Comparison

Best ZIP code APIs in 2026

Which ZIP code API fits your project? We compared the common options by coverage, features and price.

Updated October 1, 2026 ยท 1 min read

We make zipcodestack, so we are not neutral. Prices are from each provider’s pricing page in October 2026.

Overview

APICoverageStrengthsFree tierEntry plan
zipcodestack149 countries, 7M codesLookup, validate, radius, distance, polygon, reverse geocoding, autocomplete300 requests / month70,000 requests for $34.99
Zipcodebase200+ countriesLookup, radius, distance, city/state search5,000 searches, private use60,000 searches for $45
SmartyUS + international addressesFull address verification, ZIP+4TrialPer-lookup plans
USPS Addresses APIUS onlyOfficial USPS data, ZIP+4, city/stateFree with USPS accountFree (rate limited)
GeoNames~100 countriesFree web services and downloadsFree (credits)Premium on request

zipcodestack’s free and paid plans are listed on the pricing page.

How to choose

  1. US only, official data, low volume: the USPS API.
  2. Full street address verification: Smarty or another address verification provider.
  3. International postal codes with radius and distance search: zipcodestack or Zipcodebase.
  4. Large volumes: compare price per request. zipcodestack’s Large plan includes 2.5 million requests for $159.99 per month.

zipcodestack in one request

curl "https://api.zipcodestack.com/v1/search?codes=10001&country=us" -H "apikey: YOUR-API-KEY"

Head-to-head: zipcodestack vs Zipcodebase.

Frequently asked questions

What is the best free ZIP code API?

For hobby projects, GeoNames' free web services and Zipcodebase's free plan (private use) are generous. zipcodestack's free plan has 300 requests per month and allows commercial use; its paid plans are the cheapest per request in this comparison.

Do I need address validation or just ZIP codes?

If you need to verify full street addresses (deliverability, apartment numbers), use an address verification service such as Smarty or the USPS API. For city/state lookup, distances and radius search by postal code, a ZIP code API is simpler and cheaper.

Postal code API

Get this data in your app

zipcodestack looks up, validates and searches postal codes in 149 countries: city, state, coordinates, distances and radius search, as JSON.

/v1/search documentation International postal code API All documentation

300 free requests every month. No credit card required.

GET https://api.zipcodestack.com/v1/search?codes=10001&country=us

{
  "results": {
    "10001": [{
      "postal_code": "10001",
      "country_code": "US",
      "latitude": 40.7484,
      "longitude": -73.9967,
      "city": "New York",
      "state": "New York",
      "state_code": "NY",
      "province": "New York"
    }]
  }
}

Keep reading

Distance between ZIP codes in ExcelCalculate miles or kilometres between ZIP codes in Excel and Google Sheets with the Haversine formula, or fetch distances directly with the WEBSERVICE function. How to validate postal codesPostal code regex patterns for the US, UK, Canada, Germany and 16 more countries, code examples in JavaScript, Python and PHP, and when a regex is not enough. ZIP code database vs APIShould you download a ZIP code database (CSV) or use a ZIP code API? Compare cost, freshness, coverage, maintenance and performance, with recommendations by use case. zipcodestack vs ZipcodebaseLooking for a Zipcodebase alternative? Compare zipcodestack and Zipcodebase: price per request, free tiers, radius limits and endpoints.

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