Building a multi-tenant SaaS application using Node.js needs a strategic architecture. In a multi-tenant model, a single codebase should be able to serve different tenants. But each tenant may require separate data storage, configuration and even features.
Multi-Tenant SaaS Platforms in Node.js
1. Choose a Multi-Tenancy Model
There are three common approaches:
| Model | Description | Advantages | Disadvantages |
| Shared Database, Shared Schema | All customers share the same database and tables. Each row includes a tenant_id to identify the customer. | Simple to set up, low cost | Weaker data isolation, must enforce row-level security carefully |
| Shared Database, Separate Schema | One database instance, but each customer has a separate schema with its own set of tables. | Better data separation, moderate complexity | Harder to manage schema updates, more complex migrations |
| Separate Database per Tenant | Each customer has a completely separate database or database cluster. | Strongest isolation, easier to back up or export per customer | Highest cost, more infrastructure and management required |
2. Directory & Code Structure
/src /tenants tenantManager.js // Handles tenant config and DB connection mapping /modules /users /projects /middlewares /services app.jsMake use of a TenantManager that loads DB connections dynamically or when you set it to per request. Make sure to store tenant-specific metadata (plan, DB, URI, config) in a central database or config service.
3. Routing and Middleware
Use Express middleware to inject tenant context into every request:
app.use(async (req, res, next) => { const subdomain = extractSubdomain(req.hostname); req.tenant = await tenantManager.getTenantConfig(subdomain); next();
});This allows services and DB operations to be tenant-aware.
4. ORM/ODM Configuration
If using Sequelize or Mongoose, create tenant-specific instances:
const connection = mongoose.createConnection(tenant.mongoUri);Final Thoughts:
Hire Node.js developers that can design your system for isolation, easy onboarding, and per-tenant scaling. With a dynamic tenant manager, middleware-based context injection, and flexible DB strategy, Node.js becomes a powerful backend for multi-tenant SaaS platforms.
