Headless Browsers

What are the Headless Browsers?

  • Headless Browsers are the Web Browsers without Head or GUI(Graphical User Interface).
  • i.e. You cannot see anything on your screen, programs run at the backend.
  • Headless Browsers are the software programs that access the web pages but don’t show them to the user.

Why should we use Headless Browsers?

  •     Running your test on a headless system like Linux OS on GUI.
  •     When you want to simulate multiple browser behaviour on a single machine.
  •     To use minimal resources because there is no GUI.
  •     Need to your run test just for data connection.

When should we NOT use Headless Browsers

  •       If you need to visually observe your test on the browser.
  •         It doesn’t give you exact feedback of what your customer will actually experience on your website. (Page loading Speeds.. etc)
  •        Headless Browsers  sometimes may throw errors that are not observed on real browsers


Examples of Headless Browsers

  1. Firefox Headless Mode:

With the launch of version 56 of Firefox, Mozilla began offering support for headless testing. Instead of using other tools to simulate browser environments, developers can now connect several different APIs to run Firefox in headless mode and test a variety of use cases.

  2. Headless Chrome:

Developers familiar with Chrome can launch version 59 or later in headless mode to utilize all the possibilities afforded by Chromium and the Blink rendering engine.

  3. PhantomJS:

Complexity is commonplace in the modern internet landscape, and PhantomJS is built to handle it all using basic command line testing. This headless WebKit is scriptable via the JavaScript API and uses CasperJS to handle testing. Capable of simulating “full navigation scenarios,” PhantomJS can reveal all the places where a user may encounter errors while browsing.

  4. HtmlUnit:

Written in Java, HtmlUnit allows you to use Java code to automate many of the basic ways in which users interact with websites.


Headless browsers can benefit the developers in many ways. In this blog post, we were able to showcase some popular features of various browsers, which provide the option of headless. Talking about the trends, Phantom JS is the most popular headless browser as of now. One can still choose from the variety of other options available according to respective needs.


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