🔐 Pocketbridge

End-to-end encrypted, cross-device sync for files, messages, and clipboard. The server is a zero-knowledge relay — it never sees your plaintext.

Pocketbridge is split into three repositories that move together:

Repo	Role	Stack
🖥️ pocketbridge-backend	Zero-knowledge relay + device pairing	Node, Express, WebSocket, Redis, PostgreSQL
🌐 pocketbridge-frontend	Web client (offline-capable PWA)	Next.js, TypeScript
📱 pocketbridge-mobile	Mobile app	Expo / React Native, TypeScript

How it works

   📱 mobile  ──┐                                   ┌──  🌐 web
   (RN/Expo)    │  pair via QR, then exchange only  │     (Next.js PWA)
                │  ENCRYPTED blobs                   │
                ▼                                    ▼
          ┌───────────────────────────────────────────────┐
          │   pocketbridge-backend (zero-knowledge relay)  │
          │   Node + Express + WebSocket + Redis pub/sub    │
          │   ► pairs devices, routes ciphertext            │
          │   ► NEVER holds keys, NEVER sees plaintext      │
          └───────────────────────────────────────────────┘

Security model

• MTProto 2.0-style protocol, implemented on NaCl / tweetnacl primitives.
• Ed25519 signatures (device identity), ECDH key agreement, HKDF key derivation.
• All encryption happens on-device; the relay only ever forwards ciphertext.
• Yjs CRDTs keep multi-device state conflict-free.

Why it's three repos

Each client (web, mobile) and the relay deploy independently and have different runtimes, so they live in separate repos — grouped by the pocketbridge topic.

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Built by Bishwas Khanal.