backend-logger

A simple, powerful request logger for Express. See every request your server handles — with colors, timing, and zero setup.

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What Does This Do?

Every time someone visits your server, this package prints a line showing what they asked for, how your server responded, and how long it took. That's it.

[2026-04-16T10:30:00.000Z] GET     /users/42   200   4.05ms

Reading left to right: the time, the request method, the URL, the response status, and how long it took.

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Install

npm install backend-logger

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Use It (30 seconds)

Just add one line to your Express app:

const express = require('express');
const { requestLogger } = require('backend-logger');

const app = express();

app.use(requestLogger());  // ← that's it

app.get('/', (req, res) => res.send('Hello!'));
app.listen(3000);

Now every request gets logged automatically. You don't need to change your routes or controllers.

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What You Get by Default

When you just call requestLogger(), each log line shows:

What you see	Example
Time	[2026-04-16T10:30:00.000Z]
Method	GET, POST, PUT, DELETE
URL	/users/42
Status	200 (green if OK, red if error)
Duration	4.05ms

Status codes are color-coded:

• 🟢 2xx — success
• 🔵 3xx — redirect
• 🟡 4xx — client made a mistake (like "not found")
• 🔴 5xx — your server crashed

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Want More? Add Fields

You can log many more things by listing the fields you want:

app.use(requestLogger({
  fields: ['method', 'url', 'status', 'duration', 'timestamp', 'ip', 'handler']
}));

Available Fields

Field	What it shows
method	GET, POST, etc. (default)
url	/users/42 (default)
status	200, 404, 500 (default)
duration	How long the request took (default)
timestamp	When it happened (default)
route	The route pattern, e.g. /users/:id
handler	The name of the controller function that handled it
baseUrl	Router mount point, e.g. /api/v1
requestId	A unique ID for tracing one request across your logs
ip	Who made the request (their IP address)
userAgent	What browser or tool they used
headers	All HTTP headers they sent
body	The request body (POST/PUT data)
query	The ?key=value stuff in the URL
params	Values like :id from routes
contentLength	How big the response is
referer	The page that linked to yours
protocol	http or https
hostname	yoursite.com

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"Which Controller Ran?" — The Most Useful Field

Ever wondered "which function handled this request?" This is the magic:

function getUserById(req, res) {
  res.send('user data');
}

app.get('/users/:id', getUserById);

app.use(requestLogger({
  fields: ['method', 'url', 'route', 'handler', 'status', 'duration']
}));

Output:

GET  /users/42  200  4ms  route=/users/:id  → getUserById

Now you know exactly which function handled which URL. No more guessing.

Tip: Always give your controller functions names (don't use arrow functions like (req, res) => {}), otherwise handler shows <anonymous>.

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Save Logs to a File

Don't just print to the screen — save them for later:

app.use(requestLogger({
  transports: ['console', 'file'],    // where to send logs
  filePath: 'logs/requests.log',      // where to save them
}));

Now logs go to both your terminal AND a file. Easy.

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Use JSON Format (for Production)

If you're running in production and using a log tool (like Datadog, Papertrail, etc.), use JSON:

app.use(requestLogger({
  format: 'json',
  transports: ['file'],
  filePath: 'logs/app.log',
}));

Each line becomes a parseable JSON object:

{"timestamp":"2026-04-16T10:30:00.000Z","method":"GET","url":"/users/42","status":200,"duration":4.05}

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Skip Certain Requests

Don't want to log health checks or static file requests? Use skip:

app.use(requestLogger({
  skip: (req) => req.url === '/health' || req.url.startsWith('/static/')
}));

Any request where skip returns true won't be logged.

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Trace a Request Across Your App (Request IDs)

Each request gets a unique ID automatically. You can use it in your own logs too:

app.use(requestLogger({
  fields: ['requestId', 'method', 'url', 'status', 'duration']
}));

app.get('/users/:id', (req, res) => {
  console.log(`[${req.id}] Fetching user ${req.params.id}`);
  // All your logs for THIS request share the same ID
  res.send('ok');
});

Why this helps: When something goes wrong, you can search your logs for that one ID and see everything that happened during that request.

The ID is also sent back in the response header X-Request-ID, so the client can reference it too (e.g., in a bug report).

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Common Setups (Copy-Paste Ready)

Development — Nice and Detailed

app.use(requestLogger({
  fields: ['method', 'url', 'status', 'duration', 'timestamp', 'route', 'handler', 'query']
}));

Production — JSON Logs to File

app.use(requestLogger({
  fields: ['method', 'url', 'status', 'duration', 'timestamp', 'ip', 'requestId'],
  format: 'json',
  transports: ['file'],
  filePath: 'logs/production.log',
}));

Debug Mode — Log Everything

app.use(requestLogger({
  fields: [
    'method', 'url', 'route', 'handler', 'status', 'duration', 'timestamp',
    'ip', 'userAgent', 'headers', 'body', 'query', 'params', 'requestId'
  ],
  format: 'json',
  transports: ['console', 'file'],
  filePath: 'logs/debug.log',
}));

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All Options (Cheat Sheet)

app.use(requestLogger({
  fields: [...],              // which fields to log
  format: 'default' | 'json', // how it looks
  transports: ['console', 'file'], // where it goes
  filePath: 'logs/app.log',   // file to write to
  colors: true,               // turn colors on/off (auto by default)
  skip: (req, res) => false,  // skip certain requests
  requestIdHeader: 'x-request-id', // header name for IDs (or false to disable)
  generateRequestId: () => '...',  // your own ID generator
}));

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TypeScript

Works out of the box. All types are exported:

import { requestLogger, LoggerOptions, LogField } from 'backend-logger';

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Requirements

• Node.js 16 or newer
• Express 4 or newer

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License

MIT — see LICENSE file for details.

Issues & Feedback

Found a bug? Have an idea? Open an issue.