Multitenant

Multitenancy is a software architecture pattern in which a single instance of a software application serves multiple distinct tenants. Each tenant uses the same code base and resources but has logical isolation of data, configurations, and metadata. Tenants are managed independently, and access control enforces that a user from one tenant cannot access another tenant's data.

Databases and data models in multitenant systems vary. Common models include separate databases per tenant, a shared database with separate schemas per tenant, or a single database with a tenant identifier used to partition data within shared tables. The choice affects isolation, scalability, maintenance, and cost. The application layer typically enforces tenancy through context or middleware, while the data layer enforces access controls and data separation.

Benefits of multitenancy include lower infrastructure and operational costs, easier software updates, and faster onboarding of new tenants. Challenges include ensuring robust data isolation to prevent leakage, managing performance isolation to avoid noisy-neighbor effects, and addressing regulatory or compliance requirements that govern data governance, auditing, and retention.

Security and governance considerations are central. Multitenant systems require strong tenant-aware access controls, comprehensive auditing, encryption of data at rest and in transit, and reliable backups. Compliance with data protection regulations may dictate data location, retention, and disclosure practices. Tenants may have different service levels, making capacity planning and performance management essential, often supported by resource quotas, throttling, and isolation at the application or infrastructure level.

Lifecycle and deployment practices are critical in multitenant SaaS platforms. Tenant provisioning, configuration management, data isolation, and secure offboarding must be automated and auditable. Modern deployments frequently use virtualization or containerization to manage resource allocation and isolation at scale.