What are the best practices for email verification and reducing bounces?

Summary

The best practices for email verification and reducing bounces involve a multifaceted approach encompassing proactive list hygiene, thorough bounce investigation, strategic email authentication, and a focus on subscriber engagement. Email verification helps maintain a clean list by identifying and removing invalid addresses, improving sender reputation and deliverability. Rather than solely relying on verification services, it is crucial to investigate the underlying causes of high bounce rates, such as list age, acquisition methods, and form security. Focusing on opt-in practices and re-engagement campaigns, as well as providing clear unsubscribe options, are critical. Implementing email authentication protocols (SPF, DKIM, DMARC), combined with monitoring engagement metrics to identify and remove unengaged subscribers, further enhances deliverability. The documentation from AWS, SparkPost, and SendGrid, along with the RFC, emphasizes automated bounce handling and the importance of understanding SMTP reply codes for automated error handling. Experts recommend treating list problems as process issues tied to forced sign-ups and outdated addresses, advising against purchasing lists and instead, using activity data for validation.

Key findings

  • Proactive List Hygiene: Maintaining a clean email list by regularly removing invalid or inactive addresses is essential for reducing bounce rates and protecting sender reputation.
  • Thorough Bounce Investigation: Investigate the reasons behind high bounce rates (list age, acquisition method) before using list cleaning services.
  • Strategic Authentication: Implement SPF, DKIM, and DMARC to improve deliverability and sender authentication.
  • Engagement Focus: Monitor engagement metrics to identify and remove unengaged subscribers.
  • Double Opt-In: Implement double opt-in processes to ensure subscribers are genuinely interested.
  • Complaint Management: High soft bounces may indicate a high complaint rate and require a strategy beyond list cleaning.

Key considerations

  • Hard vs. Soft Bounces: Distinguish between hard and soft bounces and handle them differently, removing hard bounces immediately.
  • Process Improvement: Address email list issues as process problems related to forced sign-ups and outdated addresses.
  • Tool Selection: If using email verification tools, choose reputable providers like BriteVerify or Kickbox.
  • Re-engagement: Before removing unengaged subscribers, consider re-engagement campaigns.
  • SMTP Codes: Understand SMTP reply codes to automate bounce processing.
  • Data Security: Secure your email forms with CAPTCHA to protect against list bombing.

What email marketers say
11Marketer opinions

Experts and marketers emphasize the importance of email verification and proactive list management to reduce bounce rates and improve email deliverability. Key strategies include implementing double opt-in processes, regularly cleaning email lists, segmenting subscribers, and monitoring sender reputation. They also advise investigating the underlying causes of bounces, focusing on process improvements over solely relying on verification services, and authenticating emails with SPF, DKIM, and DMARC. Addressing issues like forced sign-ups, outdated addresses, and spam complaints is crucial. Tools like BriteVerify and Kickbox can assist, but proper email list hygiene and understanding bounce reasons are paramount.

Key opinions

  • Email Verification: Email verification is crucial to maintain a clean list, improve sender reputation, and boost deliverability by identifying and removing invalid/risky addresses.
  • Bounce Investigation: Investigate the root causes of bounces (e.g., list age, acquisition method, form security) rather than immediately paying for list cleaning services.
  • Opt-in Practices: Focus on opt-in practices (double opt-in), re-engagement campaigns, and clear unsubscribe options to ensure subscribers want your emails.
  • List Cleaning: Regularly clean email lists by removing invalid, inactive, or unengaged subscribers.
  • Process Improvements: Address email list problems as process issues related to forced sign-ups, outdated addresses, and lack of subscriber engagement.
  • Authentication: Implement email authentication protocols (SPF, DKIM, DMARC) to improve deliverability and sender reputation.
  • Activity Data: Consider using activity data to identify engaged users rather than solely relying on validation services.
  • Bounce Handling: Implement a 'bounce-back' feature to automatically collect and disable further sending to bounced email addresses.

Key considerations

  • Bounce Reasons: Understand the types of bounces (hard vs. soft) and their reasons to take appropriate action (e.g., immediate removal for hard bounces).
  • Complaint Handling: Address spam complaints promptly, as they can negatively impact deliverability even if the email addresses are valid.
  • Tool Selection: If using email verification tools, select reputable providers like BriteVerify or Kickbox.
  • List Bombing: Check for unusual spikes in sign-ups, which might indicate a potential list bomb attack.
  • Unengaged Subscribers: Carefully manage unengaged subscribers - segment and try to re-engage, or remove them if they are not responsive
Marketer view

Marketer from Email Geeks frames email list problems as process issues, often linked to forced sign-ups or retaining addresses for too long.

November 2022 - Email Geeks
Marketer view

Email marketer from Email Hippo Blog details the different types of email verification methods, such as syntax checks, domain checks, SMTP verification, and real-time verification. It outlines the strengths and weaknesses of each method.

November 2024 - Email Hippo Blog
Marketer view

Email marketer from Reddit shares to not buy lists, verify your email sending domain is properly authenticated and to have a very obvious unsubscribe option that works. If people are marking you as spam, then you have a bigger problem.

November 2023 - Reddit
Marketer view

Marketer from Email Geeks recommends diagnosing the root cause of bounces by considering changes in email practices, potential list bombs, form security (COI, reCAPTCHA), and trends in soft and hard bounce reasons before using list verification services.

May 2023 - Email Geeks
Marketer view

Marketer from Email Geeks recommends BriteVerify and Kickbox for email verification and advises focusing on opt-in practices and re-engagement campaigns for better list hygiene.

October 2024 - Email Geeks
Marketer view

Marketer from Email Geeks suggests investigating the reasons behind high bounce rates instead of immediately resorting to list cleaning services and asks what the bounce reasons are, how old the list is and where they obtained the subscribers from.

August 2022 - Email Geeks
Marketer view

Email marketer from ZeroBounce Blog explains strategies to reduce bounce rates, including using a double opt-in process, regularly cleaning email lists, segmenting lists, and monitoring sender reputation. It also suggests authenticating emails with SPF, DKIM, and DMARC.

May 2024 - ZeroBounce Blog
Marketer view

Email marketer from Gmass Blog shares to only mail to verified addresses and not to buy lists. They also share how to remove bounces from the list.

August 2021 - Gmass Blog
Marketer view

Email marketer from StackOverflow contributes that any script you use for sending emails should have a 'bounce-back' feature, where if there is a undeliverable message, your application will collect the 'bounce-back' addresses and disable further sending to that particular address.

July 2023 - StackOverflow
Marketer view

Email marketer from MailerCheck Blog emphasizes the importance of email verification to maintain a clean email list, improve sender reputation, and boost deliverability. It helps in identifying and removing invalid or risky email addresses, preventing bounces and protecting sender reputation.

May 2024 - MailerCheck Blog
Marketer view

Marketer from Email Geeks recommends using activity data instead of a validation service.

September 2024 - Email Geeks

What the experts say
3Expert opinions

Experts highlight the critical role of list hygiene and subscriber engagement in minimizing bounces and enhancing email deliverability. A key point is that soft bounces are often tied to spam complaints, which list cleaning alone cannot fix. Regularly removing invalid or inactive addresses maintains a clean list, while segmenting and removing unengaged subscribers improves overall email performance.

Key opinions

  • Complaint-Driven Bounces: Soft bounces at major providers like Verizon, Gmail, and Microsoft are frequently due to spam complaints and are not resolved by simple list cleaning.
  • List Hygiene: Maintaining a clean email list by regularly removing invalid or inactive email addresses is essential for reducing bounce rates and protecting sender reputation.
  • Subscriber Engagement: Segmenting and removing unengaged subscribers is important for improving overall email performance by focusing efforts on receptive audiences.

Key considerations

  • Complaint Monitoring: Monitor and address spam complaints proactively, as they have a significant impact on deliverability.
  • Segmentation Strategy: Implement a robust segmentation strategy to target engaged subscribers and reduce the likelihood of bounces and complaints.
  • Re-engagement Campaigns: Before removing unengaged subscribers, consider implementing re-engagement campaigns to try and win them back.
Expert view

Expert from Spam Resource emphasizes the importance of maintaining a clean email list by regularly removing invalid or inactive email addresses to reduce bounce rates and improve sender reputation.

December 2023 - Spam Resource
Expert view

Expert from Word to the Wise explains the importance of segmenting and removing unengaged subscribers. By identifying inactives and suppressed addresses it improves overall email performance.

May 2024 - Word to the Wise
Expert view

Expert from Email Geeks explains that many soft bounces, particularly at Verizon, Gmail, and Microsoft, are due to complaints and won't be resolved by list cleaning.

January 2023 - Email Geeks

What the documentation says
4Technical articles

Email service providers like AWS SES, SparkPost and SendGrid emphasize automated bounce handling and list management for deliverability. Understanding the difference between hard and soft bounces is crucial, with hard bounces needing immediate removal and soft bounces warranting further investigation. Authentication via SPF, DKIM, and DMARC is vital, as is monitoring engagement to identify and remove unengaged subscribers. SMTP reply codes provide structured error information for bounce processing.

Key findings

  • Automated Bounce Handling: Email service providers (AWS SES, SendGrid) offer automated bounce handling, simplifying the process of managing bounced emails.
  • Bounce Classification: Distinguish between hard and soft bounces; hard bounces require immediate removal, while soft bounces need investigation.
  • Authentication Protocols: Implement email authentication protocols (SPF, DKIM, DMARC) to improve deliverability.
  • Engagement Monitoring: Monitor engagement metrics to identify and remove unengaged subscribers from your email list.
  • SMTP Reply Codes: SMTP reply codes provide a machine-readable indication of email delivery status, aiding in automated bounce processing.

Key considerations

  • SES Configuration: Properly configure bounce notifications in AWS SES to handle bounces effectively.
  • Removal Strategy: Develop a clear strategy for handling hard and soft bounces, including removal timelines and investigation processes.
  • Subscriber Re-engagement: Before removing unengaged subscribers, consider implementing a re-engagement campaign.
Technical article

Documentation from SendGrid details several techniques for improving email deliverability, including email authentication (SPF, DKIM, DMARC), list management, and monitoring engagement metrics to identify and remove unengaged subscribers.

May 2021 - SendGrid Documentation
Technical article

Documentation from SparkPost defines hard and soft bounces and provides guidance on how to manage them. It notes that hard bounces should be removed immediately, while soft bounces may require temporary suppression or further investigation.

January 2024 - SparkPost Documentation
Technical article

Documentation from AWS explains how to handle bounces in Amazon Simple Email Service (SES) by setting up bounce notifications. It describes the differences between hard and soft bounces and how SES handles them automatically.

December 2021 - AWS Documentation
Technical article

Documentation from RFC explains that SMTP reply codes, also known as enhanced mail system status codes, provide a structured and machine-readable indication of the outcome of an SMTP transaction, aiding in bounce processing and automated email error handling.

February 2024 - RFC