Summary
The impact of erratic sending on deliverability with dedicated IPs, especially for consumer domains in the US, is complex and multi-faceted. A key theme is that consistent sending volume is crucial for building and maintaining a positive IP and sender reputation. While consumer ISPs in the US are generally good at separating email from shared IPs, erratic sending can still trigger spam filters, damage sender reputation, and lead to deliverability issues, particularly during IP warm-up and with Microsoft (Outlook/Hotmail). A gradual warm-up, consistent sending, segmentation, and monitoring are recommended. Some experts suggest that as long as all other factors are positive (clean cutover, good engagement), occasional fluctuations may not be significantly detrimental in the long term.
Key findings
- IP Reputation Damage: Erratic sending patterns can negatively impact IP and sender reputation, which are crucial for deliverability.
- Spam Trigger: Inconsistent sending volumes can trigger spam filters because they appear suspicious to ISPs.
- Warm-up Sensitivity: Erratic sending is particularly detrimental during the IP warm-up phase.
- Microsoft Impact: Deliverability to Microsoft domains (Outlook, Hotmail) is more susceptible to the effects of erratic sending.
- Segmentation Benefits: Segmentation can help manage sending frequency and maintain consistent volume.
- Consumer ISP Mitigation: While US consumer ISPs are better at separating emails, consistent sending is still essential for a positive sender reputation.
Key considerations
- Gradual Warm-up: Implement a gradual warm-up process for new dedicated IPs to establish a positive sending reputation.
- Consistent Sending: Strive for consistent daily or weekly sending schedules to keep reputation high.
- Segmentation Strategy: Segment your audience to maintain consistent sending volumes to each segment.
- Clean Cutover: Ensure a smooth transition when moving to dedicated IPs.
- Reputation Monitoring: Continuously monitor your sender reputation to identify and address potential deliverability issues promptly.
- Overall Health: While consistency is vital, maintaining good engagement and a clean cutover can mitigate some negative effects of occasional fluctuations.
What email marketers say
12 marketer opinions
Erratic sending patterns negatively impact email deliverability on dedicated IPs, particularly concerning consumer domains in the US. Consistent sending volume is crucial for building and maintaining a positive IP reputation, allowing ISPs to predict and trust email patterns. Fluctuations can trigger spam filters, damage sender reputation (especially with Microsoft deliverability), and lead to deliverability issues with major ISPs. While US consumer ISPs may be good at separating emails, erratic sending remains a concern. Gradual increases in volume, particularly during IP warm-up, are vital.
Key opinions
- IP Reputation: Erratic sending damages IP reputation, which is crucial for deliverability.
- Spam Filters: Inconsistent sending triggers spam filters due to suspicious patterns.
- Microsoft Deliverability: Erratic sending particularly affects deliverability with Microsoft (Outlook/Hotmail).
- Warm-up Impact: Erratic sending during IP warm-up negates the process and harms reputation.
- Segmentation: Consistent email volume is important so segmenting data is useful.
Key considerations
- Ramp-Up Gradualness: Ensure gradual increases in sending volume, especially during IP warm-up.
- Audience Location: While US ISPs are better at separating emails, sending patterns are still important.
- Sending Frequency: Maintain consistent daily or weekly sending schedules to keep reputation high.
- Clean Cutover: Ensure a clean cutover when moving to dedicated IPs.
- Segmentation Strategy: Segment your audience for consistent send times for each section.
Marketer view
Marketer from Email Geeks shares that while consumer ISPs in the US may be good at separating email from the same IP, this is not the case in many other countries, so it depends on the target audience, their location, and the local ISPs.
28 Apr 2025 - Email Geeks
Marketer view
Email marketer from Reddit shares that inconsistent sending volumes negatively impact deliverability because it disrupts the sender's reputation with ISPs. They suggest using segmentation to manage sending frequency.
7 Nov 2024 - Reddit
What the experts say
3 expert opinions
Experts offer differing perspectives on the impact of erratic sending on deliverability, particularly for consumer domains in the US. One viewpoint emphasizes that the effect of IP address reputation is minimal due to the ability of consumer ISPs to effectively separate email from the same IP. However, other experts stress that maintaining a consistent sending frequency is crucial for deliverability. Erratic sending, especially during IP warming, can negatively impact deliverability and raise suspicion among ISPs, potentially leading to filtering issues.
Key opinions
- ISP Separation: Consumer ISPs in the US are generally effective at separating email, minimizing the impact of IP reputation.
- Warming Impact: Erratic sending during IP warming can harm deliverability, even with dedicated IPs.
- Suspicious Patterns: Fluctuations in sending volume can trigger suspicion with ISPs and affect deliverability.
Key considerations
- Warming Consistency: Maintain a consistent sending pattern, especially when warming up a dedicated IP.
- Domain Focus: Consider the recipient domain, as consumer ISPs may handle traffic differently than business ISPs.
- Frequency Management: Strive to avoid large fluctuations in sending volume to maintain a positive sender reputation.
Expert view
Expert from Word to the Wise shares that maintaining a consistent sending frequency is crucial for deliverability. Fluctuations in volume can be seen as suspicious by ISPs and lead to filtering issues.
24 Feb 2022 - Word to the Wise
Expert view
Expert from Spam Resource, Laura Atkins, explains that erratic sending during IP warming can negatively impact deliverability. A consistent sending pattern is essential for establishing a good reputation with ISPs.
11 Nov 2022 - Spam Resource
What the documentation says
4 technical articles
Email service providers like SendGrid, SparkPost, Google, and Microsoft emphasize that consistent sending habits are critical for maintaining good deliverability on dedicated IPs. They caution against erratic volume changes, especially large spikes, as these are red flags for ISPs. Such fluctuations can lead to increased spam complaints and damage sender reputation. A gradual warm-up schedule, consistent sending, and adhering to best practices are recommended to ensure successful delivery, particularly to Gmail and Outlook.com users.
Key findings
- Warm-up Consistency: Consistent warm-up schedules are essential for new dedicated IPs; avoid large volume spikes early on.
- IP Reputation Building: Good IP reputation is built over time with consistent sending habits; erratic volume changes are a red flag.
- Spam Complaint Impact: Sudden volume spikes can lead to increased spam complaints and damage sender reputation.
- Reach: Consistent volume is crucial for deliverability to major consumer domains like Gmail and Outlook.com.
Key considerations
- Gradual Increase: Gradually increase sending volume over time, particularly during the warm-up phase.
- Best Practices Adherence: Adhere to email sending best practices to minimize deliverability issues.
- Monitor Reputation: Regularly monitor sender reputation to identify and address any potential problems.
- Low Spam Rate: Keep spam rate low for the best results with services like Gmail.
Technical article
Documentation from Microsoft advises that spikes in sending volume can impact your sender reputation negatively, particularly if not gradually increased. Maintaining consistent volume and adhering to best practices are important for reaching Outlook.com users.
31 Dec 2023 - Microsoft
Technical article
Documentation from SendGrid explains the importance of a consistent warmup schedule for new dedicated IPs, advising against large volume spikes early on to avoid deliverability issues. They recommend gradually increasing volume over time.
6 Sep 2021 - SendGrid
Do I need to warm up a new domain for a small email list?
How can I recover my Gmail IP reputation after a sudden drop and hitting spam traps?
How do bounces impact email deliverability and how can I minimize them?
How do email volume and volume fluctuations affect deliverability and sender reputation?
How do ESPs manage IP pools and how does it affect deliverability?
How do I warm up a new IP address for transactional emails?
