Yep MapKit JS for "find your nearest location" type functionality on a corporate website (with zip/post code lookup, location details overlaid etc.) Rereading

Yep MapKit JS for "find your nearest location" type functionality on a corporate website (with zip/post code lookup, location details overlaid etc.) Rereading OP I realise the question was about APIs rather than necessarily web-based mapping (which is how I initially had read it)