Data Quality platforms validate, test, and enforce data-contract adherence through explicit rules and assertions — the dev-time, deterministic side of data reliability. Core capabilities include assertion frameworks (column null rates, uniqueness, range bounds, referential integrity), data-contract definition and enforcement between producers and consumers, schema tests, CI/CD integration that blocks pull requests on failed data tests, data diffing between environments to catch regressions before deploy, and dbt-native test orchestration. The category sits closer to the engineering workflow than to production alerting. Leading vendors and projects include Great Expectations, Soda (Soda Core / Soda Cloud), Datafold, Elementary, Ataccama, and dbt tests (native to the dbt transformation layer).