Summary
Experts and marketers recommend distinct strategies for handling `do_not_send`, `catch_all`, and `unknown` email verification results. `Do_not_send` addresses should be immediately removed to protect sender reputation. `Catch_all` addresses need careful management: segmentation, monitoring engagement, incentivizing users to provide specific addresses, and filtering strategies. `Unknown` results warrant retries and implementing a double opt-in process. Proceed with caution when handling 'risky' addresses by monitoring engagement and using additional verification steps. Email validation should follow general recommendations for maintaining deliverability, data quality, and legal compliance. Consider the risk of frustrating users by incorrectly rejecting valid catch-all addresses.
Key findings
- Immediate Removal of Invalid Addresses: `Do_not_send` (invalid) addresses should be removed immediately to maintain sender reputation.
- Careful Management of Catch-Alls: `Catch_all` addresses require segmentation, monitoring, and strategies to obtain more specific addresses.
- Retry Unknown Addresses: `Unknown` addresses should be retried or subjected to double opt-in.
- Caution with Risky Addresses: Treat 'risky' addresses with caution, monitoring engagement and potentially using additional verification.
- Importance of Validation: Email validation processes have to consider deliverability, data quality, and legal compliance.
Key considerations
- Sender Reputation: Protect sender reputation by promptly removing invalid email addresses.
- User Experience: Balance deliverability needs with potential user frustration from rejecting valid catch-all addresses.
- Data Quality: Improve data quality through client-side and server-side validation.
- Engagement Monitoring: Monitor engagement from catch-all addresses to identify and remove unengaged users.
- Legal Compliance: Ensure email validation processes comply with relevant legal requirements.
What email marketers say
10 marketer opinions
Email marketers generally advise cautious handling of email verification results like `do_not_send`, `catch_all`, and `unknown`. For `do_not_send`, immediate removal is recommended to protect sender reputation. `Catch_all` addresses should be segmented and monitored for engagement, with consideration for incentives to obtain specific addresses. `Unknown` results warrant retries and implementation of double opt-in. Overall, strategies should aim to balance data quality and deliverability, often involving a combination of verification, monitoring, and engagement-based list hygiene.
Key opinions
- Do Not Send: Addresses flagged as `do_not_send` should be immediately removed from mailing lists to avoid bounces and protect sender reputation.
- Catch-All Monitoring: Carefully monitor engagement from `catch_all` addresses due to potential spam traps and low engagement.
- Unknown Retries: `Unknown` results should be retried, as they often indicate temporary issues, and a double opt-in process should be considered.
- Segmentation: Segmenting lists based on email verification results allows for tailored sending strategies and improved deliverability.
Key considerations
- Sender Reputation: Maintaining a clean and engaged email list is crucial for protecting sender reputation and ensuring high deliverability.
- Data Quality: Implementing both client-side and server-side validation can help improve data quality from the point of capture.
- Double Opt-In: Using double opt-in can verify email addresses and increase engagement.
- Engagement Metrics: Monitoring engagement metrics and removing inactive addresses prevents being flagged as a spammer.
Marketer view
Email marketer from Stack Overflow shares to immediately reject invalid email addresses to reduce bounces and protect sender reputation. Suggests using client-side and server-side validation.
31 Dec 2024 - Stack Overflow
Marketer view
Email marketer from Validity Knowledge Base explains that catch-all domains can accept all emails sent to them regardless of mailbox existence. They suggest careful monitoring of these addresses due to the risk of spam traps and low engagement.
26 Mar 2022 - Validity Knowledge Base
What the experts say
4 expert opinions
Experts highlight the challenges and considerations for handling different email verification results. One perspective expresses frustration when valid catch-all addresses are rejected. Another suggests suppressing disposable email domains when focusing on long-term relationships. Additionally, experts emphasize the need for filtering strategies to maintain deliverability with catch-all addresses and highlight the importance of deliverability, data quality, and legal compliance when validating emails.
Key opinions
- Catch-All Frustration: Valid catch-all addresses are sometimes incorrectly rejected, causing user frustration.
- Disposable Domain Suppression: Suppressing emails from disposable domains can be a strategy for focusing on long-term customer relationships.
- Filtering Catch-Alls: Strategies are needed to filter catch-all addresses and maintain deliverability.
- Validation Importance: Email validation requires attention to deliverability, data quality, and legal compliance.
Key considerations
- Balance Rejection and Acceptance: Balance the need to reject potentially harmful addresses with the risk of rejecting valid ones.
- Relationship Goals: Tailor email handling strategies based on the desired type of customer relationship.
- Deliverability Impact: Implement filters for catch-all addresses to minimize negative impacts on deliverability.
- Holistic Validation: Consider all aspects of email validation, including deliverability, data quality, and legal compliance.
Expert view
Expert from Email Geeks shares a GitHub list of disposable email domains and describes a past strategy of quietly suppressing addresses from those domains when relationship-building was the goal.
28 Jun 2022 - Email Geeks
Expert view
Expert from Word to the Wise explains that with catch-all addresses, it is important to implement strategies to filter for invalid addresses and maintain deliverability. Suggests further analysis.
10 Dec 2022 - Word to the Wise
What the documentation says
4 technical articles
Email verification API documentation from various providers (Mailgun, Kickbox, Abstract API) outlines different statuses like 'deliverable', 'undeliverable', 'risky', 'unknown', 'valid' and 'invalid'. They generally advise against sending to 'undeliverable' or 'invalid' addresses. For 'risky' or similar addresses, caution and engagement monitoring or additional verification steps (e.g., confirmation emails) are recommended. Kickbox also emphasizes using result codes for list segmentation and tailored sending. The RFC documentation outlines the technical specifications of an email address syntax.
Key findings
- Undeliverable Rejection: Email addresses categorized as 'undeliverable' or 'invalid' should not be sent to.
- Risky Caution: Addresses flagged as 'risky' require a cautious approach, including monitoring engagement.
- Additional Verification: Confirmation emails and other verification steps are useful for addresses categorized as 'risky' or 'unknown'.
- Segmentation: Email verification results (e.g., from Kickbox) can be used to segment lists and tailor sending strategies.
Key considerations
- Status Definitions: Understand the specific definitions of each status provided by the email verification API.
- Actionable Steps: Establish a clear process for handling each type of email verification result.
- Syntax Compliance: Ensure email addresses adhere to defined syntax requirements.
- Integration with Sending Strategy: Integrate email verification data into the overall email sending strategy.
Technical article
Documentation from Mailgun details that the Mailgun Email Verification API provides statuses like 'deliverable', 'undeliverable', 'risky', and 'unknown'. For 'risky' addresses, they suggest proceeding with caution and monitoring engagement. They recommend not sending to 'undeliverable' addresses.
30 Jul 2023 - Mailgun
Technical article
Documentation from Kickbox clarifies that their service provides detailed result codes, including information about disposable emails, accept-all addresses, and invalid syntax. They suggest using this information to segment lists and tailor sending strategies.
28 Dec 2023 - Kickbox
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