Church Calendar vs MailCheck.ai

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

Uptime · 30d
Uptime · 90d100%93.1%
Uptime · 30d100%93.3%
P50 · ms848272
P95 · ms1997842
Authnonenone
CORSyesyes
HTTPSnoyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree — limits not published
Rate limitUnpublished5 req/window · 4 remaining
In directory since2026-07-052026-07-05
operationalpartialdownno data

Church Calendar vs MailCheck.ai: common questions

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

On our scheduled checks, Church Calendar leads on measured uptime — Church Calendar at 100% versus MailCheck.ai at 93.1% 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, Church Calendar or MailCheck.ai?

MailCheck.ai has the lower median latency in our checks — Church Calendar responds in 848 ms versus MailCheck.ai at 272 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 Church Calendar and MailCheck.ai need an API key?

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

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

Only MailCheck.ai is browser-friendly — it returns CORS headers over HTTPS. Church Calendar needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are Church Calendar and MailCheck.ai free for commercial use?

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