While the vast majority of tree testing is done online using dedicated tree-testing software, you can also test on paper (the original medium) or by using alternative (usually free) methods.

Testing online with commercial tools

As tree testing has matured as a recognized IA technique, online tools have sprung up to meet demand. All of these tools advantages over doing a tree test manually, such as providing:

Unmoderated testing
People only need a web browser to participate - anywhere and any time, without you having to be present.
Flexible testing options
As the test administrator, you can customize how the test is run.
Automated analysis
The software records the participants' actions, and helps you analyze the results.

Here's a list of the commercials tools we know of (listed alphabetically), with some basic information on each.

Product	Owner	Pricing starting at...	Summary
~~C-Inspector~~	Steffen Schilb	~~$99/study~~	Introduced in 2008, but discontinued in 2014.
Treejack	Optimal Workshop	$109/month	Introduced in 2008 as a companion to the OptimalSort card-sorting tool.
UserZoom tree-testing module	UserZoom	$19,000/year	Aimed at larger enterprises, the UserZoom suite of tools includes tree testing as a module.

Disclaimer: While most of our experience is with Treejack, we don't recommend a particular product in this guide, because the right product for you will depend on factors such as price, compatibility with other tools you're already using, and specific features you need.

Testing with paper cards

summary of paper testing, links to other paper content in this guide
http://uxmastery.com/testing-information-architecture/
blog.sensenet.com/post/2015/11/13/tree-testing.aspx

Other tools

folder clicking, Dreamweaver site maps, etc. - see B&A article comments, archived emails, etc.

Next: Where will you test?