Why are my email newsletters going to the spam folder in Gmail?

Summary

Email newsletters frequently land in Gmail spam folders due to a complex interplay of factors related to authentication, sender reputation, engagement, content, and technical configurations. Gmail's filtering is highly personalized, heavily weighting user engagement signals. Poor authentication practices (missing or misconfigured SPF, DKIM, DMARC), low sender reputation (resulting from low engagement, high complaint rates, sending to inactive addresses, or sharing IPs with spammers), and being listed on blocklists are major culprits. Content-related problems such as spam trigger words, poor formatting, excessive images, and inaccessible design contribute to spam classification. Technical aspects like missing PTR records and the use of URL shorteners also play a role. Implementing feedback loops (FBLs) and making unsubscribing easy are vital for maintaining list hygiene and sender reputation. Proactive measures include regularly monitoring IP reputation, testing emails with spam checkers, and maintaining consistent sending patterns.

Key findings

  • Authentication is Key: Proper implementation of SPF, DKIM, and DMARC is crucial for establishing trust with email providers.
  • Reputation Matters: A positive sender reputation, built through consistent engagement and minimal complaints, is essential for inbox placement.
  • Engagement Drives Delivery: Gmail heavily relies on user engagement (opens, clicks, replies) to determine whether to deliver emails to the inbox or spam folder.
  • Content Can Trigger Spam Filters: Spam trigger words, poor formatting, excessive images, and inaccessible design can lead to spam classification.
  • Technical Setup is Critical: Missing PTR records, inadequate DMARC policies, and being on blocklists can negatively impact deliverability.
  • List Hygiene is Paramount: Regularly cleaning email lists and making unsubscribing easy helps maintain sender reputation.

Key considerations

  • Implement Strong Authentication: Ensure SPF, DKIM, and DMARC records are correctly configured.
  • Build a Positive Reputation: Focus on sending relevant, engaging content to build a strong sender reputation.
  • Segment and Target: Segment your email lists and tailor content to specific audience interests to boost engagement.
  • Optimize Email Content: Avoid spam trigger words, optimize email formatting, and use images sparingly.
  • Monitor Blocklists and IP Reputation: Regularly check blocklists and IP reputation using tools like Talos or Spamhaus.
  • Implement Feedback Loops: Use feedback loops to identify and remove subscribers who mark your emails as spam.
  • Make Unsubscribing Easy: Provide a clear and easy-to-find unsubscribe link in all emails.
  • Test Before Sending: Test your emails with spam checker tools before sending to identify and resolve potential issues.
  • Review Sending Frequency: Assess send frequency to ensure you're not overwhelming your subscribers.
  • Avoid URL Shorteners: Use full, direct links in your emails instead of URL shorteners when possible.
  • Consider a Dedicated IP: If sending high volumes of email, consider using a dedicated IP address to control your sending reputation.

What email marketers say
11Marketer opinions

Email newsletters often land in Gmail's spam folder due to a combination of factors. These include poor authentication practices (lack of SPF, DKIM, DMARC), low sender reputation stemming from low engagement, high complaint rates, sending to inactive or outdated email lists, and sharing IP addresses with spammers. Content-related issues such as spam trigger words, poor formatting, excessive images, and inaccessible design can also trigger spam filters. Furthermore, Gmail considers individual user engagement; unread emails may be marked as spam. Ensuring easy unsubscribe options and testing emails with spam checkers are proactive steps to improve deliverability.

Key opinions

  • Authentication: Lack of proper email authentication (SPF, DKIM, DMARC) is a primary reason for spam filtering.
  • Sender Reputation: Low sender reputation, caused by low engagement and high complaint rates, leads to spam placement.
  • List Hygiene: Sending emails to outdated or inactive lists damages sender reputation and increases spam likelihood.
  • Content Issues: Spam trigger words, poor formatting, and excessive images in email content can trigger spam filters.
  • Engagement: Low user engagement (unopened emails) contributes to Gmail filtering messages as spam.

Key considerations

  • Implement Authentication: Configure SPF, DKIM, and DMARC records to authenticate your email and improve deliverability.
  • Improve Engagement: Focus on sending relevant content to engaged subscribers to increase open and click rates.
  • Clean Your Lists: Regularly remove inactive or outdated email addresses from your mailing lists.
  • Optimize Content: Avoid spam trigger words, optimize email formatting, and use images sparingly.
  • Test Before Sending: Use spam checker tools to identify and resolve potential issues before sending your newsletters.
  • Dedicated IP: Consider switching to a dedicated IP address to manage your sender reputation effectively.
  • Easy Unsubscribe: Ensure a clear and easy-to-find unsubscribe link in all emails.
Marketer view

Email marketer from Constant Contact shares that failing to properly authenticate your email with SPF, DKIM, and DMARC records can cause receiving servers to distrust your messages and send them to spam.

April 2022 - Constant Contact
Marketer view

Email marketer from Litmus shares that designing emails with accessibility in mind can help your emails land in the inbox. If your email isn't accessible, it may be flagged as spam.

March 2025 - Litmus
Marketer view

Email marketer from Email on Acid shares that testing your emails with spam filter checkers before sending can help you identify and fix potential issues that might cause your emails to be flagged as spam.

December 2022 - Email on Acid
Marketer view

Email marketer from Neil Patel's Blog explains that using spam trigger words, having poor email formatting, and sending emails to unengaged subscribers are common reasons for emails landing in the spam folder.

February 2022 - Neil Patel's Blog
Marketer view

Marketer from Email Geeks explains that after a certain number of unopened/unread pieces of email languish in your inbox, Gmail (and other providers) *may* put it in the spam folder, because they figure you don't want it. On their end their 'mission' is to deliver only email that you want to your inbox.

April 2022 - Email Geeks
Marketer view

Marketer from Email Geeks responds that it's a known thing in their circles and Google has become much tighter about authentication. Email marketing and newsletters that have authentication set up correctly are in the minority.

February 2022 - Email Geeks
Marketer view

Email marketer from Sendinblue explains that a poor sender reputation, often due to low engagement or high complaint rates, can significantly impact deliverability and cause emails to go to spam.

February 2023 - Sendinblue
Marketer view

Email marketer from Mailjet shares that using excessive images, large attachments, or poorly coded HTML can trigger spam filters based on content analysis.

July 2021 - Mailjet
Marketer view

Email marketer from HubSpot explains that sending emails to outdated or inactive email addresses increases bounce rates, which damages your sender reputation and leads to emails being marked as spam.

March 2022 - HubSpot
Marketer view

Email marketer from Reddit explains that using a shared IP address with a poor reputation (due to other users' spam practices) can negatively impact your email deliverability. Switching to a dedicated IP can help.

January 2023 - Reddit
Marketer view

Email marketer from Campaign Monitor explains that making it easy for recipients to unsubscribe reduces the likelihood they'll mark your emails as spam. Include a clear and accessible unsubscribe link in every email.

August 2021 - Campaign Monitor

What the experts say
5Expert opinions

Email newsletters are being filtered into Gmail's spam folder due to a combination of factors related to IP reputation, sending consistency, engagement metrics, and the use of URL shorteners. Gmail's filtering is highly individualized and prioritizes user engagement signals such as opens, clicks, and replies. A poor IP reputation, often due to being listed on blocklists, can significantly affect deliverability. Inconsistent sending patterns and volume spikes also trigger spam filters. The use of URL shorteners, particularly those with a history of abuse, can negatively impact deliverability as well.

Key opinions

  • Individualized Filtering: Gmail's filtering is unique to each user and heavily influenced by engagement.
  • IP Reputation: A low IP address reputation can result in emails being sent to spam.
  • Consistency: Inconsistent sending patterns and volume spikes raise red flags with spam filters.
  • Engagement Metrics: Gmail uses opens, clicks, and replies to determine inbox placement.
  • URL Shorteners: The use of URL shorteners can negatively impact deliverability.

Key considerations

  • Monitor IP Reputation: Regularly check your IP address reputation using tools like Talos or Spamhaus.
  • Maintain Consistency: Establish a consistent sending volume and pattern to build a positive reputation.
  • Boost Engagement: Improve email content and targeting to increase opens, clicks, and replies.
  • Avoid URL Shorteners: Use full, direct links in your emails instead of URL shorteners.
Expert view

Expert from Word to the Wise shares that consistency in sending volume and patterns helps build a good reputation with ISPs. Sudden spikes in email volume can trigger spam filters.

April 2024 - Word to the Wise
Expert view

Expert from Spam Resource explains that a low IP address reputation can cause emails to go to spam. You can check the reputation of your IP address at Talos or Spamhaus.

January 2023 - Spam Resource
Expert view

Expert from Email Geeks shares that Gmail filtering is very individualistic and heavily weights engagement.

May 2023 - Email Geeks
Expert view

Expert from Word to the Wise shares that using URL shorteners, especially those that are commonly abused for spam, can negatively impact deliverability. Using full, direct links is preferred.

August 2023 - Word to the Wise
Expert view

Expert from Spam Resource explains that Gmail uses engagement metrics like opens, clicks, and replies to decide whether to deliver emails to the inbox or spam folder. Low engagement leads to spam filtering.

July 2024 - Spam Resource

What the documentation says
5Technical articles

Email newsletters often end up in Gmail's spam folder due to several technical and user-driven reasons. User-reported spam flags significantly impact future deliverability. Being listed on blocklists due to spam complaints prevents inbox placement. A missing or invalid reverse DNS (PTR) record can cause servers to flag messages as spam. Inadequate DMARC policies (specifically 'none') fail to provide authentication guidance, increasing spam likelihood. Implementing feedback loops (FBLs) is essential for identifying and removing subscribers who mark emails as spam, improving sender reputation.

Key findings

  • User Spam Flags: User-reported spam flags directly impact future email deliverability.
  • Blocklisting: Being on a blocklist prevents emails from reaching the inbox.
  • Missing PTR Record: Absence of a valid reverse DNS record can lead to spam filtering.
  • Inadequate DMARC: DMARC policies set to 'none' increase the likelihood of spam classification.
  • Feedback Loops: Lack of feedback loop implementation hinders identification and removal of users reporting spam.

Key considerations

  • Minimize Spam Reports: Ensure relevant and desired content to reduce user-reported spam flags.
  • Monitor Blocklists: Regularly check and take action to be removed from any blocklists.
  • Implement PTR Record: Ensure a valid reverse DNS record is properly configured.
  • Configure DMARC: Set DMARC policy to 'quarantine' or 'reject' to enhance authentication.
  • Implement FBLs: Implement feedback loops to identify and remove users reporting spam to improve sender reputation.
Technical article

Documentation from RFC-Editor explains that the absence of a valid reverse DNS record (PTR record) can cause some email servers to flag your messages as potentially spam.

January 2022 - RFC-Editor
Technical article

Documentation from Microsoft Support shares that being on a block list, often due to spam complaints, can prevent your email from reaching inboxes. It is crucial to monitor block lists and take steps to be removed.

December 2024 - Microsoft Support
Technical article

Documentation from Google Support explains that Gmail users can mark messages as spam, and if a significant number of users do this, future emails from that sender are more likely to be filtered as spam.

September 2022 - Google Support
Technical article

Documentation from DMARC.org explains that having a DMARC policy set to 'none' provides no instruction to receiving servers on how to handle unauthenticated emails, which can make your emails more likely to be flagged as spam. Set to quarantine or reject to improve deliverability.

May 2024 - DMARC.org
Technical article

Documentation from SparkPost explains that implementing feedback loops (FBLs) allows you to identify and remove subscribers who mark your emails as spam, helping you maintain a clean list and improve your sender reputation.

February 2023 - SparkPost