By name: multi-tenancy-patterns description: Multi-tenancy implementation patterns for row level security, tenant isolation, and data segregation in SaaS applications.
Multi-Tenancy Implementation Patterns
Use when implementing multi-tenant data isolation, tenant context resolution, or designing tenant-aware entities for SaaS applications.
When to use
- Implementing row level security with shared database architecture
- Creating tenant-aware entities with ITenantEntity interface
- Resolving tenant context from subdomain, custom domain, header, or JWT claim
- Configuring automatic tenant filtering in DbContext with global query filters
- Testing cross-tenant access denial and tenant isolation
Core principles
- Use row level security (shared database) for cost-effectiveness and scalability; all entities implement ITenantEntity
- Resolve tenant in middleware from subdomain → custom domain → header → JWT claim; inject ITenantContext
- Apply global query filters in OnModelCreating for automatic tenant filtering; validate ownership in SaveChanges
- Always include TenantId in WHERE clauses; composite indexes with tenant_id as first column
- Never expose tenant_id in API responses unless needed; log tenant_id for audit trails; monitor cross-tenant access
- Test cross-tenant access denial (unit) and require tenant context for all endpoints (integration)
Resources
- Isolation strategies: patterns/isolation-strategies.md
- Entity structure: patterns/entity-structure.md
- Tenant resolution: patterns/tenant-resolution.md
- Database configuration: patterns/database-configuration.md
- Security considerations: patterns/security-considerations.md
- Performance optimization: patterns/performance-optimization.md
- Testing multi-tenancy: patterns/testing-multi-tenancy.md
Default locations
- Tenant entities: src/GloboTicket.Domain/Entities (inherit from MultiTenantEntity)
- Tenant context: src/GloboTicket.Infrastructure/MultiTenancy/TenantContext.cs
- Resolution middleware: src/GloboTicket.API/Middleware/TenantResolutionMiddleware.cs
- DbContext filters: src/GloboTicket.Infrastructure/Persistence/GloboTicketDbContext.cs (OnModelCreating)
Validation checklist
- All domain entities inherit from MultiTenantEntity and implement ITenantEntity
- TenantResolutionMiddleware resolves tenant from subdomain/domain/header/JWT and injects ITenantContext
- DbContext applies global query filters to all ITenantEntity types in OnModelCreating
- SaveChanges sets TenantId for new entities and validates ownership for updates/deletes
- All queries explicitly include TenantId filter (even with global filters for clarity)
- Composite indexes include tenant_id as first column for tenant-scoped queries
- API responses do not expose tenant_id unless explicitly needed; logged for audit
- Unit tests verify cross-tenant access denial; integration tests require tenant context for endpoints