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APIs.guru vs MailboxValidator Free Email Checker

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

APIAPIs.guruHEALTHY97MailboxValidator Free Email CheckerHEALTHY94
Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms266527
P95 · ms14211138
AuthnoneapiKey
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree and open, no keyFree tier — API key required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

APIs.guru vs MailboxValidator Free Email Checker: common questions

Which is more reliable, APIs.guru or MailboxValidator Free Email Checker?

Both are neck-and-neck — APIs.guru and MailboxValidator Free Email Checker each measure 100% uptime over 90 days on our probe schedule. Reliability here is verified from our own scheduled checks; use the 30-day bars above to see which has been steadier lately.

Which is faster, APIs.guru or MailboxValidator Free Email Checker?

APIs.guru has the lower median latency in our checks — APIs.guru responds in 266 ms versus MailboxValidator Free Email Checker at 527 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 APIs.guru and MailboxValidator Free Email Checker need an API key?

APIs.guru needs no key, while MailboxValidator Free Email Checker requires a free API key. If you want to start calling without signup, reach for APIs.guru first.

Can I call APIs.guru and MailboxValidator Free Email Checker from the browser?

Only APIs.guru is browser-friendly — it returns CORS headers over HTTPS. MailboxValidator Free Email Checker needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are APIs.guru and MailboxValidator Free Email Checker free for commercial use?

APIs.guru has unclear commercial terms, and MailboxValidator Free Email Checker 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.