Understanding Multi-Tenancy Patterns
When building enterprise platforms for franchises, isolating data per store is an absolute requirement. Multi-tenancy can be approached via three primary database models: database-per-tenant (highest isolation, highest cost), schema-per-tenant (balanced), or shared-database with tenant-ID column-level isolation (lowest cost, highest risk).
Implementing Row-Level Security (RLS)
In PostgreSQL, Row-Level Security (RLS) provides a robust framework to enforce tenant isolation at the database tier, preventing accidental leakages between store contexts even if the application layer has a bug.
ALTER TABLE store_transactions ENABLE ROW LEVEL SECURITY;
CREATE POLICY tenant_isolation_policy ON store_transactions
FOR ALL TO authenticated_users
USING (tenant_id = current_setting('app.current_tenant_id'));API Routing for Franchises
We structure our Next.js API routes to always extract the tenant ID from the subdomain or the verified JWT. This prevents IDOR (Insecure Direct Object Reference) vulnerabilities, as the backend context is inherently tied to the active franchise.
- Store tenant configurations in a fast access cache like Redis.
- Ensure all backend database queries append the tenant_id automatically.
- Use custom domains with SSL certificates provisioned dynamically via Let's Encrypt.