What is Reverse ETL?

Reverse ETL (Extract, Transform, Load) is the process of transferring data from a data warehouse or data mart back to the source systems. This is typically done to update or correct data in the source systems, or to synchronize data between multiple systems.

Reverse ETL is often used in scenarios where data has been extracted from the source systems, transformed and loaded into a data warehouse or data mart for analysis and reporting, and then changes are made to the data in the data warehouse. In order to ensure that the source systems have the most up-to-date data, the changes made in the data warehouse must be propagated back to the source systems. This is where reverse ETL comes in.

Reverse ETL typically involves the following steps:

1. Extracting the updated or corrected data from the data warehouse or data mart.
2. Transforming the data to match the format and structure of the source systems.
3. Loading the transformed data back into the source systems.
4. Validating and reconciling the data to ensure that it has been successfully transferred and that it is accurate and up-to-date.

Reverse ETL can be an effective way to ensure that data remains consistent and up-to-date across multiple systems, and can help to avoid the problems that can arise from having inconsistent or outdated data.