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.
Real SMTP checks where the provider allows them. Where they don't (for example Microsoft 365 and Yahoo), the address is marked PROTECTED instead of guessed.
Confirms the domain is configured to receive mail, and how reliably.
Flags domains that accept everything — the addresses most likely to silently bounce.
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