StopBouncingEmail Validation at Any Scale.
Format. DNS. SMTP. All Three.
Most email validation tools only check format. StopBouncing goes three levels deep — format validation, DNS and MX checking, and live SMTP verification — for every address.
100 free validations. No credit card required.
Three Levels of Email Validation
StopBouncing performs all three levels on every address. Each level catches different classes of invalid emails.
Format Validation
- Valid characters
- @ symbol present
- Domain part exists
- No consecutive dots
Does it look like an email?
Doesn't confirm the domain or mailbox exists.
DNS Validation
- Domain resolves in DNS
- MX records configured
- Mail server reachable
Can the domain receive email?
Doesn't confirm the specific mailbox exists.
SMTP Verification
- SMTP handshake accepted
- Mailbox exists confirmation
- Not a catch-all domain
- Not disposable
Does this specific address deliver?
Catch-all domains cannot be fully confirmed.
Email Validation FAQ
What is email validation?
Email validation checks whether an email address is correctly formatted and potentially deliverable. It ranges from simple syntax checking (does it look like an email?) to full SMTP verification (does the mailbox actually exist on the mail server?). StopBouncing performs all three levels of validation on every address.
What is the difference between email validation and email verification?
Email validation often refers to format/syntax checking. Email verification is a broader term that includes DNS lookups and SMTP confirmation of the mailbox. In practice, the terms are used interchangeably. StopBouncing performs both — we validate the format and verify the deliverability.
How do I validate email addresses in bulk?
Upload your CSV to StopBouncing and we'll validate every address in the file. Our parser automatically detects the email column. After processing, download the results with a status column added — filter by Valid, Invalid, Unknown, or Disposable to get exactly the segment you need.
Can I validate emails via API?
Yes. The StopBouncing REST API validates a single email address per request and returns a JSON response with format, DNS, SMTP, disposable, and catch-all status. The API is suitable for validating addresses at the point of entry in registration forms, checkout flows, or CRM imports.
Validate Your Email List Today
Format check. DNS check. SMTP check. All three. 100 free credits to start.