Below are a number of options for the Webdriver service. Nightwatch can start and stop the Webdriver process automatically which is very convenient as you don't have to manage this yourself and focus only on the tests.

If you'd like to enable this, set start_process to true and specify the location of the binary file inside server_path.

Name type default description
start_process boolean false When this is enabled, the Webdriver server is run in background in a child process and started/stopped automatically.
Nightwatch includes support for managing Chromedriver, Geckodriver (Firefox), Safaridriver, and Selenium Server.
server_path string none Only useful if start_process is enabled.
host string Only needed when the Webdriver service is running on a different machine.
port integer The port number on which the Webdriver service will listen and/or on which Nightwatch will attempt to connect.
ssl boolean Should be set to true if connecting to a remote (cloud) service via HTTPS. Also don't forget to set port to 443.
log_path string|boolean none The location where the Webdriver service log file output.log file will be placed. Defaults to current directory.
To disable Webdriver logging, set this to false
log_file_name string|none none By default, the log file name will be the same as the testsuite file name, but a different filename can be specified as well.
cli_args object none List of cli arguments to be passed to the Webdriver process. This varies for each Webdriver implementation.
keep_alive boolean|object false Enable HTTP Keep-Alive. If set to true the keepAlive option is enabled with default settings (keepAliveMsecs = 3000).
If set to an object, can specify specify the keepAliveMsecs value.

Example: "keep_alive" : {"enabled" : true, "keepAliveMsecs" : 2000}
timeout_options object timeout: 60000
retry_attempts: 0
Requests to the Webdriver service will timeout in timeout miliseconds; a retry will happen retry_attempts number of times.

{timeout: 15000, retry_attempts: 5}
since v1.2.2
integer 100 Interval (in ms) to use between status ping checks when checking if the Webdriver server is up and running
since v1.2.2
integer 5 Maximum number of ping status check attempts when checking if the Webdriver server is up and running before returning a timeout error.
since v1.2.2
integer 120000 The entire time (in ms) to wait for the Node.js process to be created and running (default is 2 min), including spawning the child process and checking the status
username string none Usually only needed for cloud testing Selenium services. In case the server requires credentials this username will be used to compute the Authorization header.

The value can be also an environment variable, in which case it will look like this:
"username" : "${SAUCE_USERNAME}"
access_key string none This field will be used together with username to compute the Authorization header.

Like username, the value can be also an environment variable:
"access_key" : "${SAUCE_ACCESS_KEY}"
proxy string none Proxy requests to the Webdriver (or Selenium) service. http, https, socks(v5), socks5, sock4, and pac are accepted.
Uses proxy-agent which needs to be installed as a separate package from NPM.

Example: http://user:pass@host:port
default_path_prefix string Needed sometimes when using a Selenium Server. The prefix to be added to to all requests (e.g. /wd/hub).