ETL and ELT

ETL (Extract, Transform, Load) and ELT (Extract, Load, Transform) are the two primary patterns for moving data from operational sources into analytical stores. ETL transforms data before loading and was dominant in the on-premise era when storage was expensive. ELT loads raw data first, then transforms inside the cloud data warehouse where compute is elastic and cheap. Modern data stacks favor ELT with tools like Fivetran/Airbyte for extraction-and-load, then dbt for in-warehouse transformation. Empire325 builds modern ELT pipelines with rigorous testing, documentation, and CI/CD, ensuring transformations are version-controlled and auditable.