Multi-Tenant Audit Logging: The Architecture Mistakes We Made

We shipped our SaaS product with a single audit_logs table that had a tenant_id column. Seemed fine. Every query filtered by tenant_id. We had an index on it. Done. Then a customer's admin found another customer's audit events in their activity feed. That was the worst Slack message I've ever received on a Friday afternoon. And it was entirely our fault. How the Data Leak Happened The bug was embarrassingly simple. We had a dashboard endpoint that loaded recent audit events for the "current orga