librelay - Forsta Relay Node.js library

Signal based Node.js library for end-to-end crypto with Forsta messaging platform.

NPM License Change Log Docs


This is a Node.js library used to communicate with the Forsta messaging platform. The underlying protocol is based on the Signal end-to-end crypto system. The primary differences surround how provisioning is done and the data payload, which is a custom JSON specification,


Ensure that you are using Node 8 (needs async/await support) or higher and simply install from NPM:

$ npm install librelay


Librelay needs a backing store for holding crypto material. The default storage backing is fs which will store files in your local file-system under ~/.librelay/storage. Redis is also supported by setting RELAY_STORAGE_BACKING=redis in your env or calling'redis').

To support multiple instances of librelay on a single backing store you can specify a custom label. This essentially operates as a namespace for all storage data. The storage label can be set via the env, a la. RELAY_STORAGE_LABEL="special" or by calling'special') from inside your application.

You'll need to ensure your backing store is running properly with a call to await, and if possible you should tear it down before quitting, with await


PREREQUISITE: To use librelay you must first have a valid Forsta account. You can sign-up for free at Once you have a valid Forsta account you need to provision your librelay based application.

With your Forsta account (e.g. myusername:myorgname) you can get started with the registerAccount function or the registerDevice function if adding supplemental devices.

const relay = require('librelay');

async function main(secondary) {
    const userTag = await relay.util.consoleInput("Enter your login (e.g user:org): ");
    const challange = await relay.AtlasClient.requestAuthentication(userTag);
    const prompt = challange.type === 'sms' ? 'SMS Code: ' : 'Password: ';
    await challange.authenticate(await relay.util.consoleInput(prompt));
    if (secondary) {
        const registration = await relay.registerDevice();"Awaiting auto-registration response...");
        await registration.done;"Successfully registered new device");
    } else {
        await relay.registerAccount();"Successfully registered account");



Message Receiving

Once your application is provisioned you can participate in the messaging platform. The simplest way to get familiar with the platform is to listen for incoming messages and examine the content sent to your application in a debugger. Here is a very simple example of receiving messages.

const relay = require('librelay');

function onMessage(ev) {
    const message =;"Got message", message);

async function main() {
    const msgReceiver = await relay.MessageReceiver.factory();
    msgReceiver.addEventListener('message', onMessage);
    await msgReceiver.connect();



Message Sending

This example reads text from standard input and forwards to a hard coded thread.

const process = require('process');
const relay = require('librelay');

async function main() {
    const argv = process.argv;
    if (argv.length < 4) {
        console.error(`Usage: ${argv[0]} ${argv[1]} TO MESSAGE [THREADID]`);
        return process.exit(2);

    const sender = await relay.MessageSender.factory();
    await sender.send({
        to: argv[2],
        text: argv[3],
        threadId: argv[4] || '00000000-1111-2222-3333-444444444444'



Cryptography Notice

This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See for more information.

The U.S. Government Department of Commerce, Bureau of Industry and Security (BIS), has classified this software as Export Commodity Control Number (ECCN) 5D002.C.1, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this distribution makes it eligible for export under the License Exception ENC Technology Software Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Section 740.13) for both object code and source code.


Licensed under the GPLv3:

  • Copyright 2014-2016 Open Whisper Systems
  • Copyright 2017-2019 Forsta Inc.