Can an email template trigger spam filters and cause deliverability issues?

Summary

Email templates significantly impact deliverability. Factors such as content, design, and HTML structure play a crucial role in whether an email reaches the inbox or is flagged as spam. Poorly designed templates with excessive images, spam trigger words, broken HTML, or high image-to-text ratios can trigger spam filters. Clean, well-coded templates, optimized images, and a balanced approach are essential. Other considerations include variations in rendering across email clients, sender reputation, and the accuracy of spam testing tools, plus seasonal factors affect open rates.

Key findings

  • Template's Influence: Email content, design, and HTML structure significantly influence deliverability.
  • Spam Triggers: Poorly designed templates, spam trigger words, broken HTML, and high image-to-text ratios can trigger spam filters.
  • Code Quality Matters: Bloated or messy HTML code can lead to emails being flagged as spam.
  • Image Balance: Using too many images and not enough text can cause emails to land in the spam folder.
  • Rendering: Variations in email rendering across different clients can inadvertently trigger spam filters.
  • Reputation Impact: Poor template design can damage sender reputation and cause deliverability issues.
  • Tool reliability: The accuracy and maintenance of probe accounts used by GlockApps and similar inbox testing tools is questionable.
  • Seasonal Impact: Lower email open rates during Christmas/New Year might be because people are busy with family and not checking their email.
  • Promotion Tab: Lower open rates are typical for emails landing in the promotions tab compared to the inbox

Key considerations

  • Clean Code: Ensure clean and well-structured HTML code, using inline CSS.
  • Content Balance: Maintain a healthy balance of images and text, providing alt tags for images and contextual text.
  • Spam Avoidance: Avoid using spam trigger words in email content and subject lines.
  • Follow Best Practices: Adhere to email best practices to improve deliverability and avoid spam filters.
  • Cross-Client Testing: Test email templates across different email clients to ensure consistent rendering.
  • Reputation Management: Monitor and maintain sender reputation through responsible email practices.
  • Evaluate Testing Tools: Evaluate and use testing tools with caution, understanding their limitations.
  • Track Open Rates: Track open rates to gauge actual deliverability
  • Check Template Elements: Use tools to check the basic elements of the template

What email marketers say
6Marketer opinions

Email templates significantly impact deliverability. Poorly designed templates, with issues like excessive images, messy code, spam trigger words, or bad HTML, can trigger spam filters. Clean code, balanced content, optimized images, and adherence to email best practices are crucial for inbox placement.

Key opinions

  • Template Design: The design, code, and content of an email template significantly influence its deliverability.
  • Poor Optimization: Poorly optimized templates can trigger spam filters due to spam trigger words, broken HTML, or high image-to-text ratios.
  • HTML Code: Bloated or messy HTML code can lead to emails being flagged as spam.
  • Image-to-Text Ratio: Using too many images and not enough text can cause emails to land in the spam folder.

Key considerations

  • Clean Code: Ensure your HTML code is clean and well-structured, using inline CSS.
  • Content Balance: Balance the use of images and text, providing alt tags for images and contextual text.
  • Spam Triggers: Avoid using spam trigger words in your email content and subject lines.
  • Email Best Practices: Follow email best practices to improve deliverability and avoid spam filters.
  • Template Design: Ensure your email is optimised for content, design and HTML mark-up.
Marketer view

Email marketer from HubSpot explains that a poorly optimized email template can trigger spam filters due to factors like excessive use of spam trigger words, broken HTML, or a high image-to-text ratio. Keeping templates clean and balanced is crucial.

May 2021 - HubSpot
Marketer view

Email marketer from MailerLite responds that a poorly coded or designed email template can hurt deliverability. Using clean HTML, optimized images, and avoiding spam trigger words are essential for inbox placement.

October 2023 - MailerLite
Marketer view

Email marketer from StackOverflow shares that using too many images and not enough text in your template will almost certainly cause it to go to the spam folder. Use Alt tags and provide context in text.

July 2024 - StackOverflow
Marketer view

Email marketer from Reddit shares that email templates with bloated or messy HTML code are often flagged as spam. Keeping the code clean, using inline CSS, and optimizing images can help improve deliverability.

August 2021 - Reddit
Marketer view

Email marketer from ActiveCampaign shares that the content, design and HTML mark-up of your email can lead to issues with deliverability. Following best practice can help with this.

March 2023 - ActiveCampaign
Marketer view

Email marketer from EmailOctopus shares that an email template’s design, code, and content significantly influence whether it lands in the inbox or spam folder. A clean, well-coded template is crucial.

March 2022 - EmailOctopus

What the experts say
9Expert opinions

Email templates, particularly their content and code, can significantly impact deliverability. Poorly designed templates, variations in rendering across email clients, and content choices can trigger spam filters. High open rates might indicate deliverability is better than spam tests suggest. Low open rates could be due to placement in the promotions tab or seasonal factors. The reliability of spam testing tools like GlockApps is also questioned. A damaged sender reputation can result from poor template design.

Key opinions

  • Template Impact: Email content and templates significantly influence deliverability and can trigger spam filters.
  • Open Rate Indicator: High open rates may suggest deliverability is better than indicated by spam testing tools.
  • Promotions Tab: Lower open rates are typical for emails landing in the promotions tab.
  • Testing Tool Accuracy: The accuracy and reliability of spam testing tools like GlockApps are questionable.
  • Rendering Variations: Variations in email rendering across different clients can inadvertently trigger spam filters.
  • Reputation Impact: Poorly designed email templates can damage sender reputation and impact deliverability.

Key considerations

  • Template Design: Pay attention to email template design and content choices to avoid triggering spam filters.
  • Monitor Open Rates: Monitor open rates to gauge actual deliverability, and consider seasonal factors.
  • Testing Tool Limitations: Be aware of the limitations and potential inaccuracies of spam testing tools.
  • Rendering Consistency: Consider how your email template renders across different email clients.
  • Check Basic Elements: Use tools to check the basic elements of the template.
Expert view

Expert from Email Geeks suggests that high open rates indicate there might not be a catastrophic deliverability issue despite what GlockApps suggests, assuming the opens mean the email reached the inbox.

May 2024 - Email Geeks
Expert view

Expert from Email Geeks questions the accuracy and maintenance of probe accounts used by GlockApps and similar inbox testing tools.

February 2024 - Email Geeks
Expert view

Expert from Email Geeks agrees with Laura that GlockApps doesn't have any special sauce and questions the probe accounts they use.

December 2021 - Email Geeks
Expert view

Expert from SpamResource explains that variations in how an email template renders across different email clients can inadvertently trigger spam filters. This is because the altered rendering might introduce code or formatting that resembles spam.

October 2021 - SpamResource
Expert view

Expert from Email Geeks concludes that there may not actually be a spam issue present.

July 2022 - Email Geeks
Expert view

Expert from Word to the Wise responds that a poorly designed email can damage your sender reputation, and cause deliverability issues. Use tools to check the basic elements of the template.

August 2022 - Word to the Wise
Expert view

Expert from Email Geeks states that content can indeed trigger spam filters, and the email template significantly influences the distinctive features of the content.

November 2024 - Email Geeks
Expert view

Expert from Email Geeks shares that lower open rates are typical for emails landing in the promotions tab compared to the inbox. A 28% open rate might be normal for the promotions tab.

February 2022 - Email Geeks
Expert view

Expert from Email Geeks suggests that lower email open rates during Christmas/New Year might be because people are busy with family and not checking their email.

June 2021 - Email Geeks

What the documentation says
3Technical articles

Email templates significantly affect deliverability. Poorly designed templates, excessive images, improper HTML, spam trigger keywords, and a high image-to-text ratio increase the likelihood of being flagged as spam. Spam filters analyze content, formatting, and sender reputation to identify suspicious elements.

Key findings

  • Content Impact: Email content, structure, and design significantly impact deliverability.
  • Spam Analysis: Spam filters analyze content for suspicious elements.
  • Poor Design Risks: Poorly designed templates with excessive images or improper HTML are more likely to be flagged as spam.
  • Trigger Keywords: Specific keywords commonly associated with spam can trigger filters.
  • Image-Text Ratio: A high image-to-text ratio increases the chances of emails being marked as spam.
  • Code Quality: Broken or poorly coded HTML in templates can negatively affect deliverability.
  • Reputation Matters: Sender reputation is a factor in Google's spam filter evaluation.

Key considerations

  • Template Optimization: Optimize email templates to ensure clean design, proper HTML, and balanced content.
  • Keyword Awareness: Avoid using spam trigger keywords in email content.
  • Image Usage: Use images sparingly and maintain a healthy text-to-image ratio.
  • Code Validation: Validate HTML code to prevent errors that may trigger spam filters.
  • Sender Reputation: Maintain a positive sender reputation by following email best practices.
Technical article

Documentation from Google Workspace explains that Google's spam filters evaluate many aspects of an email, including content, formatting, and sender reputation. Using a poorly coded template, or one that contains elements commonly found in spam emails, can negatively affect deliverability.

November 2023 - Google
Technical article

Documentation from Mailjet explains that email content, including the template structure and design, significantly impacts deliverability. Spam filters analyze content for suspicious elements, and a poorly designed template with excessive use of images or improper HTML can increase the likelihood of being flagged as spam.

July 2024 - Mailjet
Technical article

Documentation from SendPulse shares that certain keywords commonly associated with spam can trigger filters. Also, a template with a high image-to-text ratio, or broken HTML code, can increase the chances of the email being marked as spam.

July 2023 - SendPulse