What is the role of a QA engineer?

A QA (Quality Assurance) engineer is responsible for ensuring software quality throughout the development lifecycle — not just finding bugs, but preventing them. Responsibilities: (1) Requirements review: identify ambiguities and testability issues before development. (2) Test planning and strategy: define what, how, and when to test. (3) Test case design: create comprehensive test cases covering happy paths, edge cases, and error scenarios. (4) Test automation: write and maintain automated test suites (E2E, API, performance). (5) Defect reporting: clear, reproducible bug reports. (6) Regression testing: ensure new changes don't break existing functionality. (7) Performance and security testing coordination. (8) CI/CD pipeline: ensure tests run automatically. Modern QA evolution: the "shift-left testing" movement integrates QA earlier — QA engineers work alongside developers, review code, and help developers write better unit tests. Some organizations move to "quality engineering" where all engineers are responsible for quality, with QA providing expertise and tooling. The role is evolving from "manual tester" to "quality enabler."