Multi-tenant architectures require careful isolation. After building production multi-tenant systems, here are the strategies that work.

Isolation Strategies

Shared Database, Shared Schema

-- All tenants in same table
CREATE TABLE orders (
    id SERIAL PRIMARY KEY,
    tenant_id INTEGER NOT NULL,
    user_id INTEGER,
    total DECIMAL
);

-- Always filter by tenant_id
SELECT * FROM orders WHERE tenant_id = 123;

Shared Database, Separate Schema

-- Each tenant has own schema
CREATE SCHEMA tenant_123;
CREATE TABLE tenant_123.orders (...);

-- Switch schema per request
SET search_path TO tenant_123;

Separate Database

// Route to tenant-specific database
function getDatabase(tenantId) {
    const shard = getShard(tenantId);
    return databases[shard];
}

Best Practices

  1. Choose strategy - Based on requirements
  2. Enforce isolation - Always filter by tenant
  3. Test thoroughly - Verify isolation
  4. Monitor - Track cross-tenant access
  5. Document - Clear isolation strategy
  6. Security - Row-level security
  7. Backup - Per-tenant backups
  8. Compliance - Data residency

Conclusion

Multi-tenant isolation requires:

  • Clear strategy
  • Consistent enforcement
  • Security measures
  • Compliance considerations

Choose the right isolation level. The strategies shown here secure tenant data effectively.

Multi-tenant isolation strategies from May 2023, covering shared and separate database approaches.