c# - Nearest Zip Code Search using asp.net

Question

I want to inplement functionallity that will search zip codes, if user enter any zip code than all the zip codes close to entered zip code will be shown. Please let us know if there is any free api for it like Google API or any other solutions.

Answer 1

First, grab a free zip code database like this one. This will allow you to convert from an entered zip code to a latitude and longitude. As long as you make latitude and longitude database keys also, you can now look up all the nearby latitudes and longitudes (by moving up and down in the sorted values) and get all ZIP codes within a desired distance.

Here is an example of how to calculate latitude and longitude distances.