Chapter 2 – Testing Throughout the SDLC
Non-Functional Testing – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
Testing performed to evaluate that a component or system complies with non-functional requirements such as performance, usability, reliability, security and portability.
In simple words
How fast, how secure, how usable, how reliable — the ‘qualities’ around the feature, not the feature itself.
Exam tip
Learn the ISO 25010 characteristics — CTFL v4.0 uses them to categorize non-functional testing.
Related terms
- Functional TestingDoes the feature do what the spec says? Login logs you in, checkout charges the right amount.
- Performance TestingHow fast, how many users, how stable under load — response time, throughput, resource usage.
- Security TestingTrying to break in, leak data, or escalate privileges — before an attacker does.
Practice this term in the ISTQB Mock Test
40 CTFL v4.0 questions, 60-minute timer, instant scoring and chapter-wise breakdown.
Practice in Mock Test