What are some poor sending practices to avoid that can cause issues with email deliverability?

Key findings

• Authentication issues: Lack of proper email authentication, such as SPF, DKIM, and DMARC, is a significant red flag for mailbox providers. Without these, your emails are more likely to be seen as spoofed or fraudulent, leading to deliverability problems.
• Poor list hygiene: Sending to invalid, inactive, or spam trap email addresses severely harms your sender reputation. Regularly cleaning your list is crucial.
• Spammy content: Subject lines or email bodies containing excessive capitalization, exclamation marks, suspicious phrases, or image-only content can trigger spam filters.
• Volume spikes: Sending large volumes of emails from a new or cold IP/domain without a proper warm-up strategy can be perceived as spamming behavior, leading to immediate blocklisting or throttling.
• High complaint rates: When recipients mark your emails as spam, it directly impacts your sender reputation. This often stems from poor segmentation, irrelevant content, or unclear unsubscribe options.

Key considerations

• Domain and IP reputation: Your sending reputation is built over time based on your sending habits. A damaged reputation can lead to emails being sent to spam or rejected. Consistent good practices are key to maintaining a healthy domain reputation.
• Engagement metrics: Low open rates and click-through rates, coupled with high bounce and complaint rates, signal disinterest and can hurt your deliverability. Focus on engaging content and a relevant audience.
• Blocklist status: Being listed on an email blacklist (or blocklist) will severely impact your deliverability. You should proactively monitor your blocklist status to identify and address issues quickly. More details on how poor sending practices trigger informational listings can be found directly from Spamhaus.
• Content quality: Beyond spam triggers, ensure your content provides value and aligns with subscriber expectations. Irrelevant or poorly designed emails lead to low engagement and higher unsubscribe rates.
• Sending frequency: Sending too frequently can lead to subscriber fatigue and increased complaints, while sending too infrequently can result in low engagement and stale lists.

Key opinions

• List acquisition quality: Improperly gathering subscribers, such as purchasing lists or using single opt-in without verification, is a common reason for poor deliverability.
• Image-only emails: Sending emails that are entirely image-based or image-heavy is a significant red flag for spam filters because it's a technique often used by spammers for image mapping.
• From address mismatch: Using a 'from email' address that does not align with your primary sending domain can lead to poor deliverability and authentication issues.
• Spam trap hits: Hitting spam traps, often due to outdated or purchased lists, immediately damages sender reputation and can lead to being added to a blacklist.

Key considerations

• Subscriber re-engagement: Even with long-term subscribers, it can be beneficial to periodically ask for re-confirmation, such as a click-on-a-link-to-ensure-you-still-get-mail approach, to maintain an engaged list.
• Engagement pacing: Sending too frequently causes email fatigue and can lead to high unsubscribe and spam complaint rates. Finding the right frequency is key for sustained deliverability and positive sender reputation.
• Domain authentication: Sending without an authenticated domain is a major factor that hurts deliverability. Custom authentication (SPF, DKIM, DMARC) is seen as a foundational step to avoid being perceived as a spammer.
• IP warm-up: For new or inactive accounts, starting with a limited number of emails and gradually increasing volume (warming up the IP) is vital to avoid triggering spam filters.

Key opinions

• Reputation is paramount: A low IP or domain reputation is the most common reason emails are filtered to spam. This underscores the need for consistent good sending behavior.
• Authentication is non-negotiable: Properly configured SPF, DKIM, and DMARC records are crucial for establishing sender trust with ISPs. Without them, even legitimate emails face deliverability challenges.
• Bounce management: Ignoring bounces, especially hard bounces, leads to sending to invalid addresses, which negatively impacts sender reputation and can lead to blocklisting.
• Spam trap avoidance: The best way to avoid spam traps is through stringent email address verification upon collection and ongoing list hygiene.

Key considerations

• Gradual volume increases: Experts advise against sudden bulk sending from new or dormant IPs, recommending a structured warm-up process to build a positive sending history.
• Engagement monitoring: Consistently low engagement rates, coupled with high complaint rates, are strong indicators of poor sending practices or an unengaged audience. This can be mitigated by focusing on improving email click-through rates.
• Content relevance: Beyond technical aspects, the relevance and quality of email content play a significant role. Irrelevant content increases the likelihood of complaints and low engagement.
• Feedback loops: Utilizing feedback loops from ISPs helps identify and remove users who mark emails as spam, preventing further deliverability issues for those recipients.
• Ongoing monitoring: Regularly checking email blacklists and monitoring domain reputation through tools like Google Postmaster Tools is essential for early detection and remediation of deliverability problems.

Key findings

• Authentication is standard: Documentation consistently stresses the importance of proper email authentication (SPF, DKIM, DMARC) as a basic requirement for trusted sending.
• Consent and list quality: Clear opt-in processes and ongoing list hygiene, including promptly handling bounces and unsubscribes, are fundamental to maintain good sender reputation.
• Content best practices: Documentation often provides guidelines on subject line creation, text-to-image ratios, and avoiding spammy keywords to prevent content-based filtering.
• Volume management: New senders or those with fluctuating volumes are advised to follow IP warm-up procedures to gradually build trust with mailbox providers.

Key considerations

• Reputation tracking: Understanding and actively monitoring your sender reputation, often through postmaster tools, is highlighted as crucial for identifying and addressing issues.
• User engagement metrics: High complaint rates, low engagement, and high bounce rates are clear signals of poor sending practices that need immediate attention. Regular email deliverability tests can help identify these.
• Feedback loop implementation: Setting up and responding to ISP feedback loops allows senders to automatically remove users who complain, preserving sender reputation.
• Monitoring blocklists: Documentation often recommends regular checks against major blacklists and understanding the reasons for listings, as detailed by sources like Spamhaus Technology.