Real MX record checks, typo correction, disposable and role detection, and duplicate collapsing — all in your browser. Your list is never uploaded, stored, or sent to a verification company.
Or drag a file onto the box — choose a CSV or text file.
| Address | Result | Why | Suggestion |
|---|
It checks: address syntax against the actual rules rather than a rough pattern; whether the domain has MX records and can therefore receive mail at all; likely typos in the domain; disposable and throwaway providers; role addresses like info@ and sales@; free-provider versus business domains; duplicates, including the ones most tools miss; and lookalike characters used to disguise a domain.
It can't confirm that a specific mailbox exists. That requires an SMTP conversation on port 25, which no browser can open. Any tool claiming a full mailbox check is doing it on a server, and charging you per address for it.
So this is a cleaner, not a verifier. It removes the addresses that are provably bad before you spend money on the rest — which on a typical scraped or aged list is a meaningful share of it.
Every paid verification service requires you to upload your customer list to their servers. For most people that's the real cost, not the per-address price. Here the checks run on your own device. MX lookups go to Cloudflare's public DNS resolver, which sees the domain being asked about — never the addresses, never your list.
Turn off "Check MX records" and nothing leaves your device at all.
Valid — correct syntax, the domain accepts mail, nothing suspicious. Invalid — malformed, or the domain cannot receive mail. Risky — deliverable but worth thinking about: role addresses, disposable providers, suspected typos. Unknown — the DNS lookup didn't complete, so nothing is claimed either way.
It removes the addresses that are provably bad before you spend money verifying or sending to the rest — malformed addresses, domains that can't receive mail at all, disposable providers, role addresses and duplicates.
No, and neither can anything else running in a browser. Confirming a specific mailbox requires an SMTP conversation on port 25, which browsers cannot open. Any tool claiming a full mailbox check is doing it on a server and charging per address.
Valid means correct syntax with a domain that accepts mail and nothing suspicious. Invalid means malformed, or the domain cannot receive mail. Risky means deliverable but worth a thought — role addresses, disposable providers, suspected typos. Unknown means a DNS lookup didn't complete, so nothing is claimed either way.
Validation checks that an address is correctly formed and that its domain can receive mail. Verification goes further and confirms the specific mailbox exists. This tool does the first thoroughly and is honest that it cannot do the second.
No. The checks run on your device. MX lookups go to Cloudflare's public DNS resolver, which sees only the domain being asked about — never your addresses and never your list. Turn off the MX check and nothing leaves your device at all.
It only suggests a correction when a domain is very close to a common provider, the same length give or take a character, and starts with the same letter. Legitimate domains like acme.com and nike.com are deliberately left alone. Flagged results are marked risky, never invalid.