@pochta-chat/sdk

The framework-agnostic client SDK for Pochta — a self-hosted, end-to-end-encrypted messenger where the relay is a post office, not an archive.

This package is everything a client needs to speak the Pochta protocol: self-owned identity, sign-then-seal E2E crypto, the relay transport + all message operations (text, edit/delete/react/reply, receipts, typing), voice/video call signaling, and encrypted media. It ships no storage engine and no UI — you inject those — so the same core runs a web app, a desktop/mobile app, or a headless bot.

Published on npm as @pochta-chat/sdk (ESM + type declarations, built with tsup). Also a workspace package (packages/sdk) that the in-repo web app consumes via a @pochta-chat/sdk alias to its TypeScript source. npm i @pochta-chat/sdk.

What you inject

| Port | What it is | Browser example | |----------------|---------------------------------------------------------|-----------------| | Store | durable message/contact/media history (the source of truth lives on the device) | IndexedDB | | KVStore | small key-value for the encrypted account vault + device id | localStorage | | relay URLs | socketUrl (ws) + httpBase (http) | derived from the page origin | | ClientEvents | UI callbacks (onMessage, onPresence, onCallState, …) | React state setters |

The SDK never imports a database, a UI framework, or a hardcoded server address.

Quick start

import {
  createIdentity, Vault, Client,
  type Identity, type Store, type ClientEvents,
} from "@pochta-chat/sdk";

// 1. Identity (self-owned keypair; 12-word backup). Persist it under a passphrase.
const id: Identity = createIdentity();
const vault = new Vault(localStorage);      // any KVStore
await vault.persist(id, "correct horse battery staple");

// 2. Supply a Store (durable history). Implement over IndexedDB / SQLite / memory.
const store: Store = myStore;

// 3. Connect. Events drive your UI.
const events: ClientEvents = { onMessage: render, /* …the rest… */ } as ClientEvents;
const client = new Client({
  socketUrl: "wss://relay.example.com/socket",
  httpBase:  "https://relay.example.com",
  identity: id,
  store,
  events,
  deviceId: vault.deviceId(),
});
client.connect(await loadContacts());
await client.sendText(recipientPubkeyHex, "Hello over Pochta 👋");

Surface

• Identity — createIdentity, restoreIdentity, sign, authParams, Vault.
• Crypto — seal, open, deriveEncryptionKey (+ SealedEnvelope, OpenedMessage).
• Client — Client (text, media, edit/delete/react, receipts, typing, presence, voice/video calls) + ClientConfig, ClientEvents.
• Media — encryptAndUpload, downloadAndDecrypt.
• Discovery / onboarding — inviteToken, parseInvite, enroll.
• Protocol — PROTOCOL_VERSION, inboxTopic, EVENTS, SOCKET_PATH.
• Model & ports — Store, KVStore, StoredMessage, StoredContact, MediaRef, Body, PresenceInfo, CallState.

Dependencies

Audited primitives only: @noble/curves (Ed25519 + X25519), @noble/ciphers (XChaCha20-Poly1305), @noble/hashes, @scure/bip39. Transport uses phoenix (peer dependency). Calls use the platform's WebRTC (RTCPeerConnection) when present — absent in Node, so a headless bot simply doesn't place calls; messaging works everywhere.