chat-app

Private, end-to-end encrypted chat app for a small circle. Self-hosted Supabase backend, clients on iOS, Android, macOS, Windows, and Linux.

Server is zero-knowledge: it only stores ciphertexts and metadata needed to route them.

Milestone Roadmap

1. Milestone 1 — Text Chat (current): auth, identity keys, 1:1 encrypted messaging, local history, push.
2. Milestone 2 — Voice Calls: libsodium-secured WebRTC signaling via Supabase Realtime.
3. Milestone 3 — Video Calls: same stack, add video tracks + bandwidth handling.
4. Milestone 4 — Desktop Polish: feature parity with mobile, tray, notifications.
5. Milestone 5 — Groups & Channels: Discord-like group channels with shared ratchet keys.

Repository Layout

apps/
  mobile/      Expo + React Native (iOS / Android)
  desktop/     Tauri v2 + React + Vite + Tailwind (macOS / Windows / Linux)
packages/
  shared/      Business logic: Supabase client, libsodium crypto, auth, chat
  db-types/    Generated Supabase database types
  ui-web/      React web components shared by desktop (not by React Native)
infra/
  supabase/    Self-hosting docs, client env, SQL migrations
.github/workflows/  CI + build placeholders

Tech Stack

• Mobile: Expo SDK 52, Expo Router, expo-secure-store, expo-sqlite, expo-notifications, react-native-libsodium.
• Desktop: Tauri v2, React 18, Vite, Tailwind, tauri-plugin-stronghold, tauri-plugin-sql, tauri-plugin-notification, Zustand.
• Backend: Supabase self-hosted (Postgres + GoTrue + PostgREST + Realtime + Storage + Edge Functions) on Hetzner, Caddy reverse proxy.
• Crypto: X25519 identity keys, XChaCha20-Poly1305 envelopes (libsodium / NaCl).
• Auth: email magic-link, invite-only.

Prerequisites

• Node 22+ (see .nvmrc)
• pnpm 9+
• Rust + Cargo (Tauri): https://rustup.rs
• Docker + Docker Compose (for running Supabase locally or on the VPS)
• Platform toolchain per target:
  • iOS: Xcode
  • Android: Android Studio + SDK
  • macOS/Linux/Windows Tauri: see apps/desktop/README.md

Setup

# 1. Node + pnpm (macOS)
brew install pnpm
corepack enable

# 2. Clone + install
git clone <this repo>
cd chat-app
pnpm install

# 3. Env
cp infra/supabase/.env.example apps/mobile/.env
cp infra/supabase/.env.example apps/desktop/.env
# Fill in SUPABASE_URL and SUPABASE_ANON_KEY from your self-hosted stack.

See infra/supabase/README.md for spinning up the backend.

Common Scripts (run from repo root)

Script	Purpose
pnpm dev	Start every workspace's dev task (Turborepo).
pnpm build	Build every workspace.
pnpm lint	ESLint across workspaces.
pnpm typecheck	TypeScript project-wide type check.
pnpm test	Vitest across workspaces.
pnpm format	Prettier write.
pnpm format:check	Prettier check.
pnpm mobile:dev	expo start for the mobile app.
pnpm mobile:ios	Native iOS run.
pnpm mobile:android	Native Android run.
pnpm desktop:dev	tauri dev for the desktop app.
pnpm desktop:build	Platform-specific Tauri bundle.
pnpm db:types	Regenerate @chat-app/db-types from the running Supabase.

Architecture Overview

• Shared-first: Anything that can run in both React Native and the Tauri WebView lives in packages/shared and is imported via @chat-app/shared/*. Both hosts pass in adapters for platform-only concerns (secure storage, SQLite, libsodium backend).
• Zero-knowledge server: Messages are encrypted client-side before insert. The server sees ciphertexts, a conversation id, a sender id, and a timestamp — nothing else.
• Key custody: X25519 private keys live in platform secure stores only (Keychain/Keystore on mobile, Stronghold on desktop). Public keys live in the profiles table.
• Realtime: Supabase Realtime delivers new ciphertext rows to subscribed clients. Push notifications are silent (data-only) — the client decrypts and composes the visible notification locally.

Security Checklist

• RLS enabled on every user-facing table
• Invite-only enforced in SQL (invites table + policy)
• No plaintext in push payloads
• Service role key never shipped to a client
• JWT secret rotated on first boot
• TLS via Caddy at the edge