IP Address API vs PostalCodes

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
Authnonenone
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree — limits not published
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

IP Address API vs PostalCodes: common questions

Which is more reliable, IP Address API or PostalCodes?

On our scheduled checks, PostalCodes leads on measured uptime — IP Address API at —% versus PostalCodes 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 IP Address API and PostalCodes need an API key?

Neither needs a paid key — IP Address API is callable with no signup, and PostalCodes is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call IP Address API and PostalCodes from the browser?

Only IP Address API 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 IP Address API and PostalCodes free for commercial use?

IP Address API has unclear commercial terms, and PostalCodes 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.