Multi-Tenancy With Postgres Row-Level Security in Ktor

Thu, 09 Jul 2026 00:00:00 +0000

Introduction

Moxie IT (the company I co-own) developmed a time tracking and invoicing tool called MinuteMint as an alternative to Harvest. It runs in production and supports multi-tenancy from the first migration: every client, project, time entry and invoice belongs to exactly one tenant.

That raises a question you have to answer on day one, because it is expensive to answer later:

Where does tenant isolation actually live?
What happens when a developer forgets to apply it?
How do you prove, in a test, that a tenant cannot see another tenant’s rows?

The default answer in most codebases is “in the query”. I think that is the wrong place.

Multi-Tenancy on Jamie Craane personal blog

Multi-Tenancy With Postgres Row-Level Security in Ktor

Introduction