Free ZIP Code API — What's Included, What's Not
Understand rate limits, data fields, and reliability before you build. Then decide whether the free tier fits your project — or when you need production-grade access.
ZipCodesToGo Free Tier
The free plan is a real, production API key — not a demo or sandbox. It connects to the same infrastructure as paid plans. The only difference is the daily call limit and available endpoints.
- ✓ZIP code lookupAll 42,000+ US ZIPs
- ✓City & stateFull name + 2-letter abbreviation
- ✓CountyCounty name (no "County" suffix)
- ✓Latitude & longitudeDecimal degrees
- ✓City searchLook up ZIPs by city + state
- ✓Commercial useAllowed on all plans
- —Timezone / DST dataPro & Enterprise only
- —Radius searchBasic+ plans
- —Population dataPro & Enterprise only
- —Uptime SLAEnterprise only
Daily limit: 100 calls/day, resetting at midnight UTC. No credit card required — just an email address to receive your key.
✓ Free tier is enough if you…
- Are building a prototype or side project
- Need fewer than 100 lookups per day
- Only need city, state, county, and lat/lng
- Are validating ZIP codes in a low-traffic form
- Are evaluating the API before committing
- Need commercial use rights without a subscription
✗ You need a paid plan if you…
- Expect more than 100 API calls per day
- Need timezone or DST data
- Need radius search (find ZIPs within N miles)
- Need population data for marketing or analytics
- Need an uptime SLA for production apps
- Need bulk data export or database access
| Feature | Free | Basic $19/mo | Pro $39/mo | Enterprise $89/mo |
|---|---|---|---|---|
| Daily calls | 100 | 5,000 | 50,000 | Unlimited |
| ZIP code lookup | ✓ | ✓ | ✓ | ✓ |
| City, state, county | ✓ | ✓ | ✓ | ✓ |
| Lat / lng | ✓ | ✓ | ✓ | ✓ |
| City search | ✓ | ✓ | ✓ | ✓ |
| Radius search | — | ✓ | ✓ | ✓ |
| Timezone data | — | — | ✓ | ✓ |
| Population data | — | — | ✓ | ✓ |
| Bulk export | — | — | — | ✓ |
| Uptime SLA | — | — | — | ✓ |
| Credit card required | No | Yes | Yes | Yes |
Understanding Free Tier Limitations
When evaluating any free ZIP code API, there are a few things worth checking before you build on it — especially for production use.
Rate limits
Free tiers universally have rate limits. The question is whether the limit is per minute, per day, per month, or tied to a trial period that expires. The ZipCodesToGo free tier is 100 calls per day, permanent — not a trial. It does not expire.
Data freshness
ZIP codes change. The USPS adds, deactivates, and modifies ZIP codes periodically. Some free data sources rely on static datasets that haven't been updated in years. The ZipCodesToGo database is maintained and updated to reflect current USPS ZIP code data.
Missing fields
Many free ZIP code data sources return only city and state — leaving out county, lat/lng, or timezone. Before choosing an API, confirm it returns the specific fields your application needs. Even the ZipCodesToGo free tier includes city, state, county, latitude, and longitude. Timezone data requires a paid plan.
Reliability
Free public APIs sometimes have no uptime commitments. If your application depends on ZIP code lookups in a checkout flow or address form, an unreliable API creates a poor user experience. If uptime is critical, consider at minimum a Basic plan, or Enterprise for a formal SLA.
429 Too Many Requests response. Your limit resets at midnight UTC. You can upgrade to a paid plan at any time.