Questions, answered straight

99% — and we have been measuring it in production for over two decades. Every address gets a live SMTP check against the receiving mail server — we don't guess from cached data.

No. The SMTP conversation stops before any message is transmitted. The mailbox owner never sees anything.

The address exists but carries a quality concern: a catch-all domain, a disposable provider, or a role account like info@. We give it a 0–100 score so you can decide whether to send, segment, or drop.

Catch-all servers accept mail for any address, so no verifier can prove a specific mailbox exists. We flag them honestly as risky with a score — instead of guessing “valid” and letting you eat the bounce.

Some servers temporarily reject first-time connections to deter spammers. Tools that don't retry give up and bill you for an “unknown”. MailTester retries with correct timing and converts most of these into definitive answers.

Never. Pay-as-you-go credits stay on your account until used. Subscription allowances reset monthly.

Every new account includes 100 free verifications — no credit card required. Syntax-invalid addresses and duplicates are always filtered free and never consume credits.

All payments generate a downloadable invoice automatically. Business and Enterprise customers can pay by bank transfer on net-30 terms.

If accuracy lets you down, contact us within 30 days — we'll re-verify the list free or refund the credits in question.

They're encrypted in transit and at rest, used solely to produce your verification results, never shared or sold, and permanently deletable from your dashboard with one click.

Yes. Email addresses are processed as a data processor on your behalf, with a DPA available for all customers. Data is deleted on request or automatically per your retention settings.

Yes — team accounts share one credit pool with per-member activity visible to admins. Available on Growth plans and above.