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MailCheck.ai vs Namedays Calendar

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

APIMailCheck.aiNEW—Namedays CalendarNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree — limits not published
Rate limit5 req/window · 4 remainingUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

MailCheck.ai vs Namedays Calendar: common questions

Which is more reliable, MailCheck.ai or Namedays Calendar?

On our scheduled checks, Namedays Calendar leads on measured uptime — MailCheck.ai at —% versus Namedays Calendar 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 MailCheck.ai and Namedays Calendar need an API key?

Neither needs a paid key — MailCheck.ai is callable with no signup, and Namedays Calendar is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call MailCheck.ai and Namedays Calendar from the browser?

Yes — both MailCheck.ai and Namedays Calendar 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 MailCheck.ai and Namedays Calendar free for commercial use?

MailCheck.ai has unclear commercial terms, and Namedays Calendar 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.