Medallion architecture organizes data in layers:
Bronze (Raw): Data exactly as ingested. No transformations. Full history preserved. Used for debugging and reprocessing.
Silver (Cleaned): Deduplicated, validated, standardized. Common schema across sources. Used by data engineers.
Gold (Curated): Business-level aggregations. Dimension and fact tables. Used by analysts and dashboards.
Each layer serves different consumers. Bronze supports reprocessing. Silver enables joins. Gold optimizes query performance.
Databricks popularized this pattern. It works in any lakehouse or warehouse.