Introduction

zipcode_search is a very simple application (bootstrapped via prompt to DeepSeek v4 Pro 0813).

It provides an alternative implementation modeled after the '/radius' enpoint of the API documented at: https://app.zipcodebase.com/documentation

For example:

https://{your domain}/api/v1/radius?apikey=YOUR-APIKEY&code=02134&radius=1&country=us

Note the following potential differences:

• country is ignored
• only a single source zipcode may be specified
• unit is supported (km|mi), default mi
• apikey is supported as a query string, but if provided in a header (X-API-Key) it will be preferred.

Example usage

$ go mod download
$ export API_KEY=secret DUCKDB_PATH=zipsearch.duckdb
$ go run .
$ # Query within 10 miles:
$ curl -H "X-API-Key: secret" \
  "http://localhost:8080/api/v1/radius?code=10001&radius=10&unit=mi"

Database sources

https://www.nber.org/research/data/zip-code-distance-database

Using duckdb cli, you can load the database as follows (using the 50 mile db):

$ duckdb zipsearch.duckdb
zipsearch D create table zip_distance (zip1 varchar, zip2 varchar, distance float);
zipsearch D insert into zip_distance (zip1, zip2, distance) select zip1, zip2, miles_to_zcta5 from 'gaz2024zcta5distance50miles.csv';
zipsearch D .exit