USPS v3 developer toolkit

The USPS API you wish existed.

Address validation, rate quotes, labels, and tracking. Free tier for validation and rates. Flat monthly pricing when you need labels, tracking, and BYOK.

Try it — no signup needed

Free tier covers address validation, address extract, city/state lookup, domestic and international rates, service standards, shipping options, and locations — no signup needed.

Capabilities

Address Validation DPV confirmation, ZIP+4, business/residential

Rate Quotes Domestic + international, all mail classes

Label Creation PDF and ZPL output, void support

Package Tracking Normalized USPS tracking updates

Pickup Scheduling Schedule USPS pickups for prepaid parcels

Service Standards Transit times by origin/destination/class

Free Tools — No Signup Required

Rate Calculator Compare every USPS service option. Enter weight + ZIP codes, get instant rate quotes.

AI Box Sizer Describe your item. AI picks the optimal USPS box and shows the cheapest way to ship it.

Address Validator Check any US address with USPS DPV confirmation, ZIP+4 enrichment, and standardized formatting.

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188 tests · USPS v3 REST · Free tier live