Advanced – Non-Functional Testing
Reliability – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
The degree to which a system performs specified functions under specified conditions for a specified period (ISO/IEC 25010).
In simple words
How consistently the system stays up and correct over time.
Exam tip
Includes maturity, availability, fault tolerance and recoverability.
Related terms
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