The latest articles on DEV Community by Jhony Lucas (@jhonylucas74). https://dev.to/jhonylucas74 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F77%2F7a52aa5c-ccfc-45af-a945-505178c7ac97.png https://dev.to/jhonylucas74 en Jhony Lucas Sun, 10 Aug 2025 13:24:00 +0000 https://dev.to/jhonylucas74/how-to-calculate-distances-between-us-zip-codes-exploring-free-apis-and-a-self-hosted-solution-1gfk https://dev.to/jhonylucas74/how-to-calculate-distances-between-us-zip-codes-exploring-free-apis-and-a-self-hosted-solution-1gfk <h1> How to Calculate Distances Between US ZIP Codes: Exploring Free APIs and a Self-Hosted Solution </h1> <p>Calculating distances between postal codes is a key feature for many applications, whether it’s for delivery route optimization, finding nearby stores, or geo-targeted marketing. For developers working with US ZIP codes, there are several free APIs and approaches you can use to achieve this. However, each comes with its own trade-offs.</p> <p>In this article, we’ll explore popular free APIs to calculate distances between ZIP codes, their limitations, and introduce a self-hosted solution that offers full control and high performance.</p> <h2> Popular Free APIs for ZIP Code Distance Calculation </h2> <h3> Zippopotam.us </h3> <p>Zippopotam.us is a simple, free API that provides geographic information, including latitude and longitude, for ZIP codes across many countries including the US.</p> <ul> <li> <strong>Pros:</strong> No API key needed, easy to use, free. </li> <li> <strong>Cons:</strong> Only provides location data, so you need to calculate the distance yourself using the coordinates.</li> </ul> <p>To calculate the distance, you’d typically fetch latitude and longitude for each ZIP code, then apply the Haversine formula in your code.</p> <h3> GeoNames </h3> <p>GeoNames offers a web service with a variety of geographic data, including postal codes and their distances.</p> <ul> <li> <strong>Pros:</strong> Provides a dedicated <code>postalCodeDistance</code> API endpoint to calculate distances directly. </li> <li> <strong>Cons:</strong> Requires free registration, has usage limits (thousands of requests per day).</li> </ul> <p>It’s a good option if you want a ready-made distance calculation without building your own logic.</p> <h3> OpenStreetMap &amp; Nominatim </h3> <p>OpenStreetMap’s Nominatim service offers geocoding, turning ZIP codes into lat/long coordinates.</p> <ul> <li> <strong>Pros:</strong> Free and open source data. </li> <li> <strong>Cons:</strong> No direct distance calculation; you have to implement it. Usage limits apply if you use the public server, so hosting your own instance might be necessary for heavy use.</li> </ul> <h3> Google Maps Distance Matrix API </h3> <p>Google’s Distance Matrix API calculates distances and travel times between multiple points.</p> <ul> <li> <strong>Pros:</strong> Very accurate routing distances, handles driving, walking, and transit modes. </li> <li> <strong>Cons:</strong> Requires billing account and API key, free tier has monthly usage limits, and depends on an external service.</li> </ul> <p>This is best if you need real-world travel distances instead of straight-line distances.</p> <h2> The Challenge with Free APIs </h2> <p>While these free options are great to get started or for small projects, they can come with limitations:</p> <ul> <li>Rate limits and quotas that restrict usage. </li> <li>External dependencies can add latency and reliability issues. </li> <li>Privacy concerns when sending user location data to third parties. </li> <li>Complexity if you have to combine multiple services or implement your own distance calculations.</li> </ul> <h2> Introducing US Zip Distance API: A Fast, Reliable, Self-Hosted Alternative </h2> <p>To overcome these challenges, I developed the <strong>US Zip Distance API</strong>, a lightweight TypeScript REST API that calculates distances between US ZIP codes using an embedded SQLite database and the Haversine formula.</p> <ul> <li> <strong>Self-hosted:</strong> Runs entirely on your own infrastructure, no external dependencies or network calls. </li> <li> <strong>Fast:</strong> Millisecond response times ideal for scalable web and mobile applications. </li> <li> <strong>Flexible:</strong> Supports multiple distance units and returns results sorted by proximity. </li> <li> <strong>Easy to deploy:</strong> Dockerized and simple local setup with full source code included.</li> </ul> <p>This approach gives you full control over your data, usage, and scaling. No surprises or hidden limits.</p> <p>After purchase, you receive a ZIP archive with the complete project and clear instructions to get started quickly.</p> <p>If you want to learn more, check it out here:<br><br> <a href="https://jhonylucas74.itch.io/us-zip-distance-api" rel="noopener noreferrer">https://jhonylucas74.itch.io/us-zip-distance-api</a></p> api typescript geolocation selfhosted