When you start processing a request, you will obtain an instance of VeriplaceState, normally by calling Open()()(). Callling methods such as RequireLocation()()() updates the properties of the VeriplaceState.

If a request cannot be completed, it throws a subclass of VeriplaceException. The web client defines several new exception classes for non-error conditions that can interrupt the handling of a request: RespondedException, which usually means that the user has been redirected to the Veriplace site, and WaitingException, which means that the application is waiting for an asynchronous request and may wish to display an intermediate status page.