A node.js command line app for packing Google Chrome extensions.
Switch branches/tags
Nothing to show
Pull request Compare This branch is 1 commit ahead, 125 commits behind oncletom:master.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.



Build Status

crx is a node.js command line app for packing Google Chrome extensions.


  • node.js, tested with 0.4.12
  • openssl
  • ssh-keygen
  • zip


$ npm install crx

Module API

ChromeExtension = require("crx")

crx = new ChromeExtension(attrs)

This module exports the ChromeExtension constructor directly, which can take an optional attribute object, which is used to extend the instance.

crx.load(path, callback)

Loads the Chrome Extension from the specified path.


Packs the Chrome Extension, and calls back with a Buffer containing the .crx file.


Returns a Buffer containing the update.xml file used for autoupdate, as specified for update_url in the manifest. In this case, the instance must have a property called codebase.


Destroys all of the temporary resources used for packing.

Module example

var fs = require("fs")
  , ChromeExtension = require("crx")
  , crx = new ChromeExtension(
      codebase: "http://localhost:8000/myFirstExtension.crx",
      privateKey: fs.readFileSync(__dirname + "/key.pem"),
      rootDirectory: __dirname + "/myFirstExtension"

crx.load(function(err) {
  if (err) throw err

  this.pack(function(err, data){
    if (err) throw err

    var updateXML = this.generateUpdateXML()

    fs.writeFile(__dirname + "/update.xml", updateXML)
    fs.writeFile(__dirname + "/myFirstExtension.crx", data)


crx pack [directory] [-f file] [-p private-key]

Pack the specified directory into a .crx package, and output it to stdout. If no directory is specified, the current working directory is used.

Use the -f option to output to a file instead of stdout; if no file is specified, the package is given the same name as the directory basename.

Use the -p option to specify an external private key. If this is not used, key.pem is used from within the directory. If this option is not used and no key.pem file exists, one will be generated automatically.

Use the -b option to specify the maximum buffer allowed to generate extension. By default, will rely on node internal setting (~200KB).

crx keygen [directory]

Generate a 1,024-bit RSA private key within the directory. This is called automatically if a key is not specified, and key.pem does not exist.

crx -h

Show information about using this utility, generated by commander.

CLI example

Given the following directory structure:

└─┬ myFirstExtension
  ├── manifest.json
  └── icon.png

run this:

cd myFirstExtension
crx pack -f

to generate this:

├─┬ myFirstExtension
│ ├── manifest.json
│ ├── icon.png
│ └── key.pem
└── myFirstExtension.crx

You can also name the output file like this:

cd myFirstExtension
crx pack -f myFirstExtension.crx

to get the same results, or also pipe to the file manually like this.

cd myFirstExtension
crx pack > ../myFirstExtension.crx

As you can see a key is generated for you at key.pem if none exists. You can also specify an external key. So if you have this:

├─┬ myFirstExtension
│ ├── manifest.json
│ └── icon.png
└── myPrivateKey.pem

you can run this:

crx pack myFirstExtension -p myPrivateKey.pem -f

to sign your package without keeping the key in the directory.


Copyright (c) 2012 Jed Schmidt. See LICENSE.txt for details.

Send any questions or comments here.