Bidirectional Iceberg Writes with Horizon Catalog

This article details Snowflake's bidirectional Iceberg interoperability, announced at Snowflake Summit 2026, which allows external engines like Spark and Trino to write to Snowflake-managed Iceberg tables through the Horizon Catalog. It covers the technical architecture using Apache Polaris for metadata management and governance, the REST Scan Plan API integration, credential vending, and ACID consistency. The article also compares Horizon Catalog with Databricks Unity Catalog and provides guidance on getting started with bidirectional writes, making it a valuable resource for tech professionals working with data lakes and cloud data platforms.