Warehouses and databases (BigQuery, Snowflake, Redshift, PostgreSQL, MySQL, MongoDB, Elasticsearch, SQL Server, Oracle, Firestore, and more), product analytics (GA4), and ad platforms (Google Ads, Meta Ads, YouTube). You connect through a read-only service account you control, so Heimdall sees only what you grant. Queries run in your warehouse; only the results come back, never your raw tables. Heimdall also plugs into Slack — ask questions and get briefings where your team already works.