Introduction

This project is a TypeScript drawing application with guest storage on the device, authenticated scenes, real-time rooms, a hand-drawn renderer, and Redis write-behind persistence.

These notes describe what each folder owns and how the folders talk to each other. They never explain code — for behaviour, read the linked sources in the repo itself. Where the repo was unclear, the page says so.

Start with Installation, then the Monorepo layout, then the High-level architecture.

Tech stack at a glance

The codebase is TypeScript throughout, running on Node 24 or newer with pnpm workspaces. The drawing engine is custom code on the canvas API — no drawing library appears in any workspace manifest.

Language and tooling

Frontend

Realtime and backend

Data

Quality

Workspace	Role	Language and runtime	Key libraries
Web	Next.js editor, account dashboard, and room access interface.	TypeScript, CSS · Node >=24	Next.js React React DOM Tailwind CSS
HTTP server	Authenticated HTTP API for scenes, rooms, invites, files, and private library items.	TypeScript · Node >=24	tsx Express CORS Zod
WebSocket server	Authenticated room WebSocket transport for presence, scene changes, selections, and laser trails.	TypeScript · Node >=24	TypeScript tsx ws
Flush worker	BullMQ worker that flushes Redis room state to durable Prisma snapshots.	TypeScript · Node >=24	TypeScript tsx
Common	Platform-neutral element models, collaboration protocols, validation, and reconciliation.	TypeScript · Node >=24	Vitest
Engine	Browser-independent drawing geometry, tools, renderer, scene capture, and history.	TypeScript · Node >=24	Vitest
Backend common	Server-only collaboration and access operations shared by HTTP, WebSocket, and worker apps.	TypeScript · Node >=24	Vitest
Database	The sole Prisma schema, database client, repositories, migration graph, and schema snapshots.	TypeScript, Prisma schema · Node >=24	TypeScript tsx node-postgres Prisma ORM Prisma CLI
Auth	Better Auth configuration, browser auth client, email delivery, and authentication helpers.	TypeScript · Node >=24	TypeScript Better Auth bcrypt jsonwebtoken dotenv
Redis	Redis live room state, pub/sub, rate limiting, and write-behind queue integration.	TypeScript · Node >=24	TypeScript tsx BullMQ ioredis
Validations	Reusable request validation schemas.	TypeScript · Node >=24	Zod
UI	Shared UI primitives.	TypeScript · Node >=24	TypeScript React
Tooling configs	Collection of internal eslint configurations.	· Node >=24	ESLint ESLint JS config React Hooks plugin Globals
Tooling configs	Shared TypeScript configurations.	· Node >=24	—