US ZipCode

Overview

Smarty’s US ZIP Code API returns ZIP-level data — city, state, and coordinates. Auth is Smarty auth-id + token (missing/invalid → 401, verified).

Quick Start

Lookup (replace your credentials):

curl "https://us-zipcode.api.smartystreets.com/lookup?auth-id=YOUR_ID&auth-token=YOUR_TOKEN&zipcode=90210"

[
  {
    "zipcode": "90210",
    "zipcode_type": "S",
    "default_city": "Beverly Hills",
    "county_fips": "06037",
    "state": "CA",
    "latitude": 34.09,
    "longitude": -118.41
  }
]

Authentication

• Register at smarty.com → US ZIP Code API → auth-id + auth-token.
• Send as auth-id and auth-token query params (missing → 401, verified).

Rate Limits & Notes

• Free tier: 250 lookups/month (check the dashboard); paid plans scale.
• Lookup by zipcode or city/state; returns county FIPS and coordinates.

FAQ

Is Smarty US ZIP Code free? Free tier: 250 lookups/month; more is paid.

How do I get credentials? smartystreets.com → create an account → auth-id/token.

Why 401? auth-id/auth-token are required (verified).