How do email volume and volume fluctuations affect deliverability and sender reputation?

Summary

Maintaining consistent email volume is crucial for establishing and maintaining a positive sender reputation. While volume itself doesn't directly impact reputation, inconsistencies and sudden fluctuations, especially when starting out or during IP warming, can cause deliverability issues as they may be perceived as suspicious activity. Gradual and controlled volume increases are recommended. High spam complaint rates, even with low percentages, can significantly damage reputation at high volumes. Maintaining good list hygiene, proper segmentation, adhering to sending limits, and focusing on sending wanted emails to encourage engagement are all important factors.

Key findings

  • Volume Indirect Impact: While volume itself doesn't directly affect reputation, negative interactions drive poor reputation.
  • Fluctuation Issues: Fluctuations in email volume can cause problems, especially when beginning.
  • Consistent Volume Builds Trust: Consistent email volume builds trust with mailbox providers and helps establish a sender reputation.
  • Spam Rate Sensitivity: Low spam rates are crucial, especially with high email volume, as even small percentages can damage reputation.
  • Sudden Increase Risk: Sudden increases in email volume can trigger spam filters and be interpreted as suspicious activity.
  • List Hygiene Importance: Maintaining good list hygiene, especially at high volumes, is critical to avoid damaging sender reputation.
  • Segmentation Needed: Higher email volumes require careful segmentation and targeting to ensure relevance.
  • Sending Limits Matter: Exceeding sending limits set by email providers or ISPs can result in deliverability issues.
  • Incremental Volume Key: RFC 5321 advises against sudden large increases, recommending incremental increases for a solid reputation.

Key considerations

  • Monitor Fluctuations: Monitor email sending for fluctuations, especially early on, and address any sudden spikes or drops.
  • Gradual Volume Adjustment: Avoid sudden spikes in sending volume and opt for gradual increases, especially during IP warming.
  • Warm IPs Properly: Implement IP warming best practices when setting up new sending infrastructure, increasing gradually.
  • Clean Your List: Regularly clean your email list to remove invalid or unengaged addresses.
  • Segment Audience: Segment your audience to send relevant content to engaged subscribers, minimizing spam complaints.
  • Adhere to Limits: Adhere to sending limits set by email providers and ISPs.
  • Monitor Performance: Monitor email performance metrics (e.g., open rates, click-through rates, spam complaints) to identify and address any deliverability issues.
  • Focus on Engagement: Prioritize sending wanted emails to encourage positive engagement and avoid being marked as spam.

What email marketers say
8Marketer opinions

Maintaining consistent email volume is crucial for building a positive sender reputation. Sudden spikes or drops in volume, especially when starting, can be perceived as suspicious activity and lead to deliverability issues. Proper list hygiene, segmentation, and adherence to sending limits are essential, particularly at high volumes, to minimize spam complaints and maintain engagement. Gradual increases in volume are recommended to establish trust with ISPs.

Key opinions

  • Volume Consistency: Consistent email volume builds trust with mailbox providers and helps establish a sender reputation.
  • Sudden Volume Changes: Sudden spikes or drops in volume can negatively impact deliverability as they may be perceived as suspicious.
  • Initial Sending: Sending too many emails too quickly, especially when first starting, can lead to deliverability problems.
  • List Hygiene: Maintaining good list hygiene, especially at high volumes, is critical to avoid damaging sender reputation.
  • Segmentation: Higher email volumes require careful segmentation and targeting to ensure relevance and minimize spam complaints.
  • Sending Limits: Exceeding sending limits set by email providers or ISPs can result in deliverability issues.
  • Engagement Impact: A sudden increase in frequency and volume can damage your sender reputation and affect deliverability, especially if recipient engagement is low.

Key considerations

  • Monitor Volume: Monitor your email sending volume to identify and address any sudden spikes or drops.
  • Warm-Up IPs: Gradually increase your email volume to warm up new IP addresses and build a positive sender reputation.
  • Clean Your List: Regularly clean your email list to remove invalid or unengaged addresses.
  • Segment Your Audience: Segment your audience to send relevant content to engaged subscribers.
  • Adhere to Limits: Adhere to sending limits set by email providers and ISPs.
  • Monitor Performance: Monitor email performance metrics (e.g., open rates, click-through rates, spam complaints) to identify and address any deliverability issues.
Marketer view

Email marketer from Litmus states that maintaining good list hygiene is critical, especially at high volumes. Sending to invalid or unengaged addresses increases bounce rates and spam complaints, damaging your sender reputation.

August 2021 - Litmus
Marketer view

Email marketer from SendPulse shares that maintaining a consistent sending volume builds trust with mailbox providers. This predictability helps them identify you as a legitimate sender, positively impacting your reputation.

March 2024 - SendPulse
Marketer view

Email marketer from Mailjet explains that consistent email volume helps establish a sender reputation with ISPs. Sudden spikes or drops in volume can negatively impact deliverability as they may be perceived as suspicious activity.

November 2021 - Mailjet
Marketer view

Email marketer from Warrior Forum states that a sudden increase in frequency and volume can damage your sender reputation and affect deliverability, especially if the recipient engagement is low. Gradual increases alongside monitoring performance is important.

April 2022 - Warrior Forum
Marketer view

Email marketer from GMass explains that exceeding sending limits set by email providers or ISPs can result in deliverability issues. It's important to adhere to these limitations and gradually increase sending volume as your reputation grows.

January 2024 - GMass
Marketer view

Email marketer from EmailToolTester explains that sending too many emails too quickly, especially when first starting, can lead to deliverability issues. ISPs may see this as spammy behavior and throttle or block your emails.

October 2024 - EmailToolTester
Marketer view

Email marketer from GlockApps answers that higher email volumes require careful segmentation and targeting. Sending relevant content to engaged subscribers minimizes spam complaints and improves deliverability.

January 2025 - GlockApps
Marketer view

Email marketer from Reddit's r/emailmarketing mentions that inconsistent sending patterns (large spikes/drops) can make it harder for ISPs to trust your mail stream, leading to filtering issues. A stable, predictable volume is generally preferred.

September 2024 - Reddit

What the experts say
5Expert opinions

While volume itself doesn't directly impact reputation, inconsistencies and fluctuations, especially when starting out, can cause deliverability issues. A predictable sending volume is crucial for maintaining a good sender reputation, and large fluctuations can trigger spam filters. Sudden spikes can be seen as signs of compromised accounts. Gradual and controlled volume increases, especially during IP warming, are important.

Key opinions

  • Volume Indirect Impact: Volume itself doesn't directly affect reputation; negative interactions drive poor reputation.
  • Fluctuation Issues: Fluctuations in email volume can cause problems, especially when beginning.
  • Predictable Volume: Consistently sending email at a predictable volume is a cornerstone of a good sender reputation.
  • Spike Interpretation: Sudden spikes in volume can be interpreted as a sign of compromised accounts.

Key considerations

  • Monitor Fluctuations: Monitor email sending for fluctuations, especially early on.
  • Gradual Increases: Implement gradual and controlled volume increases, particularly during IP warming.
  • Focus on Engagement: Prioritize sending wanted emails to encourage positive engagement.
  • Maintain Predictability: Aim to send at predictable volumes to help maintain your sender reputation.
Expert view

Expert from Email Geeks explains that volume doesn’t directly affect reputation or deliverability. Poor reputation develops because people don’t like the emails and interact with them negatively, signaling to machine learning filters that the mail is unwanted.

June 2023 - Email Geeks
Expert view

Expert from Email Geeks shares notes from 4 hours of talks on reputation, providing a link to a Google document that contains the call from last night and links back to the previous 3 calls. Calls 1 and 2 covered theory, while 3 and 4 focused on monitoring and development.

January 2024 - Email Geeks
Expert view

Expert from Email Geeks mentions that fluctuations in email volume can cause problems, especially when you’re initially starting out.

February 2024 - Email Geeks
Expert view

Expert from Word to the Wise, Laura Atkins, explains that a sudden spike in volume can be interpreted as a sign of a compromised account or bot activity, leading to filtering or blocking. She emphasizes the importance of gradual and controlled volume increases, especially during IP warming.

January 2023 - Word to the Wise
Expert view

Expert from Spamresource explains that consistently sending email at a predictable volume is a cornerstone of establishing and maintaining a good sender reputation. Large fluctuations in volume can trigger spam filters and negatively impact deliverability.

April 2023 - Spamresource

What the documentation says
4Technical articles

Email sending best practices emphasize the importance of gradual volume increases to establish a positive sender reputation. Sudden volume increases can trigger spam filters and damage reputation, especially when combined with high spam complaint rates. Incremental increases during IP warming are crucial for demonstrating consistent and legitimate email practices to ISPs.

Key findings

  • Spam Rate Sensitivity: Low spam rates are crucial, especially with high email volume, as even small percentages can damage reputation.
  • Sudden Increase Risk: Sudden increases in email volume can trigger spam filters.
  • IP Warming Importance: Gradually increasing email volume during IP address warming helps establish a positive sender reputation.
  • Incremental Increase Advice: RFC 5321 advises against sudden large increases, recommending incremental increases.

Key considerations

  • Monitor Spam Rates: Continuously monitor and minimize spam complaint rates.
  • Gradual Volume Adjustment: Avoid sudden spikes in sending volume and opt for gradual increases.
  • Implement IP Warming: Follow IP warming best practices when setting up new sending infrastructure.
  • Adhere to RFC Guidance: Follow the recommendations outlined in RFC 5321 regarding email sending volumes.
Technical article

Documentation from Google Postmaster Tools shares that keeping spam rates low is crucial, especially with high email volume. Even a small percentage of spam complaints can significantly damage sender reputation when sending a large number of emails.

August 2023 - Google Postmaster Tools
Technical article

Documentation from Microsoft responds that sudden increases in email volume can trigger spam filters. Gradual increases are recommended to maintain a positive sender reputation.

October 2024 - Microsoft
Technical article

Documentation from SparkPost explains the importance of gradually increasing email volume during IP address warming. This helps establish a positive sending reputation with ISPs by demonstrating consistent and legitimate email practices.

January 2025 - SparkPost
Technical article

Documentation from RFC Editor explains that RFC 5321 advises that message senders should avoid sudden large increases to email sending volume, and should incrementally increase email sending volume to build a solid sender reputation.

September 2024 - RFC Editor