Email Verification Glossary: Terms Explained 2026

This comprehensive glossary defines all key terms related to email verification, helping you understand the terminology used in email marketing and verification services.

A-C

API (Application Programming Interface)

A set of protocols that allows applications to communicate with email verification services programmatically.

Bounce

An email that cannot be delivered to the recipient. See reduce bounce rate guide.

Bulk Verification

The process of verifying multiple email addresses at once, typically used for large email lists. See bulk verification tips.

D-F

Deliverability

The ability of an email to reach the recipient's inbox rather than being filtered as spam or bouncing.

Disabled

An email account status indicating the account has been disabled by the email provider, usually due to policy violations.

Domain

The part of an email address after the @ symbol (e.g., gmail.com in [email protected]).

G-L

Hard Bounce

A permanent email delivery failure, typically due to an invalid email address or non-existent domain.

Live

An email account status indicating the account exists, is active, and can receive emails. This is the best status for email marketing.

M-R

MX Record

Mail Exchange record - a DNS record that specifies which mail server is responsible for accepting emails for a domain.

Rate Limiting

Restrictions on the number of API requests that can be made within a specific time period to prevent abuse.

S-U

Sender Reputation

A score assigned to email senders based on their sending history, bounce rates, and spam complaints. Higher reputation improves deliverability.

Soft Bounce

A temporary email delivery failure, often due to a full mailbox or server issues. These may resolve themselves.

Unregistered

An email account status indicating the email address does not exist on the domain.

V-Z

Verification

The process of checking if an email address exists and can receive emails. See verification vs validation.

Verify Required

An email account status indicating the account exists but requires additional verification steps before it can receive emails.

Webhook

An HTTP callback that sends event notifications to another application. Availability and payload formats depend on the verification provider.