US ZIP Code Lookup API — Fast, Reliable, Free to Start
Access 42,000+ US ZIP codes via a simple REST API. Get city, state, county, latitude/longitude, and timezone in milliseconds. Used by developers since 2007 — powering real-world applications and data pipelines.
Built for developers, SaaS apps, eCommerce platforms, logistics systems, and data teams.
# Look up a ZIP code curl https://api.zipcodestogo.com/v1/zip/90210 \ -H "X-Api-Key: zcg_your_key_here" # Response { "zip": "90210", "data": { "city": "Beverly Hills", "state": "CA", "county": "Los Angeles", "lat": 34.0901, "lng": -118.4065, "timezone": "America/Los_Angeles" } }
# Find ZIP codes by city name curl https://api.zipcodestogo.com/v1/city?name=Austin&state=TX \ -H "X-Api-Key: zcg_your_key_here" # Response { "city": "Austin", "state": "TX", "zips": [ { "zip": "78701", "lat": 30.2672, "lng": -97.7431 }, { "zip": "78702", "lat": 30.2571, "lng": -97.7217 } ] }
# Find all ZIPs within 10 miles of a ZIP code (Basic+ plans) curl https://api.zipcodestogo.com/v1/radius?zip=10001&miles=10 \ -H "X-Api-Key: zcg_your_key_here" # Response { "origin_zip": "10001", "radius_miles": 10, "results": [ { "zip": "10002", "city": "New York", "distance_miles": 1.4 }, { "zip": "10003", "city": "New York", "distance_miles": 1.9 } ] }
Enter any US ZIP code — no API key needed:
Live request to the API — same response your app will receive. Get an API key to use in production.
- ZIP code lookup
- City & state
- Lat / lng
- City search
- Radius search
- Timezone data
- Population data
No credit card required
- ZIP code lookup
- City, state, county
- Lat / lng
- City search
- Radius search
- Timezone data
- Population data
Cancel anytime
- ZIP code lookup
- City, state, county
- Lat / lng
- City search
- Radius search
- Timezone data
- Population data
Cancel anytime
- ZIP code lookup
- City, state, county
- Lat / lng
- City search
- Radius search
- Timezone data
- SLA + bulk export
Cancel anytime
| Feature | Free | Basic | Pro | Enterprise |
|---|---|---|---|---|
| ZIP code lookup | ✓ | ✓ | ✓ | ✓ |
| City, state, county | ✓ | ✓ | ✓ | ✓ |
| Latitude / longitude | ✓ | ✓ | ✓ | ✓ |
| City search | ✓ | ✓ | ✓ | ✓ |
| Radius search | — | ✓ | ✓ | ✓ |
| Timezone / DST | — | — | ✓ | ✓ |
| Population data | — | — | ✓ | ✓ |
| Bulk export | — | — | — | ✓ |
| SLA guarantee | — | — | — | ✓ |
ZIP Code API for US Address Lookups and Geolocation
A ZIP Code API enables developers to programmatically look up and validate United States ZIP codes, returning structured data such as city, state, county, latitude/longitude coordinates, and timezone. It is widely used for address validation at checkout, geolocation features, location-based filtering, and data enrichment in CRM and analytics systems.
What data does the ZipCodesToGo API return?
The ZipCodesToGo ZIP Code API covers all 42,000+ active US ZIP codes and returns the following fields per request: city name, state abbreviation, county name, latitude, longitude, and IANA timezone identifier. Higher-tier plans also include population data, radius search (find all ZIP codes within N miles), and bulk data export.
How to integrate the ZIP Code REST API
The API uses standard REST conventions. All requests are made via HTTPS GET, authenticated with an
API key passed in the X-Api-Key header. Responses are returned in JSON format, making it
straightforward to integrate with any language or framework — including
JavaScript,
Python,
PHP, Ruby,
and Go. A full endpoint reference is available in the API documentation.
Free ZIP Code API tier
The free plan provides 100 API calls per day and includes ZIP code lookup, city/state data, and latitude/longitude — no credit card required. It is suitable for development, testing, and low-volume production use. Upgrade to a paid plan for higher call volumes, radius search, and timezone data. See the free tier guide for a full comparison of what's included.
Why choose this ZIP Code API?
Unlike generic data providers, this API is focused specifically on US ZIP code lookups, resulting in faster response times, simpler endpoints, and predictable pricing. There are no per-field charges or complex query syntax — every lookup returns a consistent JSON object, making integration straightforward.
ZIP Code API vs. ZIP code database download
The API is the right choice for applications that need real-time, on-demand lookups — such as form validation, live delivery calculators, or dynamic location features. If you need the full dataset for offline processing, data pipelines, or bulk analysis, consider the ZIP code database download (available in CSV, Excel, and Access formats as a one-time purchase).
Learn more about ZIP code databases, using the API in JavaScript, Python integration examples, PHP integration examples, or what the free ZIP code API includes.