Mailmark
Tools/Email List Validator

Free Email List Validator - Verify Emails Before You Send

Check your email list for invalid addresses, disposable emails, and risky contacts. Reduce bounces and protect your sender reputation.

Paste up to 100 emails or upload a CSV. Free, no signup required.

One email per line, or comma/semicolon separated. Max 100.

.csv or .txt files supported

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Frequently Asked Questions

Why should I validate my email list before sending?

Sending to invalid emails causes hard bounces, which damage your sender reputation. A bounce rate above 2% can trigger spam filters and get your domain blacklisted. Validating your list removes bad addresses before they hurt your deliverability.

What counts as a 'risky' email?

Role-based addresses (info@, admin@, support@) and free provider emails (Gmail, Yahoo) are flagged as risky. Role-based addresses are shared inboxes that often have stricter spam filtering. Free providers are fine for personal outreach but may indicate low-quality B2B leads.

How often should I clean my email list?

Clean your list every 3-6 months, or before any major campaign. Email addresses decay at roughly 2-3% per month as people change jobs, companies shut down, and domains expire. Regular cleaning keeps your bounce rate low.

What's the difference between syntax validation and MX record checking?

Syntax validation checks if the email format is correct (has an @ sign, valid characters, etc.). MX record checking verifies that the domain actually has mail servers configured to receive email. An email can have valid syntax but still be undeliverable if the domain has no mail server.

Can I upload a CSV file?

Yes. Upload a CSV file and we will extract email addresses from it automatically. We look for columns named 'email', 'Email', 'email_address', or similar. You can also paste emails directly into the text box, one per line.