PostalCodes API

Overview

PostalCodes provides a set of APIs focused on postal code data, geocoding, and reverse geocoding services. It is designed to assist developers in integrating location-based functionalities into applications that require precise postal information. The platform offers capabilities to look up postal codes, convert geographical coordinates into postal addresses, and perform radius-based searches for specific areas. This makes it suitable for applications that need to validate addresses, determine service areas, or offer location-aware features primarily driven by postal data.

The API is particularly useful for small applications or projects that require basic, reliable postal code data without the complexity of more extensive GIS platforms. Its core offerings include a dedicated Zip Code API for direct lookups, a Reverse Geocoding API for coordinate-to-postal-code conversions, and a Zip Code Radius Search for defining geographical boundaries based on a central postal code. Additionally, it offers a Country Data API, which can provide generalized information related to postal systems in various regions.

Developers using PostalCodes can expect a clear developer experience, with documentation that emphasizes common use cases and provides direct examples. The service operates on a freemium model, offering a free tier for up to 1,000 requests per day, which allows for initial development and testing without immediate financial commitment. This approach positions PostalCodes as an accessible option for developers seeking to integrate fundamental geospatial capabilities focused on postal code resolution and management.

While some geocoding services offer advanced features like routing, place search, or elevation data, PostalCodes maintains a narrower focus. This specialization allows it to provide a streamlined solution for its specific domain of postal code and basic location data. For applications where the primary geospatial requirement is the accurate handling and querying of postal codes, PostalCodes aims to provide a reliable and efficient service. Its utility extends to e-commerce platforms requiring shipping validation, logistics systems defining delivery zones, or any application where a postal code serves as a primary geographical identifier.

Key features

• Zip Code API: Allows developers to perform direct lookups for postal codes, retrieving associated geographical data such as city, state, and coordinates.
• Reverse Geocoding API: Converts latitude and longitude coordinates into the corresponding postal code and address information. This is useful for identifying the postal area of a given location.
• Zip Code Radius Search: Enables the retrieval of all postal codes within a specified radius (e.g., in kilometers or miles) from a central postal code, supporting localized service area definitions.
• Country Data API: Provides general information about postal code formats and systems for various countries globally, aiding in international address validation.
• Address Validation (Basic): Assists in verifying the existence and format of postal codes, contributing to data accuracy for shipping and billing.
• JSON and XML Support: API responses are available in both JSON and XML formats, allowing developers to choose the data representation that best fits their application's needs.
• Developer-Friendly Documentation: Offers straightforward documentation with practical examples for common integration scenarios, aiming for a simple developer experience with its postal code and basic location data focus.

Pricing

PostalCodes offers a free tier and various paid plans. Pricing is effective as of May 2026.

For detailed pricing information and current offerings, refer to the official PostalCodes pricing page.

Common integrations

• E-commerce platforms: Integrate for shipping address validation and calculating shipping zones based on postal codes.
• Logistics and delivery services: Use for optimizing delivery routes and defining service areas by leveraging postal code radius searches.
• CRM systems: Enhance customer data with accurate geographical information linked to postal codes.
• Real estate applications: Power property searches and market analysis based on specific postal districts.
• Mapping applications: Augment maps with postal code overlays or reverse geocoding capabilities.

Alternatives

• OpenCage Geocoding API: Offers global geocoding and reverse geocoding, often citing open data sources.
• Geoapify Geocoding API: Provides geocoding, reverse geocoding, and autocomplete features with a focus on ease of use.
• LocationIQ: Specializes in geocoding, reverse geocoding, and routing, built on OpenStreetMap data.
• Google Maps Geocoding API: A comprehensive geocoding service part of the Google Cloud platform, offering high accuracy and global coverage for converting addresses to coordinates and vice versa.
• Amazon Location Service: Provides geocoding, routing, tracking, and mapping capabilities, integrated with AWS services.

Getting started

To get started with the PostalCodes API, you typically make an HTTP GET request to their endpoints with your API key. Here's an example of how to perform a basic postal code lookup using Python:

import requests

API_KEY = "YOUR_API_KEY" # Replace with your actual API key
POSTAL_CODE = "90210"   # Example postal code

def lookup_postal_code(api_key, postal_code):
    base_url = "https://api.postalcodes.net/v1/" # Check official docs for current base URL
    endpoint = f"postalcode/{postal_code}"
    params = {
        "key": api_key
    }
    
    try:
        response = requests.get(f"{base_url}{endpoint}", params=params)
        response.raise_for_status() # Raise an HTTPError for bad responses (4xx or 5xx)
        data = response.json()
        
        if data and data.get("success"):
            print(f"Postal Code: {postal_code}")
            print(f"City: {data['data']['city']}")
            print(f"State: {data['data']['state']}")
            print(f"Latitude: {data['data']['latitude']}")
            print(f"Longitude: {data['data']['longitude']}")
        else:
            print(f"Error or no data found: {data.get('message', 'Unknown error')}")
            
    except requests.exceptions.HTTPError as http_err:
        print(f"HTTP error occurred: {http_err}")
    except requests.exceptions.ConnectionError as conn_err:
        print(f"Connection error occurred: {conn_err}")
    except requests.exceptions.Timeout as timeout_err:
        print(f"Timeout error occurred: {timeout_err}")
    except requests.exceptions.RequestException as req_err:
        print(f"An error occurred: {req_err}")

if __name__ == "__main__":
    lookup_postal_code(API_KEY, POSTAL_CODE)

Before running this code, ensure you replace "YOUR_API_KEY" with your actual API key obtained from the PostalCodes website after registration. The example demonstrates how to construct a request, handle the JSON response, and print relevant geographical data. For more advanced features like reverse geocoding or radius searches, consult the official PostalCodes API documentation.