Multi-tenant Architecture Examples - Inspiration & Best Practices

Multi-tenant architecture is the foundation of scalable SaaS platforms. By serving multiple customers (tenants) on the same infrastructure, SaaS companies can share costs, roll out updates faster, and scale more efficiently. The challenge lies in balancing data isolation, performance, and per-tenant customisation. Multiple architecture patterns exist, each with their own advantages and trade-offs. In these examples, we show how organisations have implemented multi-tenant architecture in practice.

Shared database with row-level security for an HR SaaS

An HR SaaS platform serves 500+ companies from a single shared PostgreSQL database. Row-level security (RLS) policies guarantee that each tenant can only read and write their own data. The application layer automatically injects tenant context with every query. This approach minimises operational complexity and makes central database management, indexing, and query optimisation straightforward across the entire customer base.

• PostgreSQL row-level security for watertight data isolation
• Automatic tenant context injection at the application level
• Shared indexes and query optimisation across all tenants
• Simple migrations executed in one operation for all tenants

Database-per-tenant for a financial SaaS platform

A financial SaaS platform handling sensitive financial data chose database-per-tenant isolation. Each customer receives their own database instance, ensuring data is physically separated. A central management layer handles provisioning, migrations, and monitoring of all tenant databases. While operationally more complex, this choice was necessary to meet the strict compliance requirements of financial regulators.

• Physical data isolation with dedicated database instance per tenant
• Central management layer for provisioning and migration management
• Per-tenant backup and restore capabilities
• Compliance with financial regulations through strict isolation

Hybrid multi-tenant architecture for an e-learning platform

An e-learning platform implemented a hybrid approach: small customers share a database with RLS, while enterprise customers receive a dedicated database. The application automatically routes requests to the correct database based on tenant configuration. This approach combines cost efficiency for the majority of customers with maximum isolation and performance for enterprise accounts that pay a premium.

• Automatic tenant routing to shared or dedicated database
• Seamless upgrade path from shared to dedicated database
• Configurable resource limits per tenant tier
• Central monitoring dashboard across all tenant databases

Multi-tenant with custom domains for a website builder

A website builder SaaS implemented multi-tenancy where each customer can use their own domain or subdomain. A reverse proxy routes traffic to the correct tenant based on the incoming domain. Each tenant can configure their own theme, branding, and content while the underlying codebase is fully shared. Automatic SSL certificate generation via Let's Encrypt ensures secure connections per custom domain.

• Domain-based tenant routing via reverse proxy
• Automatic SSL certificate generation per custom domain
• Configurable theme and branding per tenant
• Shared codebase with tenant-specific configuration overrides

Key takeaways

• Shared database with RLS is the most cost-effective approach for most SaaS platforms with standard isolation requirements.
• Database-per-tenant provides maximum isolation but significantly increases operational complexity and costs.
• A hybrid approach combines the best of both worlds by differentiating tenant tiers.
• Tenant context must be watertight: a bug in tenant filtering can cause catastrophic data leaks.

How MG Software can help

MG Software designs and builds multi-tenant architectures that fit your SaaS business model. We advise on the right isolation level, implement watertight tenant filtering, and ensure scalable infrastructure. Our experience with PostgreSQL RLS, tenant routing, and database-per-tenant patterns guarantees a solid technical foundation for your SaaS platform.