Valid #
Email addresses verified as deliverable through our verification system. These addresses have confirmed mailbox existence and active server responses with bounce rates under 2%.
Valid addresses achieve 95%+ inbox placement rates that make them the most reliable contacts for email delivery. Use these addresses for all campaign types, including primary marketing communications and time-sensitive messages.
- Address is valid – The email address is active and accepting incoming mail.
- Service is ready – The mail server is operational and available to receive mail.
- User not local; will forward – The email address exists, but messages are forwarded to another address. The forwarding setup is properly configured and functional, which ensures the message delivery to the intended destination reliably.
Invalid #
Email addresses that cannot receive mail due to various technical or configuration issues. These addresses will generate hard bounces and should be removed immediately from all mailing lists.
- Failed_syntax_check – The email address format is incorrect and doesn’t follow standard email syntax rules (missing @, invalid characters, improper formatting).
- Possible_typo – The address contains common typing errors or suspicious patterns that suggest user input mistakes (e.g., gmial.com instead of gmail.com).
- Mailbox not found – The specific mailbox doesn’t exist on the mail server, though the domain may be valid.
- No_dns_entries – The domain has no mail exchange (MX) records or DNS configuration, which makes email delivery impossible.
- Mailbox_quota_exceeded – The recipient’s mailbox is full and cannot accept new messages until space is freed.
Catch All #
Domains configured to accept all email regardless of specific address validity. The server responds positively without confirming individual mailbox existence. This makes validation impossible without live testing.
Approximately 65% of catch-all addresses successfully receive emails, though results vary by domain. These addresses present a moderate risk with unpredictable engagement patterns; segment separately with reduced sending frequency.
Spamtrap #
Internet service providers and anti-spam groups set up these email addresses to detect and track suspicious or abusive senders. Our detection system uses pattern analysis and industry intelligence to identify these monitoring addresses.
Sending to spamtraps causes immediate deliverability problems and reputation damage, requiring 3-6 months of recovery time. Remove these addresses immediately from all marketing lists and suppression files.
Do Not Mail #
Addresses explicitly marked for exclusion from marketing communications due to previous complaints, legal requirements, or internal suppression policies.
Never send marketing messages to these addresses to maintain sender reputation and legal compliance.
- Role_based – Organizational addresses serving departmental functions (sales@, info@, support@) rather than individual recipients.
- Disposable – Temporary addresses from disposable email providers that expire automatically.
Unknown #
Addresses that cannot be validated due to technical barriers like offline servers or security filtering. Testing indicates approximately 80% of unknown addresses are non-deliverable.
These represent high-risk contacts where validation is blocked by server restrictions rather than confirmed deliverability. Use with caution and minimal sending volumes for testing before regular campaigns.
- Processing_error – Technical failures during the validation process that prevent accurate classification.
- Server_busy – The recipient’s mail server is temporarily unavailable or experiencing high load.
- Temporary_failure – Server is temporarily unable to process validation requests.
- Unexpected_result – Server response doesn’t fit standard classification categories due to unusual configuration.
- NULL – Empty or missing email address fields in your data.
