Free disposable email checker

How to read the verdict

The headline is the short answer: Reject this address, Probably a mistake or Looks deliverable. Below it are the reasons, the DNS result and the domain's mail servers. Here is what each reason means, and what Vetto does with it on a signup form by default:

What this checker looks at

It runs the same engine that guards Vetto signup forms, minus the signals that need a real visitor, such as their network or their earlier accounts.

Known throwaway domains

The domain, and each of its parent domains, is matched against 9,222 throwaway domains from the public-domain disposable-email-domains project. Parents matter: abc.mailinator.com is as disposable as mailinator.com, and Clerk checks parent domains the same way. You can search and download the full disposable domains list.

To be plain about coverage: 9,222 domains is a smaller list than some vendors advertise. Hunter says it checks more than 180,000 known throwaway domains. If raw list size is what you are buying, compare first; our honest IsItDisposable comparison goes through the trade-offs.

Learned throwaway mail servers

Throwaway services register new domains all the time but tend to reuse their mail servers. When several known throwaway domains share a mail server, Vetto treats that server as throwaway infrastructure and flags new domains that point at it, even before they appear on any list. Big shared providers such as Google, Microsoft and Zoho are excluded, so a company on Google Workspace is never caught by this rule.

Dead domains

A live DNS lookup decides whether the domain can receive mail at all:

• NXDOMAIN: the domain does not exist.
• Null MX: the domain publishes the 0 . record from RFC 7505, which says it accepts no mail.
• No MX, A or AAAA record: there is nowhere to deliver a message.

A domain with no MX record but with an address record is not dead. RFC 5321 tells senders to treat the domain itself as an implicit mail server in that case, so the checker reports that mail may still be delivered instead of rejecting the address.

Typos and lookalikes

jane@gmial.com is a real person who mistyped, so the checker suggests jane@gmail.com instead of rejecting them. Lookalikes are the nastier case: gmai.com runs a live mail server, so an MX-only check passes it, and your welcome email would reach whoever operates that server. The email typo checker covers the common misspellings in more depth.

Relays, free mail and role accounts

These are tags, not problems: a privacy relay (more below), a consumer mailbox such as Gmail, or a shared inbox such as info@. Most products should accept all three.

A single address cannot reveal an alias farm: j.a.n.e+trial7@googlemail.com only looks suspicious next to jane@gmail.com. To see whether two addresses reach the same inbox, use the Gmail alias checker.

Disposable vs privacy relay: why Apple Hide My Email is allowed

Both hide the user's real address, but they signal opposite things. A 10-minute inbox exists so the person can disappear once they have what they came for. A relay such as Apple Hide My Email (privaterelay.appleid.com), Firefox Relay, addy.io or SimpleLogin forwards to the person's real inbox for as long as they keep it.

DeBounce's guide to blocking disposable email draws the same line: relay users can stay engaged for months or years, while classic throwaway addresses almost never engage. It recommends allowing relays by default and hard-blocking throwaways. Vetto does exactly that: relays pass with a relay tag that shows up in your stats. On Pro you can change the relay policy if they ever become a problem.

"Not disposable" doesn't mean "deliverable"

A clean result means the domain is not a known throwaway and can receive mail. It does not prove that the mailbox exists on that domain. Hunter makes the same point on its own disposable checker.

Vetto reads public DNS only. It never connects to mail servers to test inboxes: that is slow, can get the checking server greylisted or blocklisted, and gives no clear answer on catch-all domains that accept every address. For signup forms that trade-off is deliberate:

• At signup: block throwaway and dead domains, fix typos, then send a confirmation email. If nobody clicks it, the mailbox did not exist or nobody cared.
• Before a bulk send to an old list: use an SMTP verification service. That is a different job; the Kickbox comparison explains when each tool fits.

How common are throwaways? In BounceZero's 2026 dataset of 7.8 million addresses (vendor data from November 2025 to June 2026, drawn from outreach lists, B2B prospecting exports, CRM clean-ups and newsletter signups), 6.9% were classified as disposable. Free-trial signup forms can see more or less than that. The free email list audit gives you your own number.

Block disposable emails on your own form

Checking one address by hand is handy for support tickets. For signups, run it automatically: the Vetto script checks each email field when the visitor leaves it and shows the result under the field.

<script src="https://usevetto.com/v.js" data-site="pk_your_public_key" defer></script>

• Free: typo rescue, throwaway and dead-domain blocking, relay tagging and a honeypot that catches simple bots, on 1 site with 1,000 checks a month.
• Pro ($12/month or $99/year): lookalike domains, alias and repeat-signup detection, datacenter/VPN/Tor and burst signals, a deny list, a signed token your server can verify, alerts and a 90-day log. On Free, these signals run in shadow mode: counted in your stats, never shown to visitors.
• If Vetto does not answer within 800 ms, the form submits as if it were not installed.

A check that only runs in the browser can be skipped by a bot posting straight to your API, so enforce the verdict on your server too. The guide to blocking disposable emails on any signup form covers the common stacks and server-side enforcement. If the real problem is people farming free trials, the free trial abuse playbook covers the other layers.