Zip Code API — Free Postal Code Search & Validation (zipcodestack.com)

Build with the Zip Code API from zipcodestack.com to validate postal codes, search global ZIP/postal codes, and calculate distances between areas. This README is optimized for developers looking for a fast, reliable, and free-tier friendly zip code API.

Links:

• Get an API Key: zipcodestack.com
• Full API Documentation: zipcodestack.com/docs

Table of Contents

• Overview
• Why This Zip Code API
• Quickstart
• Endpoints
  • Search Endpoint
  • Distance Endpoint
• Authentication
• Rate Limits & Quotas
• Usage Examples
• Use Cases
• FAQ Snapshot
• Support & Contact

Overview

The zipcodestack Zip Code API provides real-time validation and information about global postal codes. With worldwide coverage and frequent updates, it’s ideal for address validation, checkout flows, and logistics distance calculations.

Reference: zipcodestack.com, API Docs

Why This Zip Code API

• Global coverage with regularly updated data
• Easy-to-use REST API and SDKs
• Fast response times suitable for production
• Generous free tier to get started quickly
• Priority support and straightforward scaling options

Quickstart

1. Sign up and get your API key: zipcodestack.com
2. Make your first request using your apikey header (or apikey query parameter).

Example (cURL):

curl -X GET \
  --url "https://api.zipcodestack.com/v1/search?codes=20095&country=de" \
  --header "apikey: YOUR-APIKEY"

Endpoints

Search Endpoint

Search for one or multiple zip/postal codes globally or within a specific country.

• Method: GET
• Path: /v1/search
• Query parameters:
  • codes (required) — one or more postal codes (comma-separated)
  • country (optional) — ISO 2 country code to scope the search

Example:

curl -X GET \
  --url "https://api.zipcodestack.com/v1/search?codes=20095&country=de" \
  --header "apikey: YOUR-APIKEY"

Distance Endpoint

Calculate the distance between two zip/postal codes.

• Method: GET
• Path: /v1/distance
• Query parameters:
  • code (required) — the origin postal code
  • compare (required) — the destination postal code

Example:

curl -X GET \
  --url "https://api.zipcodestack.com/v1/distance?code=99501&compare=90210" \
  --header "apikey: YOUR-APIKEY"

See full parameter options and response formats in the official docs: zipcodestack.com/docs

Authentication

Provide your API key via HTTP header or query parameter.

• Header (recommended): apikey: YOUR-APIKEY
• Query parameter (alternative): ?apikey=YOUR-APIKEY

Details: Authentication guide

Rate Limits & Quotas

Rate limits vary by plan and are subject to change. Review the current limits and quota behavior in the docs: Rate Limit & Quotas

Usage Examples

JavaScript (fetch)

const apiKey = process.env.ZIPCODESTACK_API_KEY;

async function searchZipCodes() {
  const res = await fetch(
    "https://api.zipcodestack.com/v1/search?codes=90210&country=us",
    { headers: { apikey: apiKey } }
  );
  if (!res.ok) throw new Error(`Request failed: ${res.status}`);
  const data = await res.json();
  return data;
}

async function distanceBetween() {
  const res = await fetch(
    "https://api.zipcodestack.com/v1/distance?code=99501&compare=90210",
    { headers: { apikey: apiKey } }
  );
  if (!res.ok) throw new Error(`Request failed: ${res.status}`);
  return res.json();
}

Node.js (axios)

const axios = require("axios");

async function searchZipCodes() {
  const { data } = await axios.get(
    "https://api.zipcodestack.com/v1/search",
    {
      params: { codes: "20095", country: "de" },
      headers: { apikey: process.env.ZIPCODESTACK_API_KEY },
    }
  );
  return data;
}

Python (requests)

import os
import requests

API_KEY = os.getenv("ZIPCODESTACK_API_KEY")

def search_zip_codes():
    url = "https://api.zipcodestack.com/v1/search"
    params = {"codes": "90210", "country": "us"}
    headers = {"apikey": API_KEY}
    r = requests.get(url, params=params, headers=headers, timeout=10)
    r.raise_for_status()
    return r.json()

def distance_between():
    url = "https://api.zipcodestack.com/v1/distance"
    params = {"code": "99501", "compare": "90210"}
    headers = {"apikey": API_KEY}
    r = requests.get(url, params=params, headers=headers, timeout=10)
    r.raise_for_status()
    return r.json()

Use Cases

• Address and ZIP code validation
• E-commerce checkout address normalization
• Shipping distance and zone calculations
• Data enrichment for user profiles and CRM

FAQ Snapshot

According to the site and documentation, the service provides:

• Real-time validation and information about postal codes
• Regular database updates sourced from official services
• Simple authentication with API key

For more details and the latest specifics, see:

• Website: zipcodestack.com
• Documentation: zipcodestack.com/docs

Support & Contact

If you have questions about integrating the Zip Code API or need higher limits, visit the site or contact support via the links in the footer:

• zipcodestack.com
• API Documentation