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SaaS Architecture·8 min read
Multi-Tenant SaaS: Choosing the Right Isolation Model
By DEV3 Engineering
The isolation model is the hardest decision in a SaaS product to reverse. It affects your security posture, your migration strategy, your hosting bill and how quickly you can onboard a new customer.
The three common models
- Shared tables with a tenant ID: cheapest and simplest to operate, but you need strict query scoping.
- Schema per tenant: stronger isolation and per-tenant migrations, with moderate operational overhead.
- Database per tenant: maximum isolation for regulated industries, and the highest operational cost.
Most products we build start with shared tables plus a mandatory tenant filter enforced in the data layer. Enterprise customers who need it get a dedicated-database tier later.