CountryStateCity vs US ZipCode
Same instrument, two spec sheets — measured, not claimed.
CountryStateCity vs US ZipCode: common questions
Which is more reliable, CountryStateCity or US ZipCode?
On our scheduled checks, US ZipCode leads on measured uptime — CountryStateCity at —% versus US ZipCode 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 CountryStateCity and US ZipCode need an API key?
Both ask you to authenticate — CountryStateCity uses an API key and US ZipCode uses an API key. Each key is free to obtain; the Auth and Card-required rows above spell out the signup terms.
Can I call CountryStateCity and US ZipCode from the browser?
Yes — both CountryStateCity and US ZipCode send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.
Are CountryStateCity and US ZipCode free for commercial use?
CountryStateCity has unclear commercial terms, and US ZipCode 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.