StopBouncingEmail Validator — Beyond Format Checks
Most email validators only check the format. StopBouncing validates syntax and performs live DNS, MX, and SMTP checks to confirm the address actually delivers. Know before you send.
100 free validations on signup. No credit card required.
What We Check for Every Email
A valid email address passes all six checks. Each check catches a different class of problem that a simple format regex cannot detect.
Full explanation of each checkEmail Validation vs. Email Verification
The terms are often used interchangeably, but they describe different levels of checking.
| Check | Validation only | StopBouncing |
|---|---|---|
| Format check (syntax) | ||
| Domain DNS lookup | ||
| MX record check | Sometimes | |
| SMTP mailbox check | ||
| Disposable detection | ||
| Catch-all detection | ||
| Role account flagging |
Why Format Checking Alone Is Not Enough
A regex email validator can confirm that user@domain.com looks like an email address. It cannot confirm whether domain.com has a mail server, or whether the mailbox user has ever existed.
According to industry data, between 15% and 30% of email addresses in an average database are invalid or undeliverable — even if they were collected via a validated form field. People change jobs, close email accounts, or use temporary addresses that expire within hours.
Email service providers like Mailchimp, Klaviyo, and SendGrid monitor your bounce rate. Exceeding the 2% hard bounce threshold can result in account suspension. A full SMTP verification catches these before they reach your sending infrastructure.
Protect your sender reputation
High bounce rates damage your domain's sending reputation with Gmail, Outlook, and every major inbox provider.
Improve email deliverability
A clean list means more messages reaching the primary inbox instead of spam folders or rejection queues.
Reduce wasted sending cost
Most email platforms charge per send. Removing invalid addresses saves money on every campaign.
Email Validator FAQ
What is the difference between email validation and email verification?
Email validation typically refers to checking whether an address is correctly formatted (syntax). Email verification goes further: it checks DNS records, MX configuration, and performs an SMTP handshake to confirm the mailbox actually exists. StopBouncing does both.
Can I validate email addresses for free?
Yes. Every new account at StopBouncing includes 100 free credits for email validation and verification. No credit card is required to get started. Additional credits are available from €0.0005 per email.
How accurate is email format validation?
Syntax validation is 100% accurate — an address either matches the RFC 5321 specification or it does not. However, a syntactically valid email address can still be undeliverable if the domain doesn't exist or the mailbox has been deleted. SMTP verification is required to confirm deliverability.
Can I validate email addresses in bulk?
Yes. Upload a CSV file from your dashboard and validate your entire email list at once. Results include a status column that can be filtered by valid, invalid, unknown, or disposable.
Validate Your First 100 Emails Free
Syntax check + DNS + MX + SMTP verification. All six checks. No credit card required.