Check email address online for syntax errors, domain health, MX records, and SMTP deliverability in under 2 seconds. You can check email address for free here — 99.9% accuracy, 600 credits a month, plus 20 more every day you log in.
Paste any address and get a full report. BillionVerify will check email address syntax, domain health, MX records, SMTP mailbox status, disposable providers, and role accounts — check email address for free, one result, one place to decide.
Six layers run automatically every time you check email address for free.
Check email address format and structure for typos, invalid characters, and malformed shapes.
Check that the domain exists and is configured to receive mail at all.
Check for active mail server records before spending a mailbox query on the domain.
Connect to the mail server and check that the mailbox itself accepts incoming mail.
Check the domain against 10,000+ known temporary email services.
Check for generic addresses like info@, support@, and admin@ that hurt engagement.
Four automated steps run every time you check email address input.
Check email address syntax and catch the typos and malformed shapes a human eye slides past.
Check that the domain resolves and publishes MX records, so the run knows delivery is possible before it goes further.
Connect to the mail server and check whether that specific mailbox accepts mail. This is the step a format checker cannot do.
Check the address for disposable, role, catch-all, and spam-trap risk alongside the verdict.
<2s
Response Time
Average SMTP verification
99.9%
Accuracy
Multi-layer validation
600
Free Monthly Credits
No signup required
6
Validation Layers
Per address checked
Each tool narrows the check to one specific risk type. Check email address for free on any of them.
Full SMTP verification with clear deliverability status.
Check free webmail providers (Gmail, Yahoo, Outlook, and more).
What “valid” means for format, domain, and mailbox checks.
How to tell if an address is real before you send.
Step-by-step guide with verification best practices.
What the check covers
A useful check email address result is built from layers that each answer a different question. Check them in order and the answer stays honest; skip one and the check starts overstating what it knows.
The check splits the local part before the @ from the domain after it, normalises case, and rejects shapes no mail system can use — missing domains, stray spaces pasted in from a spreadsheet, doubled dots, illegal characters. Every check email address run starts here.
This layer is instant and costs nothing against the recipient, which is why we check it first. It also catches the single most common problem people bring here: a plain typing mistake nobody noticed at the keyboard.
Next the check looks up the domain itself. A registered domain that resolves is the minimum precondition for everything after it; a lapsed or invented domain ends the check with a clear reason instead of a vague failure.
Domain problems are worth separating from mailbox problems. One means the whole company address is wrong; the other means this particular person is not there. A good check email address result names which one you are looking at.
Mail exchanger records tell every sender which server accepts mail for a domain, so the check reads them before it goes any further. No usable MX route means nothing will arrive, however well the address is written.
Plenty of real domains publish a website but never accept mail. Check email address online against MX records and you catch that class of failure before spending a mailbox query on it.
The decisive layer opens a real SMTP conversation with the receiving server and tests the recipient path. Check email address online here and no message is delivered, nothing lands in anyone's inbox, and no one is notified that you looked.
This is what separates a real check from a format screen. Everything before it describes the address; only this check describes the mailbox.
The check also flags temporary providers and shared functional inboxes such as info@, sales@, and support@. Both usually accept mail, and both are usually the wrong destination for a personal message, so we check for them separately.
These are attributes, not failures. Keeping them beside the verdict is what lets you check email address deliverability and address quality as two separate questions rather than one blurred score.
Reading the answer
Four outcomes, four different actions. Treating a check email address result as a yes/no is where most of the value gets thrown away.
The mailbox accepted the probe at the moment of the check. Send, subject to whatever consent and targeting rules your own system enforces — a check email address online result cannot evaluate those for you.
The answer carries a timestamp, not a guarantee. Check email address status again before a campaign rather than trusting a flag written months ago.
A permanent failure: broken structure, no mail route, or an outright rejection from the receiving server. The check did its job; sending anyway earns a hard bounce.
Record the original string and the reason code from the check. Never auto-repair the domain — a corrected guess can belong to a completely different person, and no later check will tell you it went to the wrong one.
The domain accepts every local part, so the SMTP check cannot single out this recipient. Company files built from firstname.lastname patterns are full of these rows.
Keep catch-all as its own bucket. Folding it into valid makes a list look cleaner than it is, and no further check email address run will separate the real recipients from the invented ones.
Greylisting, provider deferrals, and rate limits all produce answers that prove nothing. Unknown is the honest label for them.
Check the address again later rather than writing a false negative into your database. The share of unknowns usually drops sharply on a second check.
Everyday use
This page is built for the single-address question, so it is worth being deliberate about when that question is actually the right one.
A business card, a forwarded introduction, a name typed over the phone. Check email address online once before you write a real message to it and you avoid the awkward silence of a bounce nobody sees.
The check takes about two seconds, which is less time than re-reading the address for typos — and you can check email address for free as often as you need.
Invoices, contracts, password resets, a reply to a warm inbound lead. These are exactly the messages where a bounce costs more than the check, so check email address input before you hit send.
For a whole file rather than one address, Bulk Email Verification applies the identical rules to every row and returns an export with the reasons preserved.
If the same typo patterns keep appearing, the fix is upstream. Check email address input at the point of capture, while the person who knows the right answer is still on the page.
Prototype the check here first, then move the same logic into your signup flow through the API so every new row gets the same check.
Honest limits
The result is trustworthy because its claim is narrow. Each of these belongs somewhere else.
An accepting mailbox proves a mailbox, not a person. Shared aliases, forwarded addresses, and stale contact data all produce a clean check email address result attached to the wrong name.
Use first-party data when ownership matters, and treat any inferred identity as a hypothesis.
A clean check lowers your bounce rate. It does not create consent, and no check consults your suppression list for you.
Keep permission in your own system of record and apply it before, not after, the check.
Whether your message reaches the inbox depends on your sending reputation, authentication, content, and complaint history — none of which a recipient-side check can see.
Check email address input to remove address-level failures, then treat placement as its own discipline with its own metrics.
Where to go next
Every tool here runs the same engine. What changes is the question the page is written around — this one is written around a fast check email address answer.
The Email Verifier is written around proving that a mailbox will accept mail, with the SMTP evidence explained in more depth.
Same engine, different framing — use it when deliverability rather than a quick check email address online look is the point.
The Email Validator stops at syntax and MX and never spends a mailbox query, which makes it the cheap screen for large volumes.
Use it when you only need to check that an address could work, not that it does.
When one address is not enough, Email List Cleaning keeps deduplication, retries, and reason codes consistent across every row of a file.
Check email address behaviour on a sample here first, then run the file once the result makes sense to you. Check email address for free on the sample; pay only for the run.
Paste the address and the tool runs four steps: check email address syntax, check the domain and its MX records, open a direct SMTP connection to check that the mailbox accepts mail, and score the risk flags. Results come back in under 2 seconds.
BillionVerify reaches 99.9% accuracy by combining syntax rules, DNS lookups, MX resolution, and a direct SMTP check. That multi-layer approach catches the invalid, inactive, and risky addresses a single-layer tool misses when it tries to check email address online from format alone.
It detects syntax errors (missing @, invalid characters, malformed structure), unregistered domains, missing MX records, inactive mailboxes, disposable providers, and role-based accounts like info@ and support@. Each one comes back with its own reason code rather than a generic failure.
Yes. Upload a CSV to check thousands of addresses in bulk and download the cleaned file in minutes, or use the real-time API to check email address online as it arrives from your forms or CRM. You can still check email address for free one at a time here.
Yes. Check email address for free with 600 credits a month, plus 20 more every day you log in — no credit card required. The free tier includes every layer: syntax, domain, MX, SMTP, and disposable detection.
No. Every check email address run happens in real time and the address is never stored. Data is encrypted in transit and deleted immediately after processing.
Nineteen free tools alongside the paid AI features, none of them requiring an account.
Email Verify Tools
Check if an email address is valid with a free email verifier, no signup — syntax, MX, SMTP mailbox, disposable, role and catch-all checks.
Recipient evidence — not sender or DNS configuration.
Email Verify Tools
Free email validator for address syntax and published MX records. Run an email syntax and MX check instantly, without claiming SMTP mailbox proof.
Email Verify Tools
Free email spam checker: see whether an address sits on a domain with a recorded spam, phishing, or malware history. Check email for spam risk instantly, no signup.
Email Verify Tools
Free temporary email address detector: spot disposable and throwaway domains in real time, with focused disposable results for signups and list quality.
Email Verify Tools
Free bounce email checker: find out whether an address will hard bounce before you send, with a live SMTP probe. A hard bounce detection tool, no signup.
Email Verify Tools
Email list cleaning service with live SMTP verification on every row: dedupe, suppress hard bounces, keep the reasons. Clean email list free tool, no signup to try.
Check email address for free — 600 credits a month, plus 20 more every day you log in. Full SMTP on every check, in under 2 seconds.
600 free credits monthly · No signup required · Results in under 2 seconds
