• Easy-to-use syntax unified across protocols
• Flexible and extensible, create your own transports and buffering strategies
• Can be used between servers or in the browser
• Lower resource footprint and better throughput than plain sockets
• Zero dependencies and can be bundled down to ~5kb!

Performance

The performance gain comes from buffering packets before sending them- eventually sending batches instead of individual packages. The more traffic getting processed, the better the improvement. Many strategies are offered as routines. You can read more about the packet buffering algorithm here

Install

Install the core package

npm install kalm

Install the transport layer ('tcp' for example)

npm install @kalm/tcp

Usage

Server

const kalm = require('kalm');
const ws = require('@kalm/ws');

const server = kalm.listen({
  port: 8800,
  transport: ws(),
  routine: kalm.routines.tick({ hz: 5 }), // Sends packets at a frequency of 5 Hz (200ms)
  host: '0.0.0.0',
});

server.on('connection', (client) => {
  client.subscribe('channel1', (body, context) => {
    // When receiving messages from this client on "channel1"
    console.log(body) //
    console.log(context) //
  });

  // Sends a message to all clients on "channel2"
  server.broadcast('channel2', 'some message');
});

Client

const kalm = require('kalm');
const ws = require('@kalm/ws');

const client = kalm.connect({
  host: '0.0.0.0',
  port: 8800,
  transport: ws(),
  routine: kalm.routines.realtime(),
  // socket: new WebSocket(...), // You can also pass a socket object, which unlocks compatibility with many other libraries, like https://github.com/joewalnes/reconnecting-websocket
});

client.on('connect', () => {
  client.subscribe('channel1', (body, context) => {
    // When receiving messages from the server on "channel1"
    console.log(body); // 
    console.log(context); //
  });

  // Sends a message to the server on "channel2"
  client.write('channel2', 'hello world');
});

To see working implementations, check out our examples folder.

• Peer to peer with WebRTC
• Distributed Pub-Sub
• Binary packet compression
• Basic Typescript usage

Documentation

[Read more]

• Transports [wiki]
  • @kalm/ipc
  • @kalm/tcp
  • @kalm/udp
  • @kalm/ws
• Routines [wiki]
  • realtime
  • dynamic
  • tick

Logging

Kalm uses the NODE_DEBUG environment variable. Just include kalm in your value.

Example:

NODE_DEBUG=net,kalm node myApp.js

Events

Kalm servers offers events to track when packets are processed by routines or when a raw frame is received.

| Server Event | Payload | Description | | --- | --- | --- | | error | Error | (server, client) Emits on errors. | | ready | void | (server) Indicates that the server is now actively listening for new connections | | connection | Client | (server) Indicates that a client has successfully connected |

Kalm clients offers events to track when packets are processed by routines or when a raw frame is received.

| Client Event | Payload | Description | | --- | --- | --- | | error | Error | (server, client) Emits on errors. | | connect | void | (client) Indicates that a client has successfully connected | | disconnect | void | (client) Indicates that a client has disconnected | | frame | { body: Partial<RawFrame>, payloadBytes: number } | (client) Triggered when receiving payloads, can be used to intercept messages from non-kalm counterparts. |

Testing

npm test

npm run bench

Contributors

Code Contributors

This project exists thanks to all the people who contribute. [Contribute].

If you think of something that you want, open an issue or file a pull request, we'll be more than happy to take a look!

License

Apache 2.0 2025 Frederic Charette