One App to Serve Them All
**Multi-Tenancy** is the defining characteristic of cloud SaaS. It means a single instance of the software serves multiple customers (tenants). Getting this architecture right is critical for margins.
1. Database Isolation Strategies
- Separate Databases: Highest security (good for enterprise/banking clients), but highest cost and maintenance.
- Shared Database, Separate Schemas: A middle ground. Good logical separation but shared resources.
- Shared Database, Shared Schema: Most cost-effective. Data is separated by a ‘TenantID’ column in every table. Requires rigorous code-level security checks.
2. Customization
Each tenant wants the app to feel like their own. Your architecture must support custom branding (white-labeling), custom domain names (CNAME), and configurable feature toggles.
3. The ‘Noisy Neighbor’ Problem
In a shared environment, one heavy user can slow down the app for everyone else. Implementing strict rate-limiting and resource throttling per tenant is mandatory for performance stability.
Conclusion
Multi-tenancy creates economies of scale. It allows you to maintain one codebase and one infrastructure while serving thousands of paying customers.
