Emojitsu

Emojitsu is an async multiplayer emoji auto-battler RPG. Players pick an emoji, name it, equip up to three permanent cards at the start, and challenge other emojis in server-simulated round battles. Opponents do not need to be online: when they return, they see how many battles happened, which ones were won or lost, and which rewards were earned.

Tech stack

• Next.js App Router
• React + TypeScript
• Supabase Auth + Postgres
• Supabase Row Level Security for player-owned data
• Vitest for isolated game-rule tests

Game architecture

The core rule code is intentionally independent from React and Supabase:

src/lib/game/
  battle-engine.ts     deterministic round simulation
  calculate-power.ts   central combat-power formula
  cards.ts             starter card catalog
  leveling.ts          XP and level progression
  matchmaking.ts       power-range opponent selection
  rewards.ts           weighted card rewards

The client never decides battle outcomes. A server path should:

1. load both character loadouts and decks,
2. simulate the battle with a server-generated seed,
3. persist the battle log, XP changes, and card reward,
4. return the battle id so the UI can replay the stored log.

Supabase schema

Initial schema lives in:

supabase/migrations/20260609175505_initial_schema.sql

Tables:

• profiles
• characters
• cards
• player_cards
• deck_slots
• battles

All public tables have RLS enabled. Client-visible keys must be provided via:

NEXT_PUBLIC_SUPABASE_URL=https://xqbnqfntxeaqbcjakzfd.supabase.co
NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY=sb_publishable_WSExgYEUSmMbfKqCkCoOuA_UQsUHRRK

Copy .env.example to .env.local for local development.

Project:

• Supabase project: Emojitsu
• Project ref: xqbnqfntxeaqbcjakzfd
• Region: eu-west-1

Auth flow

Emojitsu starts with a kid-friendly anonymous Supabase account:

1. A new player clicks Sofort spielen.
2. The browser creates an anonymous Supabase Auth user.
3. The player chooses an emoji and name on /onboarding.
4. profiles and characters rows are stored with the authenticated user_id.
5. Returning on the same device reuses the cookie-backed session.

Enable Anonymous Sign-ins in the Supabase project's Auth providers before using the flow in production.

Progress can be secured in two ways:

1. Login code — color + animal + two digits (e.g. blauerelefant65), created in the dashboard
2. Email — links the anonymous account via Supabase updateUser

Log in on a new device via /login. Set the Supabase Auth redirect URL to https://<your-domain>/auth/confirm for email confirmation.

Local development

npm install
npm run dev

Quality checks:

npm run typecheck
npm run test
npm run build

MVP routes

• / landing page with a simulated battle summary
• /dashboard offline battle inbox concept
• /opponents targeted and automatic matchmaking concept
• /deck starter card/deck concept
• /battle/demo replay prototype for a stored battle log