Free tool · no sign-up

Free email address validator

Type an address and get a full verification report in seconds: syntax, provider rules, DNS and mail server, a real SMTP mailbox check, disposable/role detection and a plain-language explanation of the verdict. 10 checks per day, free.

Free checks today: 10

How this e-mail validator works

  1. 1

    Syntax & provider rules

    RFC 5322 parsing, invalid characters, TLD, internationalized domains — plus the providers' own username rules (a 3-letter Gmail username cannot exist).

  2. 2

    DNS & mail server

    MX, A, SPF, DMARC and DKIM records; Null MX; parked or for-sale domains; the mail provider behind the domain.

  3. 3

    Real mailbox check

    An SMTP conversation with the mail server asks whether the mailbox exists — without sending any message. Full mailboxes, greylisting and catch-all servers are recognised.

  4. 4

    Risk & explanation

    Disposable, role-based, no-reply and toxic patterns, typo suggestions, a 0–100 score with grade and confidence — and a status code you can read.

Why validate an e-mail address before using it?

10–15% of a typical list is invalid and it decays about 2% a month. Every bounce hurts your sender reputation; above ~2% bounce, providers start filtering you. Validating one address here — or a whole list, an API call or a form in real time with an account — keeps that from happening.

→ A free account gives you 200 credits (10 for free-provider e-mails): bulk lists with a Quality Report, the REST API and the real-time widget for your forms.

Status codes explained

Every result carries one of these codes. They are the same codes returned by the AT Valid API and shown in bulk reports.

Success Success
The mailbox exists and accepted our probe. The address is deliverable.
MailboxDoesNotExist Mailbox does not exist
The mail server told us there is no such user. Sending will bounce.
MailboxHasInsufficientStorage Mailbox full
The account exists but is over quota — messages bounce until the owner frees space.
ServerIsCatchAll Server is catch-all
The domain accepts any address, so the server cannot confirm this specific mailbox. We add an evidence score (0–10) from other signals.
DomainDoesNotExist Domain has no mail server
No MX and no A record could be resolved for the domain — nothing can receive mail there.
DomainHasNullMx Domain refuses e-mail (Null MX)
The domain publishes "MX 0 ." (RFC 7505): it explicitly declares that it does not accept e-mail.
DomainIsMisspelled Domain looks misspelled
The domain is one or two characters away from a popular provider (gmial.com → gmail.com). We suggest the correction.
DisposableAddress Disposable address
The domain belongs to a temporary-mail service. The mailbox will vanish in minutes or hours.
RoleAddress Role-based address
info@, sales@, support@… shared inboxes read by several people; fine for transactional mail, poor for marketing.
ToxicAddress Toxic address
Sending here damages your reputation: spam-trap patterns, blacklisted or parked domains, no-reply. Never send.
InvalidSyntax Invalid e-mail format
The address does not follow the RFC 5322 structure (local part, @, domain with a valid TLD).
InvalidCharacterInSequence Invalid character in sequence
A character that cannot appear in an e-mail address (space, comma, quote…) was found. We show its position.
IspSpecificSyntaxFailure Fails the provider's own rules
The format is RFC-valid, but the provider would never issue this username (e.g. Gmail requires 6–30 characters, letters/digits/dots only).
MailboxTemporarilyUnavailable Temporarily unavailable (greylisting)
The server asked us to try again later. In bulk jobs we re-check automatically; try again in a few minutes.
ProbeRejected Server rejected the probe
The mail server refused to talk to our verifier (policy, blocklist or relay rules). The mailbox status could not be confirmed.
DomainIsParked Domain is parked
The domain shows a parking / for-sale page and has no real mail service behind it.
NoReplyAddress No-reply address
An automated sender address that is not read by anyone.
Unknown Unknown
Not enough signals to classify the address with confidence.

Frequently asked questions

Is this e-mail validator really free?

Yes — 10 checks per day per visitor, no sign-up. A free account adds 200 credits for bulk lists, the API and the form widget.

Does it send an e-mail to the address?

No. We open an SMTP conversation with the mail server to ask whether the mailbox exists and close it before any message is sent. The owner never notices.

Why is a Gmail address with a short name "undeliverable"?

Gmail usernames are 6–30 characters of letters, digits and dots. An address like [email protected] is RFC-valid but cannot exist — we flag it as IspSpecificSyntaxFailure without even contacting Google.

What does "catch-all" mean?

The domain's server accepts any address, so it cannot confirm a specific mailbox. We add an evidence score (0–10) from other signals — a real-looking name, corporate mail gateway, domain maturity — so you can decide.

Can I validate a whole list?

Yes: create a free account, upload a CSV/Excel and get a per-address report plus a List Quality Report with projected bounce rate. Recurring monitors keep the list clean automatically.

Is my data stored?

The address is used only for this validation; the report is cached for one hour so repeated checks don't re-probe the server. Addresses are never sold or reused.

Need more than 10 a day?

A free account gives you 200 credits (10 for free-provider e-mails): bulk lists with a Quality Report, the REST API and the real-time widget for your forms.

Create free account — 200 credits

No credit card. Credits never expire.