The original post is a bit dated, but after searching around the web, it seems this is one of those things that still doesn’t have a clear solution- at least not one that’s been shared.
Amen rstevens! We need a zip code field for users to complete that auto-populates hidden fields for city and state.
Cursu, do you mind me asking what API you are using?
I found something that looked promising with ‘Javascript: City/State Auto-Fill’ at https://www.zipcodeapi.com/API - created client and application keys for the solution, edited the JS to include the correct IDs etc, placed the JS in the footer of the page with the form, but nothing.
It would be great to know what I’m doing wrong, or if anyone else has found a way to incorporate ZipCodeAPI into HubSpot.