My Experience Passing the ISTQB CTFL (Certified Tester Foundation Level) Exam
Introduction
Hi, I’m Jeongil Jeong, a backend developer with 3 years of experience.
I recently passed the ISTQB Certified Tester Foundation Level (CTFL) certification, and I’d like to share my experience.
ISTQB stands for International Software Testing Qualifications Board, and it’s one of the most internationally recognized certifications in the software testing field. CTFL is the Foundation Level — the entry-level certification in the ISTQB framework.
Why Did I Take the CTFL?
Honestly, the motivation wasn’t anything grand.
As a backend developer, writing test code is a natural part of the job. But looking back, I think I spent a long time thinking about testing as just “checking whether the code works correctly and whether the business logic runs as expected.” I never really thought systematically about what testing methodologies exist or how to design tests properly.
Because of that, I often relied on intuition when writing test code — thinking “this should be enough, right?” That always left me feeling a bit uneasy, and I started wanting to properly study testing as a discipline.
On top of that, I’ve been thinking about eventually transitioning into a DevOps role. Since DevOps work includes building test automation pipelines, I figured having a solid understanding of testing theory would come in handy. ISTQB also has more specialized certifications beyond CTFL, so I’ve been considering pursuing something like the Certified Tester Automotive Software Tester (CT-AuT) down the road.
With all that in mind, I came across ISTQB CTFL while looking into testing certifications. Since it’s the entry level, it seemed like a good way to build a structured foundation in testing concepts. I also had enough development experience that I figured a short preparation period would be sufficient, so I didn’t hesitate long.
Exam Overview and Preparation
Since CTFL is an international certification, the process varies by country. In Korea, it’s administered by the Korean Software Testing Qualifications Board (KSTQB), with periodic offline exams at designated venues. I took the exam at SpaceShare Samsung Station Center (B1F, Daehwa Building, 20 Yeongdong-daero 96-gil, Gangnam-gu, Seoul). The exam is paper-based — you mark answers on an OMR sheet using a water-based marker pen. There are 40 questions total, with 60 minutes for Korean-language test takers and 75 minutes for English-language test takers. The passing score is 65%, meaning you need to answer at least 26 out of 40 questions correctly.
I prepared for about 4–5 days. Having a development background, the testing concepts weren’t entirely foreign to me, which I think is why I was able to get ready in a relatively short time.
There are already plenty of well-organized study guides out there covering the exam scope and preparation strategies, so I’ll just share the materials I personally used:
- Silvernuss PDF Material
- If you’re preparing for CTFL, chances are you’ve already come across this. It covers the exam syllabus in an organized way and was a huge help for getting a solid grasp on the concepts.
- KSTQB Official Sample Papers A–D
- These can be downloaded as PDFs from the KSTQB official website. I went through each set at least 3 times. These were the most important resource for understanding the types of questions on the exam.
Exam Results and Honest Review
I’m happy to say I passed with a score of 75.
The first thing I thought during the exam was that “the real exam is noticeably harder than the sample papers.” Other people’s reviews say it feels about 1.5x harder than the samples, and I’d say that’s about right.
That said, the content itself isn’t hard. The concepts aren’t particularly difficult. What makes the exam tricky is the way questions are written — they tend to be intentionally confusing. The answer choices are often crafted so that two or more options seem correct, which means if you don’t have a precise understanding of the concepts, you’ll find yourself going back and forth between very similar-looking options.
Repeating the sample papers does help you recognize patterns, but the real exam twists those patterns just enough that you really need to understand the concepts properly to get to the right answer.
Would I Recommend CTFL?
Honestly, I’d say it’s probably not worth it unless you’re pursuing a QA role.
There are two main reasons.
The first is the cost. The exam fee in Korea is 198,000 KRW, which is close to 200,000 KRW. I’m genuinely not sure how much weight CTFL carries in the job market for developers in non-QA roles. My gut feeling is that it’s probably not that significant.
The second is relevance to your role. If you work in QA, this certification makes clear sense. But for other developers, the positioning feels a bit ambiguous.
If you’re someone like me who wants to study testing more systematically, the preparation process does help you build a clearer perspective on what good testing looks like. That said, if that’s your main goal, you might get just as much out of reading the Silvernuss material or the official ISTQB syllabus without spending close to 200,000 KRW.
Closing
That wraps up my ISTQB CTFL experience.
More than the score itself, what I found valuable was the shift in perspective — starting to see testing as a professional discipline in its own right rather than just something developers do on the side.
That said, I can’t easily recommend it to developers who aren’t in or targeting a QA role. The honest conclusion is that the cost-to-benefit ratio feels a bit underwhelming for general developers. If I ever transition into DevOps and find myself building test automation pipelines as part of CI/CD work, something like CT-AuT might start to look more compelling — but that’s a decision for future me.
Thank you for reading this long post!
