Kensink Labs
Multi-tenant SaaSApplication Design Patterns8-week engagement
PATTERN · MULTI-TENANCY

Multi-tenancy: decide it before you build.

How you isolate tenants is the single hardest thing to change later. We choose the model deliberately, enforce it at the data layer, and make it impossible for one customer to see another's data.

PostgreSQLTypeScriptOAuth
Cycle
8 weeks · fixed price
Stack
Postgres + RBAC
Output
Production code + eval suite
Handoff
Full source ownership
[THE SHORT VERSION]

The decision you cannot cheaply reverse.

Multi-tenancy is a spectrum: shared tables with a tenant id, schema per tenant, or database per tenant. Each trades isolation against operational cost, and migrating between them after launch is brutal. We pick the right point for your security and scale needs, then enforce isolation in code and at the database so a leak is structurally impossible, not just unlikely.

When it fits
  • Any B2B SaaS serving multiple customer organizations
  • Products with per-tenant data, billing, and configuration
  • Apps with compliance or isolation requirements
When it does not
  • Single-tenant or internal tools with one organization
[HOW WE BUILD IT]

How we build with Multi-tenant SaaS.

01

Pick the isolation model

Shared, schema-per-tenant, or database-per-tenant, chosen against your real isolation, scale, and cost needs. This decision drives everything else.

02

Enforce at the data layer

Tenant scoping is enforced in the query layer and, where it fits, with row-level security. Application bugs cannot cross tenants.

03

Tenant-aware everything

Auth, billing, rate limits, and background jobs all carry tenant context. No global job leaks data across customers.

04

Test the boundary

Automated tests that actively try to read across tenants and must fail. Isolation is proven, not assumed.

[WHAT YOU GET]

What the engagement leaves behind.

0
Cross-tenant data paths
Enforced
Isolation at the data layer
Tested
Boundary checked in CI
100%
Source ownership at handoff
[COMMON QUESTIONS]

Questions we get asked.

Shared tables or a database per tenant?
Shared tables with a tenant id scale operationally and suit most SaaS. Database-per-tenant gives the strongest isolation and per-tenant control, at higher operational cost. We choose based on your compliance, scale, and team, and we make the choice explicit rather than accidental.
What about row-level security?
Where it fits, Postgres row-level security adds a database-enforced backstop beneath the application's tenant scoping. Defense in depth: an app bug should not be enough to leak data.
APPLIED K-FRAMEWORK

Bring the problem.
We’ll bring the build.

Eight weeks, fixed price, eval suite at handoff. Senior engineers, full source ownership, no framework lock-in.