What is Reverse ETL?

Reverse ETL is the practice of syncing transformed data out of a cloud data warehouse and into the operational SaaS tools where business teams actually work, the CRM, the marketing automation platform, the ad networks, the support desk. It is the mirror image of ELT: where ELT and ETL move data into the warehouse for analysis, reverse ETL moves the results of that analysis back out so they can drive action. The motivating problem is that the warehouse holds the richest, most complete view of a customer (purchase history, product usage, computed lifetime value, churn risk) but salespeople and marketers live in tools that cannot see it. Reverse ETL closes that gap by treating the warehouse as the source of truth and continuously materializing audiences, traits, and scores into downstream systems. This is the foundation of operational analytics and the modern customer data platform pattern. The hard parts are mapping warehouse models to each tool's API schema, handling rate limits, and keeping syncs idempotent so a retry does not double-write. For an AI agent automating go-to-market workflows, knowing which fields are reverse-ETL'd and authoritative versus manually entered prevents it from overwriting computed data, useful context to keep in shared memory.