Designing a Single-Database Multi-Tenant SaaS in Laravel

Why single-database multi-tenancy

When you build a SaaS that serves many companies, the first big decision is how to isolate their data. A separate database per tenant is simple to reason about but expensive to operate at scale. A single database with company-level isolation keeps operations simple while still giving each tenant a clean, private view of their data.

The core building blocks

• Company scoping — every tenant-owned table carries a company_id, enforced by a global scope so you never forget the where clause.
• Branch scoping — within a company, data is further scoped to a branch, which matters for POS and inventory.
• RBAC — roles and permissions are evaluated per company, not globally.
• Audit logs & module controls — every meaningful action is recorded, and features can be toggled per plan.

A note on performance

Multi-tenancy lives and dies by your indexes. Composite indexes that lead with company_id keep tenant queries fast, and caching the hot, rarely-changing lookups (settings, permissions) avoids hammering the database on every request.

Build the isolation in from day one. Retrofitting tenant scoping onto a single-tenant app is one of the most painful migrations you can take on.