mail.tm vs The Calendar

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified (US federal list per 5 U.S.C. § 6103)
Free tierFree — temporary mailboxesFree, no auth (per site)
Rate limitRate limited (429 on exceed); exact policy per docs.mail.tmNone stated (site advertises no rate limit)
In directory since2026-07-052026-07-05
operationalpartialdownno data

mail.tm vs The Calendar: common questions

Which is more reliable, mail.tm or The Calendar?

On our scheduled checks, The Calendar leads on measured uptime — mail.tm at —% versus The 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 mail.tm and The Calendar need an API key?

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

Can I call mail.tm and The Calendar from the browser?

Yes — both mail.tm and The 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 mail.tm and The Calendar free for commercial use?

mail.tm has unclear commercial terms, and The 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.