Express Setup

LoadFlux integrates as standard Express middleware.

Basic setup

import express from "express";
import { loadflux } from "loadflux";

const app = express();

app.use(loadflux({
  auth: {
    username: "admin",
    password: "secret",
  },
}));

// Your routes
app.get("/api/users", (req, res) => {
  res.json([{ id: 1, name: "Alice" }]);
});

app.listen(3000, () => {
  console.log("Server running on http://localhost:3000");
  console.log("Dashboard at http://localhost:3000/loadflux");
});

Using environment variables

import { loadflux } from "loadflux";

app.use(loadflux({
  auth: {
    username: process.env.LOADFLUX_USERNAME || "admin",
    password: process.env.LOADFLUX_PASSWORD || "password",
  },
}));

Create a .env file:

LOADFLUX_USERNAME=admin
LOADFLUX_PASSWORD=your-secure-password

Custom dashboard path

app.use(loadflux({
  path: "/monitor",
  auth: { username: "admin", password: "secret" },
}));
// Dashboard at http://localhost:3000/monitor

Excluding routes from monitoring

Health checks and internal routes can be excluded:

app.use(loadflux({
  auth: { username: "admin", password: "secret" },
  excludeRoutes: ["/health", "/ready", "/metrics"],
}));

Full example

import express from "express";
import { loadflux } from "loadflux";

const app = express();

app.use(loadflux({
  path: "/loadflux",
  auth: {
    username: process.env.LOADFLUX_USERNAME || "admin",
    password: process.env.LOADFLUX_PASSWORD || "password",
  },
  database: {
    adapter: "sqlite",
    connectionString: "./data/loadflux.db",
  },
  retention: { days: 30 },
  slowRequestThreshold: 1000,
  excludeRoutes: ["/health"],
}));

app.get("/health", (req, res) => res.send("ok"));
app.get("/api/users", (req, res) => res.json([]));
app.get("/api/users/:id", (req, res) => res.json({ id: req.params.id }));

app.listen(3000);

How it works

LoadFlux middleware does two things:

1. Serves the dashboard — Requests to /loadflux and /loadflux/* are handled by LoadFlux (dashboard UI, API, SSE).
2. Records metrics — All other requests pass through to your routes. On response finish, LoadFlux records the method, route pattern, status code, duration, and response size with < 0.5ms overhead.

Route patterns are automatically normalized using req.route.path, so /api/users/1 and /api/users/2 are grouped under /api/users/:id.