A headless browser is a browser that does not have a GUI. It is used to simulate programs even though there is no browser installed on the local system. You will not see the browser in your system but will get the RESULT in the CONSOLE. The headless browser does not have GUI means program runs in the background without GUI.

Two headless browsers widely used are HtmlUnitDriver and PhantomJSDriver.

Advantages of performing Headless browser testing -

1. It is faster. Compared to browser automation, performance is better. Running regression scripts using browser takes lots of time, but with headless browsers, time is saved.
2. It allows you to run scripts on a system that does not have a browser.
3. It helps in EXECUTING scripts on different browser versions on the local system even though that browser VERSION is not AVAILABLE on the system. Most of the headless browsers support browser versions.

Disadvantages of Headless browsers testing -

1. Debugging is difficult using headless browsers as the browser is not available. The only way is to capture a screenshot.