Quality Assurance

Testing checks whether a product works; quality assurance asks how the team builds products so that they work. QA covers the whole process: writing testable requirements, reviewing designs and code, agreeing on a definition of done, automating tests, checking releases and learning from bugs that reach users. In many companies QA is also the name of a role, the QA engineer, who plans and runs tests and champions quality.

A useful distinction is between assurance and control. Quality control finds defects in a finished piece of work, for example by testing a release candidate. Quality assurance improves the process that produces it, so fewer defects are created in the first place. Both are needed, and modern teams blend them into their everyday work instead of treating them as a final phase.

This blending is often called shifting left: involving testers early, writing automated tests alongside the code, running them on every commit in CI, and adding monitoring and feature flags so problems in production are noticed and contained quickly. Exploratory testing by people still matters, because humans spot confusing behavior that scripted checks miss.

A common misconception is that quality is the QA team's job. When developers hand code over to a separate team to be checked, bugs are found late and fixing them is expensive. Quality is shared: developers own tests for their code, product managers own clear requirements, and QA specialists bring testing expertise and strategy to the whole team.