MailboxValidator Free Email Checker vs VATlayer

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
AuthapiKeyapiKey
CORSnono
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree tier — API key requiredFree tier — key may be required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

MailboxValidator Free Email Checker vs VATlayer: common questions

Which is more reliable, MailboxValidator Free Email Checker or VATlayer?

On our scheduled checks, VATlayer leads on measured uptime — MailboxValidator Free Email Checker at —% versus VATlayer 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 MailboxValidator Free Email Checker and VATlayer need an API key?

Both ask you to authenticate — MailboxValidator Free Email Checker uses an API key and VATlayer uses an API key. Each key is free to obtain; the Auth and Card-required rows above spell out the signup terms.

Can I call MailboxValidator Free Email Checker and VATlayer from the browser?

Neither sends browser-friendly CORS headers reliably, so call MailboxValidator Free Email Checker and VATlayer from a server or proxy rather than client-side. The CORS and HTTPS rows above show exactly what we detected for each.

Are MailboxValidator Free Email Checker and VATlayer free for commercial use?

MailboxValidator Free Email Checker has unclear commercial terms, and VATlayer 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.