I've had a client approach me to develop an application that would interface with an existing web API.
Normally my perspective is that the freelancer shouldn't bill the client for any time spent learning common tools. However, the existing web API the client wants to access is a specialty API and is only useful in specialty applications. I don't expect I would ever need the API again, and I am highly doubtful that the client will find another freelancer that is already familiar with the API.
What is the normal thing to do in such a situation? Do I include the time spent learning specialty tools in my proposal for the project, silently bump up the rate, or something else?