Brief

Hina is a multi-tenant SaaS platform that lets language learning studios manage courses, students, and assignments from a shared infrastructure while keeping tenant data strictly isolated.

Studio owners configure their subdomain, branding, and curriculum; students access their portal through the branded URL. The platform handles billing, seat limits, and content delivery.

Process

The initial architecture used row-level tenant isolation in a single PostgreSQL database. As the tenant count grew past 30, query plans started ignoring indexes due to bloated statistics.

We migrated to a schema-per-tenant model. Each new tenant gets a dedicated PostgreSQL schema provisioned automatically at signup via a Cloudflare Worker that runs Flyway migrations. This kept query plans predictable and simplified data residency requirements for European customers.

The frontend is a Nuxt 3 app deployed to Cloudflare Pages, with a shared component library published as a private npm package consumed by each tenant's customizable shell.

Tech Decisions

The key design challenge was enabling tenant customization without forking the codebase.

The edge worker resolves the tenant from the hostname, injects a config header (X-Tenant-ID, X-Tenant-Theme), and forwards to the Nuxt app. The app reads the header to select the correct PostgreSQL schema and apply the tenant's design tokens at runtime.

This avoided a per-tenant deployment model while keeping strict data isolation — a deliberate trade-off between operational simplicity and isolation granularity.