Free Email Address Validator

What this tool checks

• Syntax — does the address match the email RFC pattern?
• MX lookup — does the domain have mail servers configured?
• Disposable — is the domain a known throwaway service (Mailinator, Yopmail, etc.)?
• Free provider — is the domain a consumer provider (Gmail, Yahoo) — fine for personal contact, risky for B2B leads?

This is a fast in-browser check using Cloudflare's public DNS-over-HTTPS resolver. For deeper verification — SMTP probe, catch-all detection, spam-trap heuristics — use the full BounceBlocker validator.

Why validation matters

Sending to bad email addresses damages your sender reputation in two ways:

• Hard bounces — Gmail, Outlook, and Yahoo track your bounce rate. Once you cross ~2%, they start sending your legitimate mail to spam.
• Spam traps — old, abandoned addresses that ISPs use to catch lazy senders. One spam-trap hit and your IP can land on a blacklist.

What this tool doesn't do

A few things we can't check from your browser alone:

• SMTP probe — actually knock on the mail server and ask "does this mailbox exist?" Requires server-side validation.
• Catch-all detection — some domains accept all addresses, even fake ones. Requires multiple SMTP probes.
• Spam-trap heuristics — requires correlated signals across millions of validations.

Need all of the above + bulk processing? Try BounceBlocker free.

Related tools

• SPF Checker
• DMARC Checker
• DKIM Checker