Email verification

Email verification is the process of checking whether an email address is likely to be deliverable before you send.

It is one of the highest leverage parts of outbound.

A great message sent to a bad address still creates a bounce, and bounces are a direct reputation signal.

Why it matters

• Lower bounce rate
• Fewer spam trap risks
• Better sender reputation over time
• Cleaner attribution (you are not measuring campaigns polluted by invalid contacts)

What verification typically checks

Verification tools usually attempt to detect:

• Invalid syntax
• Non-existent domains
• Mailbox doesn’t exist
• Catch-all domains (higher risk)
• Temporary/disposable addresses

No tool is perfect. The goal is to reduce risk, not guarantee delivery.

Operational rule

If you are running outbound at any meaningful scale:

• Verify every list before sending.
• Suppress hard bounces permanently.
• Treat old data as higher risk (decay is real).

Related terms

• Bounce rate
• Domain reputation
• Data decay