Email Verification Results Guide

Every result we return falls into one of six statuses. Here's exactly what each one means, and what you should (and shouldn't) do with it.

VALID

The receiving mail server directly confirmed this mailbox exists, and we ruled out the domain being a catch-all. This is the strongest result we give.

What to do: Safe to send to, as far as verification can tell you. No verification can guarantee future delivery — mailboxes get deleted, full, or blocked after the fact.

VALID (ESTIMATED)

The domain and mail routing are solid, and multiple other independent signals (like a recognized mail provider) line up — but the mail server didn't give us a direct yes/no on the specific mailbox. This usually happens with providers like Gmail, Outlook, and Yahoo, which intentionally limit this kind of check.

What to do: Treat this as a well-supported estimate, not a confirmation. Fine for most everyday use; for a high-stakes send, you may want extra caution.

ACCEPT-ALL

This domain accepts mail sent to any address at all — real or made up — so it's technically impossible to confirm one specific mailbox from outside.

What to do: Common on business domains with certain mail server configurations. Not a red flag by itself, just a limit on what verification can tell you here.

UNKNOWN

We genuinely don't have enough evidence to say either way — the mail server didn't respond usefully, and no other signal filled the gap.

What to do: Use your judgment. If the address came from a trusted source (like someone typing their own email into a form), it's probably fine. If it came from a purchased or scraped list, treat it with more caution.

INVALID

Either the domain doesn't exist, there's no mail routing set up for it at all, or the mail server explicitly and permanently rejected the mailbox.

What to do: Remove these from your list. Sending to INVALID addresses is one of the fastest ways to damage your sender reputation.

DISPOSABLE

This domain is a known temporary/throwaway email provider, used for one-time signups rather than real ongoing communication.

What to do: Depends on your use case. For a newsletter or CRM, these are usually low-value and safe to remove.

An important honesty note

Email verification is not a guarantee of future delivery. Mail servers can change behavior, catch-all systems can hide mailbox status, and some providers block verification outright. No tool — free or paid — can promise 100% accuracy, and you should be skeptical of any that claims otherwise.

Try the free verifier or read how email verification works for the technical detail behind these results.