shipapis
StarSubmit an APISubmit API

PostalCodes vs Zipcodestack

Same instrument, two spec sheets — measured, not claimed.

APIPostalCodesNEW—ZipcodestackNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
AuthnoneapiKey
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree tier — API key required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

PostalCodes vs Zipcodestack: common questions

Which is more reliable, PostalCodes or Zipcodestack?

On our scheduled checks, Zipcodestack leads on measured uptime — PostalCodes at —% versus Zipcodestack at —% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Do PostalCodes and Zipcodestack need an API key?

PostalCodes needs no key, while Zipcodestack requires a free API key. If you want to start calling without signup, reach for PostalCodes first.

Can I call PostalCodes and Zipcodestack from the browser?

Only Zipcodestack is browser-friendly — it returns CORS headers over HTTPS. PostalCodes needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are PostalCodes and Zipcodestack free for commercial use?

PostalCodes has unclear commercial terms, and Zipcodestack has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.