Most tools return valid/invalid. VerifyFlow gives you SAFE, PROTECTED, RISKY, or DEAD — a clear action for every address on your list.
Verify FreeEvery address resolves to one of four buckets — each with a clear next step.
Send freely
Sendable with care
Avoid
Remove immediately
A score of 67 tells you nothing. PROTECTED tells you exactly what to do.
Is that good? Send it or not? You're left to guess — and guessing burns your domain reputation.
An instruction, not a riddle. Every bucket maps to a decision you can act on immediately — no interpretation required.
No single check is enough. We combine real network signals into one verdict.
A live conversation with the mail server — not just a syntax or regex check.
Confirms the domain is configured to receive mail, and how reliably.
Flags domains that accept everything — the addresses most likely to silently bounce.
Cross-references the sending domain against major spam blocklists.
Weighs whether the mailbox pattern looks real or machine-generated.
Older, established domains behave differently from freshly registered ones.
Catch-all servers return 250 OK to everything. Most tools mark the entire domain as unknown. VerifyFlow resolves catch-all addresses to a concrete bucket — not a shrug.
# a catch-all accepts every recipient you throw at it > MAIL FROM:<probe@verifyflow.io> 250 OK > RCPT TO:<definitely-not-real-9f3a2@catch-all-domain.com> 250 Accepted ← accepts a fake address > RCPT TO:<ceo@catch-all-domain.com> 250 Accepted ← identical answer — the probe alone proves nothing
Other tools stop at that ambiguous 250 and give up. VerifyFlow weighs the probe alongside its other signals to place each address in a real bucket — so a catch-all domain becomes an actionable list, not a dead end.
Score your list SAFE, PROTECTED, RISKY, or DEAD and know exactly what to send — and what to cut.
Verify Free