Architecture

The application is a Nuxt 4 single-page app with Nuxt UI. Pages and components under app/ call Nitro endpoints under server/api/ through $fetch. Zod schemas in shared/schemas/ validate input, while the side-effect-free cost engine lives in shared/domain/print-calculation.ts.

Browser → route middleware → Nitro API → service → Prisma → SQLite /data/app.db
                                  ↘ Zod   ↘ Decimal calculation

First-run setup creates User, AppSettings, and any selected synthetic demo data atomically. Demo calculations use the configured currency and electricity price, while optional series and spool records follow their feature flags. Passwords use Argon2. Random session tokens exist only in an HTTP-only, SameSite=Lax cookie; the database stores SHA-256 hashes. Writes reject foreign origins. Business routes require a session; setup status, setup, sign-in, and health do not.

Prisma uses the synchronous Better-SQLite3 adapter, so writes and setup target one process and one container replica. Startup applies migrations and Nitro shutdown disconnects Prisma. See Deployment.

The current scope excludes multi-user roles, cloud synchronization, multiple currencies per instance, slicer imports, quotes and invoices, email password reset, and horizontal scaling. Extensions should add versioned domain contracts instead of mutating historical snapshots.