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LoadFire is an easy to script load balancer and reverse proxy in NodeJS.

It allows you to write your own pieces of logic as "Patterns" and the core engine takes care of all the proxying logic so you don't have to worry about it.

The real power is that all it's behavior is entirely scriptable in JavaScript (NodeJS). :)

This allows for many different use cases, such as:

  • Dynamic realtime proxying rules (domain mappings stored in Redis for example). Such things are useful for PaaSs
  • Add pieces of middleware to your reverse proxy
  • Customizable load balancing patterns (Sticky, RoundRobin, ...)

It supports proxying:

  • WebSockets


Proxying HTTP traffic using RoundRobin pattern

var http = require('http');
var loadfire = require('loadfire');
var EDITOR_PORTS = [7001, 7002, 7003,7004];
var EDITOR_SERVERS = (x) {
    return {
        host: 'localhost',
        port: x
// Start all our different http servers 
function startEditorServers(ports) {
    ports.forEach(function (port) {
        // Setup HTTP Server 
        var httpServer = http.createServer(function(req, res) {
            // Output the port number the server is running on 
            res.writeHead(200, {'Content-Type': 'text/plain'});
        // Listen on assigned port 
// Config for our loadfire server 
var CONFIG = {
    'resources': [
            // resource is some value identify this resource 
            // by default it should be the hostname to match 
            resource: 'localhost:8000',
            // List of backends to hit 
            backends: EDITOR_SERVERS,
            // Load balancing pattern 
            // As of now a few are builtin 
            // random, roundrobin, sticky 
            pattern: 'roundrobin'
    // Server to start loadfire on 
    port: 8000
function main() {
    // Start our http servers 
    // Setup our load balancer with the above config 
    var loadServer = loadfire.createServer(CONFIG);
    // Now start our load balancer;
    // Check out localhost:8000 
    // Refresh a few times and you'll see different port numbers appear 
    // depending on which http server the requests are proxied to 
    // since we are using the roundrobin pattern it will cycle through them 
// Run main 

It was initially built to satisfy our needs at FriendCode, and we've been using it in product for months without any issues, so it can be considered as stable.

The API however will be changed soon due to some design decisions aiming to simplify it's API. (Patterns are quite monolithic as of now, they will be split up into different parts: matcher, mapper, balancer, store).