The Definitive Guide to Email Verification
Everything you need to know about cleaning your list, removing hard bounces, and protecting your sender reputation.
Email verification is the process of ensuring that the emails on your list are valid and deliverable. It is the first line of defense against high bounce rates and reputation damage.
Why Verify Emails?
Sending to invalid emails ("hard bounces") signals to ISPs like Google and Outlook that you are a spammer. If your bounce rate exceeds 2-3%, your emails will start landing in the spam folder, even for valid users.
Reduce Bounce Rate
Keep your bounce rate under 1% to maintain a healthy sender score.
Save Money
Don't pay to send emails to addresses that don't exist.
How It Works: The 3-Step Process
Professional verifiers like MailBolt use a sophisticated multi-stage process to check emails without actually sending a message to the recipient.
Syntax Check
Ensures the email follows standard formatting rules (e.g., has an @ symbol, valid characters, and a domain extension). This catches simple typos like "[email protected]".
Domain & MX Record Check
We query the DNS records of the domain to ensure it exists and has valid Mail Exchange (MX) records capable of receiving email.
SMTP Handshake
The most advanced step. We initiate a connection with the mail server and ask, "Does this user exist?" The server responds with a code (250 OK or 550 User Not Found), and we disconnect before sending any data.
Pro Tip: Remove Risky Emails
It's not just about invalid emails. You should also remove "Role-Based" emails (admin@, support@) and "Disposable" emails (mailinator.com) as they typically have very low engagement rates.
When to Verify?
We recommend verifying your list in these scenarios:
- Before importing a new list into your ESP.
- Every 3-6 months for older lists (data decay is real).
- Immediately upon signup using our Real-time API to block bad data at the source.
Ready to clean your list?
Get started with 500 free verifications today. No credit card required.