If you’ve started looking into software testing as a career, you’ve probably come across the term “API testing” fairly quickly. It sounds technical, and it can be at first, but it’s actually one of the most approachable ways to move from manual testing into automation. It’s also one of the most in-demand skills on a QA tester’s CV in Ireland right now.
This guide breaks down what API testing actually is, why it matters, and how a tool called Postman makes it beginner-friendly.
API stands for Application Programming Interface. In plain terms, it’s the messenger that lets two pieces of software talk to each other.
Think about a weather app on your phone. You don’t see the actual weather stations or databases. The app sends a request (“give me today’s forecast for Dublin”) to a weather service, and the API is what carries that request back and forth and returns the data.
Almost every modern app or website relies on APIs behind the scenes: logging in, processing a payment, loading your bank balance, submitting a form. All of it usually involves an API call happening quietly in the background.
API testing means checking that these behind the scenes requests work correctly, without needing to click through the actual app or website at all.
Instead of testing through the user interface (clicking buttons, filling in forms), you’re testing the layer underneath it. You send a request directly to the API and check things like: did it return the right data, did it come back in the right format, was it fast enough, and does it handle errors properly when something goes wrong?
This matters because a lot of bugs live at the API level, not the surface level. An app might look fine on screen but be sending or receiving broken data underneath. API testing catches those issues earlier and faster than clicking through the UI ever could.
A few years ago, “QA tester” mostly meant manual testing through a browser or app. That’s changed. Today, most QA job listings in Ireland, junior and senior alike, mention API testing as a core skill, right alongside tools like Selenium or Cypress.
There are practical reasons employers want this:
This is where a tool called Postman comes in. It’s the industry-standard tool for API testing, and it’s also one of the friendliest tools a beginner can pick up.
In simple terms, Postman lets you send a request to an API and see exactly what comes back, without needing to build or click through an actual app. From there, you can start defining what a “correct” response should look like, so the tool tells you automatically if something’s wrong rather than you having to check it manually every time.
It’s a genuinely popular starting point for people moving from manual testing into something more technical, precisely because it eases you in gently, with real hands-on testing concepts rather than a steep learning curve.
API testing with Postman rarely stands alone in a real QA role. It usually sits alongside manual testing skills and browser automation tools like Selenium, Cypress, and Playwright. Employers want testers who understand the full picture: manual testing fundamentals, browser automation, and API testing underneath it all.
Business Technology Academy’s QA Testing Course is designed for career changers and upskilling professionals alike. You’ll get hands-on, practical training in Selenium, Playwright, and Cypress — the exact tools employers are hiring for — within a structured, supportive environment that prepares you for the AI-integrated reality of modern quality engineering. You can check our the Course Syllabus in the Courses Page
Business Technology Academy is a member of Aontas, the Irish National Adult Learning Organisation, Cyber Ireland, Ireland’s Cyber Security Industry Association and is accredited by the European Association for Higher Education
