Browser tests can be created either as single step browser tests or as multistep browser tests. In the first case, the script is created on the fly based on a URL and does not have the ability to send user credentials. In the second case, a script is created using the Recorder and uploaded to Synthetic Classic via a web service. The script may include authentication steps, where a username and password are passed to a web form. The username and password can be parameterized in the script itself, and the parameters can then be updated through the Synthetic Classic Portal. You can also make these updates through the Test Management API.