get maxspeed from lat lon values

I am trying to get the maxspeed of the current road I'm on by sending the location to the OSM API. I don't necessarily need to use a bb, right? I have the http get set as:

Server:Port https://www.overpass-api.de path api/xapi?[maxspeed=] mime type text/xml

I get an in/out error, maybe because I am not entering a location? where do i put the location in gps coordinates?

or what else am i doing wrong?

Thanks for any suggestions. I've been scouring the documentation and can't seem to make heads nor tails of it.