ping-openmls-sdk

OpenMLS-based secure messaging for browsers, React Native, RN-Web, and Electron/Tauri. Crypto runs in a Web Worker so the UI is never blocked.

Install

npm install ping-openmls-sdk

Usage

import { MessagingClient } from "ping-openmls-sdk";
import { IndexedDbStorage } from "ping-openmls-sdk/storage/indexeddb";
import { WebSocketTransport } from "ping-openmls-sdk/transport/websocket";

// 1. Identity — generate once per user, then persist (encrypted) by your auth flow.
const identityExport = await MessagingClient.generateIdentity();

// 2. Plug in storage + transport.
const storage   = new IndexedDbStorage();
const transport = new WebSocketTransport({ baseUrl: "https://relay.example.com" });

// 3. Init.
const client = await MessagingClient.init({
  identityExport, deviceLabel: "Web", storage, transport,
});

// 4. Use.
const convo = await client.createConversation({ name: "Team" });
await convo.addMembers([bobKeyPackage]);
await convo.send(new TextEncoder().encode("hello"));

client.onMessage((msg) => {
  console.log(new TextDecoder().decode(msg.plaintext));
});

// 5. Catch up after reconnect.
await client.syncConversations();

Architecture

The SDK is a thin TypeScript shell over a Rust core compiled to WebAssembly. The Worker owns the WASM instance; the main thread does not import WASM at all. See docs/ARCHITECTURE.md for details.

Bundle size

Aim: ≤ 350 KiB gzipped for the WASM blob, ≤ 8 KiB gzipped for the TS surface. We achieve this by:

• Building the WASM with --release, wasm-opt -O3, and stripping symbols.
• Lazy-initializing WASM only on first init() (so MessagingClient.generateIdentity() doesn't pay the cost on cold pages).
• No CBOR or crypto libraries on the main thread.

React Native

On RN, native binaries are preferred — install ping-openmls-sdk-react-native-macos (autolinked). On RN-Web, this package's WASM build is used as-is.