A Data Driven Testing (DDT) developer creates automated tests that use different sets of data, enabling the retesting of the same functionality with varying inputs. Through DDT, they can run the same test scenario multiple times but with different data values, enhancing test coverage and efficiency. They focus on separating test scripts from test data, storing the data externally. This allows them to test how the system behaves with different data sets. They manage data sources, implement code for data extraction, and analyze results. Their work minimizes manual intervention and maximizes code reusability and efficiency.