Multi-tenancy in Laravel: How to Build a Scalable SaaS Platform.

Wat is multi-tenancy?

Suppose you’re building a software platform for HR teams. Your first client is a manufacturing company with 200 employees. The second is a law firm. The third is a logistics service provider. Three different organizations, each with their own users, their own data, and their own processes. You have two options: run a separate installation for each client, or build a single application that serves all three while keeping their data strictly separate. The second option is multi-tenancy.

One application, multiple clients: how does that work?

In a multi-tenant system, each client is a "tenant." For every incoming request, the application identifies which tenant is behind it—typically via a subdomain (productioncompany.yourplatform.nl), a URL segment, or a JWT token—and serves only that tenant's data.

The challenge lies in the separation. A bug in your tenant identification that allows tenant A to view tenant B’s data is not just a technical issue. It is a privacy incident.

Multi-tenancy vs. multiple installations: the difference.

Multi-tenant systems are easier to build and fully isolated. However, they do not scale well. Each new client requires a new server, a new database, new deployments, and duplicate maintenance. With ten clients, this is already cumbersome. With a hundred, it becomes unsustainable. Multi-tenancy solves this by sharing infrastructure without mixing data.

The two main strategies in Laravel.

One database per tenant: maximum isolation.

Each tenant is assigned its own database. For each request, the application dynamically connects to the appropriate database based on the tenant's identification.

• Advantages: maximum data isolation, easy compliance (each tenant's data is physically separated), easy to back up per tenant and export upon termination.

• Disadvantages: higher infrastructure costs with many tenants, more complex migrations (each database must be updated), and a higher management burden.

Shared database with tenant_id: cost-effective and flexible.

All tenants share a single database. Each table contains a tenant_id column. The application automatically filters all queries to the active tenant.

• Advantages: lower infrastructure costs, simpler migrations (one-time execution), better suited for platforms with many small tenants.

• Disadvantages: higher risk of data leaks if the tenant filter is not applied consistently, more complex compliance with strict data location requirements, and potential performance issues as the database grows.

A hybrid approach: when it makes sense.

Some platforms combine the two strategies: a shared database for non-sensitive data (configuration, logging) and separate databases for sensitive data (personal information, financial records). This requires more architectural work but offers the best of both worlds.

Multi-tenancy implementeren in Laravel: packages.

Tenancy for Laravel: flexible and feature-rich.

"Tenancy for Laravel" by Arkadiusz Kondas is the most mature open-source solution. It supports both database-per-tenant and shared-database approaches, offers automatic tenant identification via subdomains or domains, and comes with comprehensive documentation.

The package uses the concept of "bootstrappers" to reconfigure the application for the active tenant on a per-request basis. Cache, queue, storage, database: everything is automatically switched.

Laravel Jetstream and Spark: Teams and Billing.

Laravel Jetstream offers a built-in "teams" structure that functions as a lightweight multi-tenancy solution. This works well for platforms where users can belong to multiple teams and data is separated at the team level.

Laravel Spark adds billing capabilities: subscription management via Stripe, directly integrated with your tenant structure. For SaaS platforms where tenants sign up for subscriptions, this is a major game-changer.

Build it yourself vs. use a package

For simple use cases involving a shared database and a limited number of tenants, building your own implementation using global scopes is feasible. The pitfall: you end up slowly recreating what the packages already do well, but without the battle-tested edge cases. For more complex requirements, a package is almost always the better choice.

Pitfalls of multi-tenancy and how to avoid them.

Prevent data leaks between tenants.

This is the biggest risk. A query that accidentally fails to apply a tenant filter will return data from all tenants. In Laravel, you can prevent this by using a global scope that is automatically applied to every model, and by testing this with integration tests that explicitly verify that tenant A does not see data from tenant B.

Performance bij shared database.

As the database grows, queries may become slow. Ensure that every table containing tenant data has an index on tenant_id. Consider database sharding if the volume grows significantly. Monitor query times per tenant to detect performance issues early on.

Manage migrations by tenant.

With a per-tenant database setup, every migration must be run on all tenant databases. Tenancy for Laravel includes built-in support for this. With a custom solution, this is a common mistake: migrations are run on the primary database but are forgotten for existing tenants.