To help improve the performance and availability of our API services, MapQuest is moving to a cloud-based infrastructure. As part of this move we are retiring several older legacy services that are no longer widely used. This includes the Xapi API service.
On October 31, 2016 we’re retiring the Xapi open API service. This is an older OpenStreetMap open source API that is no longer supported in the open source community, and we recommend anyone still using Xapi move to the open source Overpass API service. MapQuest does not offer the Overpass API, check the OpenStreetMap wiki below for sources.
The Overpass API includes a powerful query language with with a much more robust feature set compared to the former Xapi based tools. Also, the Overpass API provides a compatibility layer that allows a smooth transition from Xapi.For details on XAPI and Overpass view the OpenStreetMap wiki entry on Xapi and the Overpass wiki entry.