Summary
Despite having a technically correct email setup (SPF, DKIM, DMARC), emails can still land in Gmail spam folders due to various interconnected factors that influence sender reputation and engagement. These include content quality resembling spam, image hosting practices, compliance with RFC 8058 for one-click unsubscribe, the use of multiple ESPs in a suspicious manner, sender reputation (including IP warming, shared IPs, and spam complaints), list hygiene, user engagement (opens and clicks), and the complex, ever-evolving algorithms used by mailbox providers. Proactive monitoring, continuous optimization, and adaptation to evolving best practices are critical for maintaining high deliverability.
Key findings
- Holistic Spam Evaluation: Gmail’s spam filters consider many signals beyond technical configurations, including content, sender reputation, and user engagement.
- Content is King: Email content resembling spam, using spam trigger words, or having misleading subject lines negatively impacts deliverability.
- Sender Reputation's Impact: Sender reputation, influenced by IP warming, shared IPs, spam complaints, and domain age, is a major factor in deliverability.
- Engagement Matters: Low engagement rates signal to Gmail that emails are unwanted.
- List Hygiene is Critical: Maintaining a clean email list and minimizing spam complaints are essential for a good sending reputation.
- Algorithms Evolve: Mailbox providers constantly update spam filtering algorithms, necessitating continuous monitoring and adaptation.
- Compliance Requirements: Adherence to email standards like RFC 8058 one-click unsubscribe is critical.
Key considerations
- Optimize Content: Refine email content to avoid spam triggers, and focus on providing value to recipients.
- Manage Reputation: Implement IP warming strategies for new domains/IPs and monitor sender reputation metrics.
- Engage Subscribers: Send relevant content, segment your audience, and prune inactive subscribers.
- Implement RFC 8058: Implement RFC 8058 one-click unsubscribe to improve deliverability.
- Analyze Sending Practices: Review image hosting configurations and avoid suspicious use of multiple ESPs.
- Continuous Monitoring: Monitor deliverability metrics and adapt strategies based on performance and algorithm changes.
- Authentication Check: Ensure correct set up of SPF, DKIM and DMARC protocols.
What email marketers say
11 marketer opinions
Even with technically correct email setups (SPF, DKIM, DMARC), emails can still land in Gmail spam folders due to a variety of factors. These include sender reputation (influenced by IP warming, shared IPs, spam complaints), content triggers (spam words, capitalization), lack of RFC 8058 one-click unsubscribe, poor engagement rates, image hosting issues, and email list hygiene. Continuous monitoring, optimization, and adaptation to Gmail's algorithm changes are essential.
Key opinions
- Authentication: Proper setup of SPF, DKIM, and DMARC is essential but not always sufficient. Monitor regularly.
- Sender Reputation: Sender reputation is critical. New domains/IPs require warming. Shared IPs can negatively impact deliverability.
- Content Matters: Content triggers, misleading subject lines, and excessive capitalization can cause spam filtering.
- Engagement is Key: Low engagement (opens/clicks) signals unwanted email to Gmail.
- List Hygiene: Maintaining a clean email list and minimizing spam complaints are critical for a good sending reputation.
Key considerations
- RFC 8058: Ensure compliance with RFC 8058 one-click unsubscribe to avoid deliverability issues.
- Image Hosting: Consolidate image hosting and avoid using multiple domains to reduce suspicion.
- Feedback Loops: Enroll in feedback loops (FBLs) to manage spam complaints effectively.
- A/B Testing: Continuously A/B test subject lines, sender names, and content to optimize engagement.
- Monitor Metrics: Regularly monitor key metrics (spam complaints, engagement) and adapt your strategy based on performance.
Marketer view
Email marketer from GMass shares that low engagement rates (opens, clicks) can signal to Gmail that your emails are unwanted. Focus on sending relevant content to engaged subscribers and pruning inactive users from your list to improve deliverability.
7 Feb 2024 - GMass
Marketer view
Email marketer from Reddit shares that even if everything seems technically correct, the sender's reputation plays a crucial role. If your domain or IP address is new or has a history of sending spam, Gmail will likely filter your emails. Warming up your IP and domain gradually is vital.
24 Feb 2022 - Reddit
What the experts say
8 expert opinions
Even with technically correct email setups, emails can still land in Gmail spam folders due to complex and evolving filtering algorithms. Factors contributing to this include content resembling spam, issues with shared image hosting domains, non-compliance with RFC8058 one-click unsubscribe, suspicious use of multiple ESPs, and the quality/relevance of email content. Continuous monitoring of metrics and adaptation to algorithm changes by mailbox providers is essential.
Key opinions
- Content Analysis: Gmail analyzes email content, and similarities to known spam can trigger filtering.
- Image Hosting: Using shared image hosting domains or a mix of different hosting providers can negatively impact deliverability.
- RFC 8058 Compliance: Lack of RFC8058 one-click unsubscribe can lead to emails being marked as spam, especially for new senders.
- Multiple ESP Usage: Using links from campaigns sent via one ESP while mailing through another can appear suspicious.
- Algorithm Evolution: Mailbox providers constantly update spam filtering algorithms, requiring ongoing adaptation.
Key considerations
- Content Optimization: Ensure email content is high quality and relevant to recipients to avoid spam triggers.
- Image Hosting Review: Review and potentially consolidate image hosting to avoid issues with shared or untrusted domains.
- Implement RFC 8058: Prioritize implementing RFC 8058 one-click unsubscribe for improved deliverability.
- ESP Consistency: Maintain consistency in sending practices across different ESPs to avoid suspicious behavior.
- Continuous Monitoring: Continuously monitor deliverability metrics and adapt your strategies to address algorithm changes.
Expert view
Expert from Email Geeks suggests that missing 8058 could be an immediate problem, especially without a history of sending wanted email, even if existing mail is being sent successfully elsewhere without it.
20 Jan 2024 - Email Geeks
Expert view
Expert from Word to the Wise answers that Gmail's spam filtering algorithms are complex and consider numerous factors beyond technical configurations. Content quality, relevance to the recipient, and engagement metrics (opens, clicks, replies) all play a significant role. Even seemingly minor issues can trigger spam filters.
9 Dec 2022 - Word to the Wise
What the documentation says
6 technical articles
Even with technically correct setups, emails can still land in spam due to various signals assessed by email providers. These signals include user reports, content analysis, sender reputation, and the absence of essential features like List-Unsubscribe headers. Maintaining a positive reputation requires IP/domain warming, proper DMARC implementation, and ongoing monitoring of authentication reports to prevent spoofing and unauthorized use.
Key findings
- Multifaceted Spam Filtering: Gmail and Outlook use diverse signals beyond technical setup to identify spam, including user reports and content analysis.
- User Feedback: Negative user feedback significantly impacts deliverability.
- List-Unsubscribe Header: The presence of a List-Unsubscribe header improves sender reputation and deliverability.
- Importance of DMARC: Implementing and monitoring DMARC is essential for preventing unauthorized use of your domain and improving deliverability.
- IP/Domain Warming: Warming up IP addresses and domains gradually is crucial for establishing a positive sending reputation, especially for new setups.
- DKIM Authentication: Using DKIM signatures authenticates your emails and prevents spoofing.
Key considerations
- Monitor User Feedback: Actively monitor user feedback and address any negative trends promptly.
- Implement DMARC: Implement a DMARC policy and regularly monitor DMARC reports.
- List Hygiene: Maintain a clean and engaged email list.
- Gradual IP Warming: Follow a gradual IP warming process for new IP addresses and domains.
- Proper DKIM Setup: Ensure proper DKIM signature implementation to authenticate your emails.
Technical article
Documentation from DKIM.org details that using DKIM signatures to authenticate emails is essential to prove that the message was sent and authorized by the owner of the domain. This helps prevent spoofing and improves deliverability.
8 Dec 2023 - DKIM.org
Technical article
Documentation from SparkPost details how warming up your IP address and domain gradually by increasing sending volume over time to establish a positive sending reputation. This is especially important for new IP addresses and domains.
8 Nov 2023 - SparkPost
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