GeckoDriver is a standalone application used to interact with Gecko-based browsers, such as Firefox. It is written in Rust and maintained by Mozilla.

Starting with Firefox 48, GeckoDriver is the only way to automate Firefox, the legacy FirefoxDriver which used to be part of Selenium is no longer supported. Internally it translates the HTTP calls into Marionette, Mozilla's automation protocol built into Firefox.


GeckoDriver can be downloaded from the Releases page on GitHub. Release notes are also available there. Or you can use the geckodriver NPM package as a dependency in your project:

npm install geckodriver --save-dev

Selenium 2.x users are advised to use version v0.9, whereas Selenium 3 users should use the latest version.

Standalone Usage

Nightwatch can manage the GeckoDriver service automatically, as with other WebDriver services, such as ChromeDriver. To use GeckoDriver directly, add this to your nightwatch.json:

  "webdriver": {
    "start_process" : true,
    "server_path": "./bin/geckodriver-0.23",
    "cli_args": [
      "--log", "debug"
    "port": 4444
  "test_settings" : {
    "default" : {
      "desiredCapabilities": {
        "browserName" : "firefox",
        "acceptInsecureCerts": true

Usage with Selenium Server

If you're using GeckoDriver through Selenium Server, simply set the cli argument "webdriver.gecko.driver" to point to the location of the binary file. E.g.:

  "selenium" : {
    "start_process" : true,
    "server_path" : "./bin/selenium-server-standalone-3.{VERSION}.jar",
    "log_path" : "",
    "port" : 4444,
    "cli_args" : {
      "webdriver.gecko.driver" : "./bin/geckodriver"

GeckoDriver can also be used as a standalone application. Usage steps are documented on GitHub:

Command line usage

$ ./bin/geckodriver-0.23 -help
geckodriver 0.23.0

    geckodriver-0.23 [FLAGS] [OPTIONS]

        --connect-existing    Connect to an existing Firefox instance
    -h, --help                Prints help information
        --no-e10s             Start Firefox without multiprocess support (e10s) enabled
    -V, --version             Prints version information
    -v                        Set the level of verbosity. Pass once for debug level logging and twice for trace level logging

    -b, --binary <BINARY>        Path to the Firefox binary, if no binary capability provided
        --log <LEVEL>            Set Gecko log level [values: fatal, error, warn, info, config, debug, trace]
        --marionette-port <PORT> Port to use to connect to gecko (default: random free port)
        --host <HOST>            Host ip to use for WebDriver server (default:
    -p, --port <PORT>            Port to use for WebDriver server (default: 4444)
Firefox Capabilities

GeckoDriver supports a capability named firefoxOptions which takes Firefox-specific preference values. Details are available on the GeckoDriver GitHub page:

Firefox Profile

Specifying the firefox profile can be done by setting the profile property in the firefoxOptions dictionary, as detailed above. This can be the base64-encoded zip of a profile directory and it may be used to install extensions or custom certificates.

Implementation Status

GeckoDriver is not yet feature complete, which means it does not yet offer full conformance with the WebDriver standard or complete compatibility with Selenium. Implementation status can be tracked on the Marionette MDN page.