The tool base URL is used to match tool launch URLs to the correct tool configuration. Prefixing the URL with http(s) is optional.

Additionally, the base URL is used as the launch URL if a launch URL is not specified in the external tool instance.

For example, a base URL of *tool.com* would match the following:

* tool.com
* tool.com/quizzes
* tool.com/quizzes/quiz.php?id=10
* www.tool.com/quizzes

A base URL of *www.tool.com/quizzes* would match the following:

* www.tool.com/quizzes
* tool.com/quizzes
* tool.com/quizzes/take.php?id=10

A base URL of *quiz.tool.com* would match the following:

* quiz.tool.com
* quiz.tool.com/take.php?id=10

If two different tool configurations are for the same domain, the most specific match will be used.