Should I block disposable email addresses from my email list?

Key findings

• Temporary nature: Disposable email addresses are created for limited use, often expiring quickly (e.g., 24 hours), which can lead to high hard bounce rates if you attempt to send ongoing communications.
• User intent: Users typically employ DEAs for privacy protection, to avoid future unwanted emails, or to access immediate benefits like discount codes without committing their primary email address.
• Deliverability impact: Sending to DEAs that quickly expire or become inactive can negatively affect your email deliverability by increasing bounces and potentially flagging your sender reputation.
• Potential customers: While many DEA users are not long-term prospects, some might be hesitant at first and could convert into loyal customers if given the opportunity, especially for transactional communications.

Key considerations

• List hygiene: Proactively blocking DEAs can help maintain a cleaner email list, reducing unnecessary sending costs and improving overall list quality, which is crucial for long-term email program health.
• Conversion opportunity: Consider if a portion of these users, despite using a DEA, might be interested in your offerings and could be encouraged to provide a primary email address through incentives or tailored content.
• Resource utilization: Sending emails costs money. Continuously sending to addresses that will hard bounce or never engage is a waste of resources and can negatively impact your email service provider relationship.
• Reputation management: High bounce rates from DEAs can lead to your IP or domain being placed on email blacklists or blocklists, severely impacting future inbox placement for all your emails. For more information, you can read this Kickbox blog post.

Key opinions

• Single-use utility: Many marketers believe DEAs are primarily for single, temporary uses, and subscribers using them are not interested in ongoing engagement.
• Cost and deliverability savings: Blocking DEAs is seen as a way to reduce sending costs, prevent hard bounces, and protect sender reputation, thus improving overall email deliverability rates.
• Conversion potential: Some argue that blocking might deter potential loyal customers who are initially hesitant to use their primary email, especially if they are seeking a one-time benefit like a discount voucher.
• Fraud prevention: Marketers recognize that DEAs are often used to bypass security checks, register for multiple accounts, or engage in fraudulent activities like list bombing.

Key considerations

• Strategic filtering: Instead of an outright block, some marketers advocate for flagging DEAs and adapting content to encourage users to provide a primary email address, especially for transactional communications.
• Resource investment: The decision to send to DEAs or attempt conversion depends on the organization's expected customer lifetime value and the cost of email verification services.
• Updated blocklists: Marketers frequently use regularly updated lists of disposable email domains to proactively prevent sending to them, saving costs and avoiding deliverability impacts.
• Bounce management: An abundance of hard bounces from DEAs signals a need for stricter signup form validation and a more aggressive strategy to remove bad email addresses.

Key opinions

• Reputation risk: Experts consistently highlight that sending to DEAs can lead to increased bounce rates, potentially harming your sender reputation and potentially causing your domain or IP to be added to blacklists.
• Minimal long-term value: The consensus is that users of disposable addresses rarely convert into engaged, long-term subscribers, making efforts to market to them largely inefficient.
• Spam trap avoidance: Many disposable domains can evolve into spam traps, making it crucial to avoid them to prevent severe deliverability penalties.
• Proactive hygiene: Experts advocate for proactive list hygiene, including validation at signup and regular cleaning, to prevent DEAs from entering and degrading the quality of your mailing list.

Key considerations

• Email validation services: Utilizing real-time email validation services at the point of signup is highly recommended to identify and block disposable addresses effectively.
• Cost efficiency: The long-term costs associated with poor list quality (e.g., lower inbox rates, increased support) often outweigh the perceived benefits of allowing DEAs.
• User experience vs. deliverability: While respecting user privacy is important, the negative impact on deliverability from DEAs often makes strict blocking a necessary trade-off for overall email program health.
• Long-term strategy: Focus on attracting genuinely engaged subscribers who provide their primary email addresses for sustainable and effective email marketing. For more insights into email verification, you can refer to this MailMonitor article.

Key findings

• Short-lived nature: Documentation confirms DEAs are designed to be temporary, with inboxes that may automatically delete messages or expire after a short period, leading to eventual hard bounces.
• Risk to deliverability: Technical guides often point out that a high volume of DEAs on a list can significantly increase bounce rates, negatively impacting sender reputation and potentially triggering ISP blocklists.
• Fraud and abuse vector: Research highlights DEAs as tools for bypassing registration limits, creating fake accounts, or conducting other malicious activities due to their anonymity and transient nature.
• Detection through APIs: Many technical documents recommend integrating email validation APIs that leverage extensive databases of known disposable domains to identify and block these addresses in real time during signup.

Key considerations

• Validation at signup: The primary recommendation is to implement stringent email validation at the point of user registration to prevent DEAs from ever entering your database. This is a crucial step in preventing bad signups.
• Dynamic blocklists: Given the continuous emergence of new disposable email providers, documentation often advises using dynamically updated blocklists or verification services to stay current with new DEA domains.
• Impact on engagement metrics: Documentation frequently details how DEAs distort engagement metrics (open rates, click-through rates) and lead to inaccurate assessments of campaign performance.
• Security posture: From a security perspective, technical documentation highlights that preventing disposable email addresses from registering helps protect signup forms from bots and reduces overall fraud risk. For further reading, consult the MyEmailVerifier blog.