A port of log4js to node.js

View the Project on GitHub


This is a conversion of the log4js framework to work with node. I started out just stripping out the browser-specific code and tidying up some of the javascript to work better in node. It grew from there. Although it’s got a similar name to the Java library log4j, thinking that it will behave the same way will only bring you sorrow and confusion.

Changes in version 3.x

Migrating from log4js < v2.x?

There have been a few changes between log4js 1.x and 2.x (and 0.x too). You should probably read this migration guide if things aren’t working.



npm install log4js


Minimalist version:

var log4js = require("log4js");
var logger = log4js.getLogger();
logger.level = "debug"; // default level is OFF - which means no logs at all.
logger.debug("Some debug messages");


If you use node’s cluster, or passenger, or pm2, then you should read this clustering guide

Note for library makers

If you’re writing a library and would like to include support for log4js, without introducing a dependency headache for your users, take a look at log4js-api.


The original log4js was distributed under the Apache 2.0 License, and so is this. I’ve tried to keep the original copyright and author credits in place, except in sections that I have rewritten extensively.