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 #
Our advanced verification system analyzes catch-all email domains and classifies them based on delivery reliability and risk assessment. Catch-all domains accept all incoming email regardless of address validity, requiring careful evaluation for optimal delivery performance.
Deliverable #
Deliverable addresses have undergone comprehensive verification confirming their reliability for email campaigns. These represent the highest confidence level, indicating:
- Verified domain infrastructure with consistent delivery patterns
- Minimal bounce rates and strong sender reputation compatibility
- Recommended for regular sending volumes with confidence
Undeliverable #
Undeliverable addresses have been identified as non-functional through our verification process. These classifications indicate:
- Confirmed non-functional email addresses or domains
- High probability of generating hard bounces
- Should be immediately removed from all sending lists to protect sender reputation
Risky and Low Deliverability #
Risky and Low Deliverability addresses require careful handling due to unpredictable delivery patterns. These addresses exhibit:
- Inconsistent acceptance rates and variable inbox placement
- Limited historical data preventing definitive assessment
- Potential for soft bounces or delivery delay
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.
