Baseline testing is a testing practice that establishes a stable reference version of an application against which future changes can be evaluated. This baseline represents an accepted level of functionality, performance, and reliability that the system must continue to meet as it evolves.

By comparing new test results with the baseline, teams can quickly identify regressions, performance drops, or unexpected behavior introduced by recent changes. This makes baseline testing especially valuable in environments with frequent releases or continuous integration, where changes are introduced regularly.

Baseline testing is often used alongside regression and performance testing to provide meaningful context for test results. When the baseline is updated thoughtfully after major improvements or releases, it helps teams track quality trends over time.

Overall, baseline testing supports data driven decisions, reduces risk during releases, and ensures that progress does not come at the cost of stability or user experience.