Verification vs validation in testing
Updated 2026-11-13 · 2 min read
Distinguish conformance to requirements from fitness for user needs, with a booking example and an interview answer. Includes a comparison table, concrete examples and an interview answer.
The difference in one table
| Aspect | Verification | Validation |
|---|---|---|
| Main question | Does the work meet its specified requirements? | Does the product meet its intended use? |
| Reference | Requirements, design and other specifications | User goals and operating context |
| Example evidence | Review results, analysis and test results | Representative workflows and acceptance evidence |
| Typical risk found | Implementation differs from the agreed rule | Agreed rule fails to solve the user problem |
| Timing | Throughout development | Throughout development |
Examples
Verification: an OTP requirement says a code expires after the configured validity period. Review the rule for ambiguity, then test the expiry boundary and confirm the implementation follows it.
Validation: a booking user may lose their seat reservation while waiting for an OTP. Walk through the booking with representative users and realistic delivery delays to assess whether the whole journey serves the intended purpose. Matching the OTP rule alone does not answer that question.
How to answer in an interview
Verification checks conformance to specified requirements, while validation checks suitability for the intended use. I might verify the OTP expiry rule and validate whether the booking journey lets users complete a reservation. Both should influence development early. “Building the product right” and “building the right product” are helpful reminders, but I explain the actual evidence I would collect.
Common confusion
The shortcut “verification is static, validation is dynamic” is too restrictive as a universal definition. Reviews are useful verification activities, but execution can also verify requirements. Likewise, user feedback on a prototype can expose a validation problem before the final product exists.
Likely follow-up: Can a product pass verification and fail validation? Yes: a booking flow may implement every agreed rule yet be unusable for its intended users.
This is independent foundation-level learning material, not affiliated with ISTQB.
Quick answers
Is validation only user acceptance testing?
No. Acceptance testing can provide validation evidence, but prototypes, user feedback and other evaluations can also inform intended-use decisions.
Who owns these activities?
Responsibility is shared across the team and stakeholders. The test team contributes evidence; it does not replace product or user decisions.
Sources
Want a project you can show in interviews?
The portfolio project kit walks you through testing a deliberately buggy app with Selenium or Playwright and API tests, then explaining it. The app itself is free.