Guide to Using Postgres Row-Level Security for Multi-Tenant SaaS Data Isolation

A technical guide outlines strategies for isolating customer data in SaaS applications. It compares three common architectural approaches: shared schema, schema per tenant, and database per tenant. The article advocates for a shared schema model protected by PostgreSQL's Row-Level Security feature as a cost-effective and robust solution. This method moves data access rules from application code into the database to prevent accidental data leaks. It includes practical implementation steps, such as creating security policies and managing database connections within transactions.