How do you implement multi-tenancy with a shared database in NestJS TypeORM?

Q: How do you implement multi-tenancy with a shared database in NestJS TypeORM?

// Entity — tenantId on every table @Entity() export class User { @PrimaryGeneratedColumn() id: number; @Column() email: string; @Column({ type: 'uuid' }) tenantId: string; } // REQUEST-scoped repository — auto-injects tenantId from request @Injectable({ scope: Scope.REQUEST }) export class TenantUsersRepository { private tenantId: string; constructor( @InjectRepository(User) private repo: Repository , @Inject(REQUEST) request: Request, ) { this.tenantId = (request as any).tenantId; // set by auth middleware } findAll(): Promise { return this.repo.find({ where: { tenantId: this.tenantId } }); } findById(id: number): Promise { return this.repo.findOne({ where: { id, tenantId: this.tenantId }, // prevents cross-tenant access }); } async create(dto: CreateUserDto): Promise { return this.repo.save({ ...dto, tenantId: this.tenantId }); } } Scope.REQUEST on the repository ensures a new instance per request with the correct tenantId. Scope propagation — every service that injects this repository also becomes REQUEST-scoped. Always include tenantId in WHERE clauses for both reads and writes — never trust client-provided tenantId. Set tenantId from the authenticated JWT in middleware or a guard, not from the request body. Consider PostgreSQL Row Level Security as an alternative for tenant isolation enforced at the database layer.

Difficulty: 6/10

tenant isolation, request‑scoped connection, entity discriminator

Add a tenantId column to every entity as a discriminator. Create a REQUEST-scoped repository that reads tenantId from the incoming request and automatically scopes all queries to the current tenant. This prevents cross-tenant data leaks without requiring every service method to manually pass the tenant identifier.

REQUEST-scoped tenant repository

Multi-tenancy implementation considerations:

1
Scope.REQUEST on the repository ensures a new instance per request with the correct tenantId.
2

How do you implement multi-tenancy with a shared database in NestJS TypeORM?

Difficulty: 6/10

tenant isolation, request‑scoped connection, entity discriminator

Add a tenantId column to every entity as a discriminator. Create a REQUEST-scoped repository that reads tenantId from the incoming request and automatically scopes all queries to the current tenant. This prevents cross-tenant data leaks without requiring every service method to manually pass the tenant identifier.

REQUEST-scoped tenant repository

Multi-tenancy implementation considerations:

1
Scope.REQUEST on the repository ensures a new instance per request with the correct tenantId.
2

How do you implement multi-tenancy with a shared database in NestJS TypeORM?

How do you implement multi-tenancy with a shared database in NestJS TypeORM?

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