All the STEPSTools API methods require an authentication token to be passed as a parameter when calling the method. If a valid token is not passed, the method will return an error message in the XML response. Accounts on pedstep.org with developer privileges can retrieve a valid authentication token from the service using the GetAuthToken method of the service.
To get your authentication token, you will need an account on the site (if you don't already have one) which you can apply for
here. When you apply, be sure to select the checkbox indicating that you are a developer requesting an authentication token.
Someone on the STEPStools team will review and approve the request, and an email will be sent to you when your authentication token is available.
Once you have a token, you can view this page while logged in to you account and your token will be displayed in large boldfaced print near the top for your reference.