Stop sending to dead, risky, or fake addresses. BounceZero checks syntax, MX records, and real mailbox existence over SMTP — plus catch-all, disposable, and spam-trap detection — in real time with 99.8% accuracy.
Email verification is the process of confirming that an email address is legitimate, active, and deliverable before you add it to your list or send to it. It goes far beyond a simple format check: it validates the address against the actual mail infrastructure and flags addresses that will bounce or harm your sender reputation.
A good email list is your most valuable marketing asset. Every invalid address you send to lowers your deliverability, inflates your bounce rate, and can get your domain blacklisted. Verification protects your sender reputation and your budget.
BounceZero runs every address through a multi-stage pipeline that combines 65+ signals into a single confidence verdict.
Is the address formatted correctly? Missing @, invalid characters, or malformed local parts are rejected immediately.
Does the domain have mail servers at all? A domain with no MX records cannot receive email — the address is dead on arrival.
Connect to the mail server and observe its RCPT response. A 550 means the mailbox doesn't exist; an accept confirms it does.
Some domains accept mail to any address. BounceZero flags these so you know the mailbox couldn't be individually confirmed.
Known honeypot addresses and throwaway providers are flagged before they can poison your list or hurt your reputation.
All signals combine into a single verdict — valid, invalid, or risky — so you know exactly what to do with every address.
Every tool below is free for single checks — no login required. Pick the one that matches what you're checking.
Full verification — syntax, MX, SMTP mailbox existence, catch-all, disposable, and spam traps.
Check an address →Quick validity check focused on format, MX, and deliverability for a single address.
Validate →Check whether an email is valid or will bounce — quick verdict plus the key signals behind it.
Check →Detects all three trap types — pristine, recycled, and typo — before they hit your list.
Check for traps →Low-level SMTP test that shows exactly what the mail server responds for a given address.
Run SMTP test →Verify addresses at scale — real-time API or bulk CSV upload, 100 free credits to start.
See the API →Mailbox providers track bounces. Cross 2% and your sender reputation drops — crossing 5% can get you blacklisted. Verification keeps bounces near zero.
Every address you pay to send to that bounces is wasted spend. Verification pays for itself on the first campaign.
One trap can tank your domain reputation overnight. Verification flags known traps before you send.
Higher open and click rates follow a verified list, which improves engagement and keeps your domain healthy long term.
Email verification checks whether an address is legitimate and deliverable before you send to it — validating syntax, MX records, mailbox existence over SMTP, and flagging catch-all, disposable, and spam-trap addresses.
The verifier connects to the recipient's mail server over SMTP and observes its responses to MAIL FROM and RCPT TO. A server that accepts the recipient confirms the mailbox exists; a 550 rejection means it does not.
A catch-all domain accepts mail to any address, so SMTP checks alone can't confirm a specific mailbox. BounceZero detects catch-all behavior and flags those addresses rather than guessing.
Yes — single checks are free with no login on the Free Email Verifier. For bulk verification or API access, create a free BounceZero account and get 100 credits, no credit card required.
Upload a CSV or plug in the API. 100 free credits, no card needed - and your first list clean is on us.
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