Chronicling America 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 useyesunclear
Data licensePublic domain / no known copyright (Library of Congress)Unverified
Free tierFree — public-domain collection dataFree tier — API key required
Rate limitLoC throttles heavy crawling (see LoC API policy)Unpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Chronicling America vs WhoisXML API Email Verification API: common questions

Which is more reliable, Chronicling America or WhoisXML API Email Verification API?

On our scheduled checks, WhoisXML API Email Verification API leads on measured uptime — Chronicling America 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 Chronicling America and WhoisXML API Email Verification API need an API key?

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

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

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

Are Chronicling America and WhoisXML API Email Verification API free for commercial use?

Chronicling America allows commercial use on its free tier, 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.