Geckodriver

An npm wrapper for Mozilla's Geckodriver. It manages to download various (or the latest) Geckodriver versions and provides a programmatic interface to start and stop it within Node.js. Note: this is a wrapper module. If you discover any bugs with Geckodriver, please report them in the official repository.

Requirements: Node.js 22.19.0 or newer. With Yarn and without WebdriverIO, also install @wdio/logger. See Compatibility.

Installing

You can install this package via:

npm install geckodriver

Or install it globally:

npm install -g geckodriver

Note: This installs a geckodriver shell script that runs the executable, but on Windows, selenium-webdriver looks for geckodriver.exe. The package downloads the binary into its cache folder (GECKODRIVER_CACHE_DIR, by default the system temporary folder) as geckodriver-<version>.exe, not into the package folder. Set the cache folder and the version, run the driver once, then copy the binary to a folder on your PATH (such as the npm bin directory):

set GECKODRIVER_CACHE_DIR=%USERPROFILE%\geckodriver
set GECKODRIVER_VERSION=0.37.1
geckodriver --version
copy /Y %GECKODRIVER_CACHE_DIR%\geckodriver-%GECKODRIVER_VERSION%.exe %APPDATA%\npm\geckodriver.exe

Name the exact version: with a wildcard, copy joins all cached versions into one broken file.

Once installed you can start Geckodriver via:

npx geckodriver --port=4444

By default, this package downloads Geckodriver when used for the first time through the CLI or the programmatic interface. If you like to download it as part of the npm install process, set the GECKODRIVER_AUTO_INSTALL environment flag, e.g.:

GECKODRIVER_AUTO_INSTALL=1 npm i

The download runs in the package's postinstall script. pnpm 10 or newer and Bun run it only for a package you approve (pnpm approve-builds, or trustedDependencies in Bun), and recent npm versions warn until you approve it with npm install-scripts approve geckodriver. If the download fails, the install does not fail: the driver then downloads on first use.

To get a list of available CLI options run npx geckodriver --help. By default, this package downloads the latest version of the driver. If you prefer to have it install a custom Geckodriver version you can define the environment variable GECKODRIVER_VERSION when running in CLI, e.g.:

$ npm i geckodriver
$ GECKODRIVER_VERSION="0.31.0" npx geckodriver --version
geckodriver 0.31.0 (b617178ef491 2022-04-06 11:57 +0000)

The source code of this program is available from
testing/geckodriver in https://hg.mozilla.org/mozilla-central.

This program is subject to the terms of the Mozilla Public License 2.0.
You can obtain a copy of the license at https://mozilla.org/MPL/2.0/.

Setting a CDN URL for binary download

To set an alternate CDN location for Geckodriver binaries, set the GECKODRIVER_CDNURL like this:

GECKODRIVER_CDNURL=https://INTERNAL_CDN/geckodriver/download

Binaries on your CDN should be located in a subdirectory of the above base URL. For example, /vxx.xx.xx/*.tar.gz should be located under /geckodriver/download above.

Alternatively, add it to your .npmrc file:

geckodriver_cdnurl=https://INTERNAL_CDN/geckodriver/download

The default location is set to https://github.com/mozilla/geckodriver/releases/download

A CDN URL can carry credentials, for example https://user:password@INTERNAL_CDN: they are sent as a Basic Authorization header and kept out of the logs. Percent-encode special characters in them (@ is %40, % is %25). Use an https:// URL: over http://, Basic credentials travel in clear text. A redirect to another host does not receive them.

Setting a PROXY URL

Use HTTPS_PROXY or HTTP_PROXY to set your proxy URL, and NO_PROXY for the hosts that skip it. The lower-case forms (https_proxy, http_proxy, no_proxy) work too and win over the upper-case ones. A dispatcher set with undici's setGlobalDispatcher (as in the WebdriverIO proxy docs) wins over these variables.

Programmatic Interface

You can import this package with Node.js and start the driver as part of your script and use it e.g. with WebdriverIO.

Exported Methods

The package exports a start and download method.

start

Starts a Geckodriver instance and returns a ChildProcess. If Geckodriver is not downloaded it will download it for you.

The driver writes logs to its stdout and stderr. Read them, or pass spawnOpts: { stdio: 'ignore' }: an unread pipe fills up and then blocks the driver.

Params: GeckodriverParameters - options to pass into Geckodriver (see below)

Example:

import { start } from 'geckodriver';
import { remote } from 'webdriverio';
import waitPort from 'wait-port';

/**
 * first start Geckodriver
 */
const cp = await start({ port: 4444 });

/**
 * wait for Geckodriver to be up
 */
await waitPort({ port: 4444 });

/**
 * then start WebdriverIO session on that port: without `port`, WebdriverIO starts a driver of its own.
 * Geckodriver accepts `127.0.0.1` but not `localhost` (the default) unless you pass `allowHosts`.
 */
const browser = await remote({ hostname: '127.0.0.1', port: 4444, capabilities: { browserName: 'firefox' } });
await browser.url('https://webdriver.io');
console.log(await browser.getTitle()); // prints "WebdriverIO · Next-gen browser and mobile automation test framework for Node.js | WebdriverIO"

/**
 * kill Geckodriver process
 */
cp.kill();

Note: as you can see in the example above this package does not wait for the driver to be up, you have to manage this yourself through packages like wait-port.

download

Method to download a Geckodriver with a particular version. If a version parameter is omitted it tries to download the latest available version of the driver.

Params: string - version of Geckodriver to download (optional)

CJS Support

In case your module uses CJS you can use this package as follows:

const { start } = require('geckodriver')
// see example above

Options

The start method offers the following options to be passed on to the actual Geckodriver CLI.

allowHosts

List of host names to allow. By default, the value of --host is allowed, and in addition, if that's a well-known local address, other variations on well-known local addresses are allowed. If --allow-hosts is provided only exactly those hosts are allowed.

Type: string[] Default: []

allowOrigins

List of request origins to allow. These must be formatted as scheme://host:port. By default, any request with an origin header is rejected. If --allow-origins is provided then only exactly those origins are allowed.

Type: string[] Default: []

binary

Path to the Firefox binary.

Type: string

connectExisting

Connect to an existing Firefox instance.

Type: boolean Default: false

host

Host IP to use for WebDriver server.

Type: string Default: 0.0.0.0

jsdebugger

Attach browser toolbox debugger for Firefox.

Type: boolean Default: false

log

Set Gecko log level [possible values: fatal, error, warn, info, config, debug, trace].

Type: string

logNoTruncate

Log verbosely and don't truncate long strings so that the log can be replayed.

Type: boolean

marionetteHost

Host to use to connect to Gecko.

Type: string Default: 127.0.0.1

marionettePort

Port to use to connect to Gecko.

Type: number Default: 0

port

Port to listen on.

Type: number

websocketPort

Port to use for Debugger / WebDriver BiDi. If omitted and connectExisting is not set, it defaults to 0 (a random available port) rather than Geckodriver's native default, so that parallel instances don't collide. Setting websocketPort together with connectExisting: true throws an error, since the two options can't be used together.

Type: number

profileRoot

Directory in which to create profiles. Defaults to the system temporary directory.

Type: string

geckoDriverVersion

A version of Geckodriver to start. See https://github.com/mozilla/geckodriver/releases for all available versions, platforms and architecture.

Type: string

customGeckoDriverPath

Don't download Geckodriver, instead use a custom path to it, e.g. a cached binary.

Type: string Default: process.env.GECKODRIVER_PATH

cacheDir

The path to the root of the cache directory.

Type: string Default: process.env.GECKODRIVER_CACHE_DIR || os.tmpdir()

spawnOpts

Options to pass into the geckodriver process. This can be useful if needing Firefox to spawn with MOZ_ prefix variables, such as MOZ_HEADLESS_WIDTH. See https://nodejs.org/api/child_process.html#child_processspawncommand-args-options for all options. Pass { stdio: 'ignore' } if you don't read the driver output.

Type: SpawnOptions Default: undefined

Other Browser Driver

If you also look for other browser driver npm wrappers, you can find them here:

• Chrome: giggio/node-chromedriver
• Microsoft Edge: webdriverio/driver - node-edgedriver
• Safari: webdriverio/driver - node-safaridriver

For more information on WebdriverIO see the homepage.