Every bounce costs you twice. Once because the message did not arrive, and again because mailbox providers count bounces against your domain and start routing your good email to spam. A bounce rate above two or three percent is enough to hurt deliverability for every campaign you send afterwards. The free Email Validator checks an address against six tests in a few seconds. This guide explains what each test means and how to act on the result.
Step 1: Paste the address and run the check
Enter the email address, add your own name and email so the result can be delivered, and the validator returns a verdict with the individual checks underneath it. There is no signup and no limit on how many addresses you check one at a time.
The six checks, in the order they run
Syntax validation
Is the address shaped like an email address? This catches typos, missing @ signs, spaces and illegal characters. A syntax failure is a hard no; the address cannot exist.
MX record lookup
Does the domain have mail servers? The validator looks up the domain’s MX records in DNS. A domain with no MX records cannot receive mail, which is common with typo domains (gmial.com) and with company domains that were registered but never set up for email.
SMTP mailbox verification
Does this specific mailbox exist? The validator connects to the domain’s mail server and asks whether it would accept mail for that address, without sending anything. This is the check that separates real validators from format checkers, and it is the one that catches the ex-employee whose address was deleted.
Disposable domain detection
Is this a temporary inbox? Services like Mailinator and 10minutemail create addresses that work for an hour and then vanish. People use them to get past a signup gate. A disposable address is deliverable today and gone tomorrow, so treat it as invalid for anything you plan to send later.
Role-based address detection
Is this a shared inbox? Addresses like info@, sales@, admin@ and support@ belong to a function rather than a person. They are usually valid, but they are read by whoever is on rota, and they complain more. Send to them only when the message is genuinely for the business rather than for an individual.
Catch-all identification
Will the server accept anything? Some domains are configured to accept mail for every address, whether or not the mailbox exists. The validator cannot prove a catch-all address is real, only that it will not bounce. Mark it as risky and decide based on how you obtained it.
Step 2: Read the verdict
Valid means it passed every check. Invalid means syntax, MX or SMTP failed and you should not send. Risky means it is deliverable but either disposable, role-based or behind a catch-all. The right response to risky depends on the source: a catch-all address from a signed contract is fine, a catch-all address from a scraped list is a coin flip.
Step 3: Validate at the right moments
There are three points where a quick check saves the most. When a lead fills in a form, so you can ask them to fix a typo while they are still on the page. Before a new list goes into a sequence, so bounces never happen. And before you re-engage an old list, because the older the data the more mailboxes have been deleted. If your old list is large, that is exactly the situation the AI Reactivation Setter ROI Calculator models: what the database is worth once it has been cleaned and worked.
Step 4: Fix the message too
A valid address only gets you to the mail server. Whether the message lands in the inbox depends on the content. Run the draft through the Cold Email Spam Checker to catch the trigger words, the link shorteners and the formatting that filters punish. Clean list plus clean copy is the whole deliverability game.
Bulk validation
The free tool checks one address at a time, which is right for the form on your website and for the handful of addresses you look up by hand. For lists in the thousands, we run bulk validation as part of our cold outbound campaigns, where every address is verified before the first send.
Privacy
The validator processes the address in real time and does not sell or share anything you submit. Your own contact details are used only to deliver the result and to follow up if you ask us to.
Check an address now. It takes a few seconds and could save your next campaign.
