Single-database multi-tenancy is the cheapest kind: one schema, one connection, an organization_id column on every tenant-owned table. The whole design rests on one promise, and it is a promise about forgetting : no developer on the team will ever have to remember to write WHERE organization_id = ? , because forgetting it once leaks another customer's data. Doctrine has had the tool for this for years. It is a SQLFilter , it is about thirty lines, and almost every article about it stops ...