything he appears in is a great resource if this is an area of API testing you want to learn more about, especially his podcast series “How to start API Contract Testing

Mark Winteringham – Not a lot of people know this 😉 but Mark is gearing up to publish the final version of his incredible book Testing Web APIs. Its got loads of practical exercises in, so if you enjoy working through those you will get so much out of reading this book.

Of course, its well worth doing your own research, and I’d love to hear if you have found other resources elsewhere that you’ve benefitted from – drop me a comment and let me know, that way I could learn something new too!

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