OkSurf vs WhoisXML API Email Verification API

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

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

OkSurf vs WhoisXML API Email Verification API: common questions

Which is more reliable, OkSurf or WhoisXML API Email Verification API?

On our scheduled checks, WhoisXML API Email Verification API leads on measured uptime — OkSurf at —% versus WhoisXML API Email Verification API 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 OkSurf and WhoisXML API Email Verification API need an API key?

OkSurf needs no key, while WhoisXML API Email Verification API requires a free API key. If you want to start calling without signup, reach for OkSurf first.

Can I call OkSurf and WhoisXML API Email Verification API from the browser?

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

Are OkSurf and WhoisXML API Email Verification API free for commercial use?

OkSurf has unclear commercial terms, and WhoisXML API Email Verification API 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.