Use the Snowflake Horizon Iceberg REST endpoint to read a Snowflake-managed Iceberg table from an external engine

Steps

1. Enable the Iceberg REST catalog feature for your Snowflake account; the catalog endpoint is at https://{account_identifier}.snowflakecomputing.com/polaris/api/catalog
2. Authenticate using key-pair JWT authentication or a Snowflake programmatic access token; generate a JWT signed with your RSA private key and pass it as a bearer token in the Authorization header when initiating the Iceberg REST OAuth flow at /polaris/api/catalog/v1/oauth/tokens
3. Use the catalog endpoint to list namespaces via GET /polaris/api/catalog/v1/{catalog}/namespaces and tables via GET /polaris/api/catalog/v1/{catalog}/namespaces/{namespace}/tables to discover available Iceberg-format objects
4. Configure your external engine (e.g., Apache Spark, Trino) to use the Iceberg REST catalog implementation, pointing the uri to the Snowflake Polaris catalog endpoint and supplying OAuth credentials; the engine will request temporary storage credentials from Snowflake for each scan
5. Snowflake Horizon enforces governance policies (row access, column masking) at the scan plan layer for REST catalog reads; verify that the Snowflake role associated with the credentials has SELECT privilege on the target table