IPWhois vs PostalCodes
Same instrument, two spec sheets — measured, not claimed.
IPWhois vs PostalCodes: common questions
Which is more reliable, IPWhois or PostalCodes?
On our scheduled checks, IPWhois leads on measured uptime — IPWhois at 100% versus PostalCodes at 99.02% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.
Which is faster, IPWhois or PostalCodes?
IPWhois has the lower median latency in our checks — IPWhois responds in 23 ms versus PostalCodes at 1030 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.
Do IPWhois and PostalCodes need an API key?
PostalCodes needs no key, while IPWhois requires a free API key. If you want to start calling without signup, reach for PostalCodes first.
Can I call IPWhois and PostalCodes from the browser?
Neither sends browser-friendly CORS headers reliably, so call IPWhois and PostalCodes from a server or proxy rather than client-side. The CORS and HTTPS rows above show exactly what we detected for each.
Are IPWhois and PostalCodes free for commercial use?
IPWhois 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.