This is mainly a wrapper to OSM's Nominatim. However, we add other logic (e.g. bounding box, name near) and data (postcodes, station codes), so please use our geocoder interface rather than Nominatim directly, for consistency.
Please ensure you comply with the Nominatim Usage Policy. Normal bona-fide use should be perfectly compliant.
Example: Thoday Street
returns a list of results, including the name, latitude, longitude and where it is 'near'.
If the boundaries are supplied, then the geocoder will tend to prefer results in this part and near surrounding parts of the country when the zoom is 12 or higher (this logic may change in future to be zoom-agnostic if the bounding box is sent).
Sending z= will be treated as zoom= . z= is now deprecated and will be disabled in due course.