Verification answers “are we building the system right?” — comparing internal artefacts to one another (req vs design, design vs code). Validation answers “are we building the right system?” — comparing the product to stakeholder needs.
Key facts
Verification: internal, developer-led; e.g. reviews, static analysis, type checks.
Validation: external, stakeholder-led; e.g. UAT, demos, beta tests.
Both are needed: you can build the wrong thing perfectly, or the right thing badly.
Verification vs Validation
Verification
ensure the product is built correctly
normally involves two artifacts: req. spec. vs design, design vs code; this is an internal developer activity.