Check any email address in seconds
Paste an address, get a verdict. MailTester opens a live connection to the receiving mail server and tells you — with evidence — whether the mailbox exists, before you ever hit send.
Enter any address to run a real verification — syntax, MX, mailbox and disposable checks.
One bad address costs more than you think
An email address is a claim, not a fact. People mistype them, abandon them, and invent them to get past your forms — and every one that slips through costs you on the next send.
Typos look like real addresses
[email protected] passes every syntax check ever written. It will also bounce, count against your sender reputation, and lose you the contact who actually wanted to hear from you.
Dead mailboxes don't announce themselves
People change jobs and abandon inboxes constantly. The address that was valid when you collected it may be a hard bounce today — and you find out only after you've sent.
Bounces compound silently
Gmail and Outlook track your bounce rate. Cross 2% and your campaigns start landing in spam for everyone — including the subscribers who open every email.
A real SMTP conversation, not a database lookup
Most checkers consult cached lists and pattern rules, then guess. MailTester connects to the actual receiving mail server for every check and asks it directly whether the mailbox exists. The server's own answer is the verdict — and we hang up before any message is sent, so the owner never knows.
- Live MX resolution and SMTP handshake on every single check
- No message is ever delivered — the conversation stops at the mailbox check
- Greylisted servers are retried automatically with correct timing
A 0–100 score, because valid isn't the whole story
A mailbox can exist and still be a bad bet: a role account that complains, a free inbox that churns, a catch-all domain that accepts everything. Every check returns a quality score built from a dozen signals, so you can set your own bar instead of trusting a binary verdict.
- Mailbox status, domain health, disposable and role signals in one number
- Catch-all domains flagged honestly as risky — never guessed as valid
- Full evidence trail: every individual check and its result
Typos corrected while the user is still there
Around one in twenty form fills contains a domain typo. MailTester recognizes the common slips — gmial.com, hotmial.com, yaho.com and hundreds more — and suggests the correction instantly. One click turns a guaranteed bounce into a real, reachable contact.
- Did-you-mean suggestions for hundreds of common domain typos
- Re-check the corrected address with a single click
- Every check saved to your dashboard history for reference
Enter any address to run a real verification — syntax, MX, mailbox and disposable checks.
Three steps, no learning curve
- 01
Paste any address
Type or paste the email you want to check — one field, no setup, no list required.
- 02
We interrogate the mail server
Syntax, MX records, live SMTP handshake, disposable and role detection — all in a couple of seconds.
- 03
Act on the verdict
Deliverable, risky, or undeliverable — with the full evidence trail and a score, saved to your dashboard history.
- 99%
- verification accuracy
- ~2s
- typical time to verdict
- 0
- emails sent to the address
- 100
- free checks on signup
Everything a single check includes
Live SMTP check
We talk to the actual mail server — no cached verdicts, no pattern guessing, no stale databases.
Quality score
A 0–100 score combining mailbox status, domain health, disposable and role-account signals.
Typo correction
gmial.com becomes gmail.com before it bounces — with a one-click re-check of the suggestion.
Disposable detection
Temporary inboxes from thousands of disposable providers are flagged the moment you check them.
Anti-greylisting
Servers that say “try again later” get correctly timed retries — a definitive answer, not an “unknown”.
Role & free detection
info@, sales@ and free-provider addresses are identified so you can segment them appropriately.
Built into daily workflows
Sales teams
Qualify a prospect's address before the first cold email — no bounce, no burned domain.
Recruiters
Confirm a candidate's contact details are live before the offer letter goes out.
Support & success
Check a customer's address on file when messages start going unanswered.
Product teams
The same check is one API call — wire it into signup forms and block fakes at the door.
Efficient, reliable and pocket friendly — I love MailTester.com. I have personally recommended this app to my entrepreneur friends.
I am a fan. MailTester.com is super accurate and easy to use. I set it up and forget about it.
What happens during a single email verification?
A proper verification is a sequence of escalating checks. First, syntax: is the address even structurally valid? Then DNS: does the domain exist, and does it publish MX records — the servers that agree to receive its mail? Then the expensive part: an SMTP conversation with that server, in which we introduce ourselves exactly like a sending mail server would and ask whether the specific mailbox accepts mail. We disconnect before any message is transmitted.
Alongside the live conversation, the address is screened against databases of disposable providers, role-account patterns and free-mail domains, plus a typo dictionary covering hundreds of common misspellings. The combined result is a verdict — ok, risky or fail — a 0–100 quality score, and the reason behind it.
When is a single check the right tool?
Single verification is for moments, not lists: the prospect you're about to cold-email, the customer record that started bouncing, the address a colleague scribbled on a note. It's also the fastest way to evaluate MailTester itself — paste an address you know, and watch what the engine reports.
If you're holding a file with hundreds or thousands of rows, use bulk list verification instead: same engine, same accuracy, with deduplication and segmented downloads on top. And if you want checks to happen automatically at signup, the API runs this exact verification in about a second per call.
Pay only for what you verify
Credits from $19, volume rates down to $0.0003 per email — and they never expire. Subscriptions bundle inbox testing and monitoring.
How many emails do you need to verify?
50,000credits
$79
$0.0016 per email
Common questions
Your first 100 checks are free.
No credit card, no sales call. Paste an address and see the engine work.