Multi-Tenancy
Multi-tenancy is an architecture principle where a single software instance serves multiple customers (tenants) while keeping their data strictly separated.
Multi-tenancy is the architectural foundation of almost all modern SaaS products. From Salesforce and Slack to Shopify: thousands of customers share the same software instance without seeing each other’s data. This model drastically reduces operating cost and allows updates to reach all customers at once. It also demands strong data isolation, security and scalability.
What is Multi-Tenancy?
Multi-tenancy (multi-tenant capability) is a software architecture pattern where one instance of an application serves multiple customers – tenants – at the same time. Each tenant has an isolated data area and can configure the application individually without affecting others. Isolation levels vary: shared database schema with tenant ID as discriminator, separate schema per tenant, or separate database instances. Unlike single-tenancy where each customer has their own instance, in multi-tenancy all customers share infrastructure, which greatly reduces operational effort. The challenge is secure data separation, fair resource sharing (noisy-neighbour problem) and supporting tenant-specific customization.
How does Multi-Tenancy work?
On an incoming request the application identifies the tenant by subdomain, API key or JWT. All database queries are then restricted to that tenant’s data – either by a global filter on tenant ID or by selecting the tenant’s schema or database. Configuration such as branding, permissions and feature flags is stored per tenant. Resource quotas and rate limiting ensure one tenant cannot monopolize the infrastructure. Horizontally, the application scales as the number of tenants grows.
Practical Examples
SaaS CRM: A CRM like Salesforce serves millions of companies on one platform. Each company sees only its own contacts, deals and reports.
E-commerce platform: Shopify hosts hundreds of thousands of shops on the same infrastructure – each with its own design, products and orders.
Project management: Jira Cloud shares infrastructure across all customers; each organization has its own projects, workflows and permissions.
White-label platform: A vendor offers its platform to partners under their branding while all use the same codebase.
Multi-tenant ERP: A cloud ERP serves multiple corporate customers, each with its own tenant and separate accounting and inventory.
Typical Use Cases
SaaS products: Every SaaS that must serve many customers efficiently uses multi-tenancy
White-label solutions: Partners use the same platform under their own branding and data
Internal tenants: Large companies use multi-tenancy to represent subsidiaries or departments in one instance
Platform business: Marketplaces where merchants or service providers run their own areas
Advantages and Disadvantages
Advantages
- Cost efficiency: Infrastructure, maintenance and updates are shared across all tenants
- Simple maintenance: Updates and fixes are deployed once and apply to all customers
- Scalability: New tenants can be onboarded without extra infrastructure
- Faster time-to-market: Once built, the software can be used by many customers immediately
- Consistency: All tenants always run the current version
Disadvantages
- Data isolation: Bugs in tenant separation can let one customer see another’s data
- Noisy neighbour: One resource-heavy tenant can hurt performance for everyone
- Complexity: Tenant-specific configuration, migrations and security increase architecture complexity
- Compliance: Some industries or countries require physical data separation, which complicates multi-tenancy
Frequently Asked Questions about Multi-Tenancy
What is the difference between multi-tenancy and single-tenancy?
How do I ensure tenant data is not mixed?
Which database model is best for multi-tenancy?
Related Terms
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