Multi-tenancy architecture when building a SaaS
Running many customers on a single, isolated system in a SaaS product: we explain the fundamentals of multi-tenancy architecture.
At the heart of SaaS products lies multi-tenancy: a single application and infrastructure serve many customers (tenants). Done right, it lowers operating cost and makes adding new customers easy.
How do you separate tenant data?
There are three common approaches: a separate database per tenant, a separate schema in a shared database, or row-level separation in a shared database (tenant_id). The row-level approach is the most economical and scalable; but isolating every query to the correct tenant is critical.
Isolation at every layer
- Data: each record belongs to a tenant and queries are automatically isolated.
- Identity: one tenant's session must not be valid in another tenant.
- Configuration: each tenant's settings, theme and features come from data.
- Scale: a heavy tenant must not slow down the others.
In a good multi-tenant architecture, adding a new customer isn't changing code — it's just creating a new record.
Adaptable without changing code
In a strong SaaS, categories, fields and branding are defined by data, not baked into code. So a new customer or a new vertical goes live without rewriting, retesting and redeploying. At Kerte we build SaaS products with exactly this flexibility, on a scalable and secure foundation.