Summary
HTML coding and content, while less impactful than IP/domain reputation, significantly influence email deliverability. Key issues include malformed HTML, non-FQDN URLs, hidden text, URL shorteners, and templates resembling spam, all of which can trigger spam filters. Clean, semantic HTML, inline CSS, optimized images with alt text, and accessible design are vital. Emojis are generally safe if used sparingly and tested across clients; avoid overuse and ensure relevance to the target audience. Using a single-column layout, including a preheader, and avoiding JavaScript, Flash, and embedded forms can further enhance deliverability. Regular maintenance to fix broken HTML is also recommended.
Key findings
- HTML Structure: Clean, valid, and semantic HTML improves deliverability and avoids spam triggers.
- Content Reputation: Reputation of content, especially URL hostnames and template origin, plays a significant role in inbox placement.
- Emoji Usage: Emojis are generally safe but require cautious and relevant usage to avoid spam flags and rendering issues.
- Image Optimization: Optimized images with alt text are essential for deliverability and accessibility.
- Technical Elements: Avoiding JavaScript, Flash, embedded forms, and URL shorteners improves deliverability.
- CSS Styling: Inline CSS ensures consistent rendering across email clients.
- IP/Domain Reputation: IP and domain reputation remain crucial factors for email deliverability.
Key considerations
- Accessibility: Ensure emails are accessible to users with disabilities to avoid deliverability issues.
- Regular Testing: Test emails across different clients and devices to ensure correct rendering and identify potential issues.
- Target Audience: Consider your target audience when using emojis; ensure they are receptive to them.
- Layout Simplicity: Opt for simpler, single-column layouts for better compatibility across email clients.
- Proactive Maintenance: Regularly check and fix malformed HTML to improve sender reputation.
- Content Legitimacy: Ensure HTML content resembles legitimate emails, not spam or phishing attempts.
- Preheader Text: Utilize preheader text strategically to further engage subscribers.
What email marketers say
13 marketer opinions
HTML coding significantly impacts email deliverability. Factors include using clean, valid HTML, avoiding broken tags or excessive code that can trigger spam filters, and ensuring mobile responsiveness. Templates copied from spam sources can also negatively affect deliverability due to fuzzy checksum filters. Emojis, while potentially increasing open rates, should be used sparingly and tested across different email clients to avoid rendering issues. The reputation of the content, image optimization, and the use of alt text are also crucial for maintaining a positive sender reputation and avoiding spam filters.
Key opinions
- HTML Coding Quality: Clean, valid HTML is essential to avoid triggering spam filters.
- Template Origin: Using templates associated with spam can negatively impact deliverability.
- Emoji Usage: Emojis can increase open rates but require careful usage to prevent spam flags and rendering issues.
- Image Optimization: Optimized images with alt text are important for deliverability.
- CSS Styling: Inline CSS is recommended for reliable rendering across email clients.
- Layout Simplicity: Simpler, single-column layouts improve deliverability.
- Preheader Importance: Utilizing a well-crafted preheader text optimizes email engagement.
Key considerations
- Content Relevance: Ensure emojis and HTML elements are relevant to the target audience and email content.
- Mobile Responsiveness: Design emails that are mobile-responsive and render correctly on various devices.
- Testing Across Clients: Test emails across different email clients and devices to ensure correct rendering.
- Spam Trigger Words: Avoid using elements or words that are commonly associated with spam.
- A/B Testing: Conduct A/B testing with and without emojis to optimize email performance.
- Code Maintenance: Regularly check and fix malformed HTML to improve sender reputation.
Marketer view
Email marketer from MailerLite suggests using a preheader. If you do not add a preheader, the email client will automatically pull text from the body of your email. Use this space wisely to further engage subscribers with a message that supports your subject line.
21 Feb 2024 - MailerLite
Marketer view
Email marketer from Email on Acid shares to consider how emojis render across different email clients. Some email clients may not support certain emojis, which can result in them appearing as boxes or other unexpected characters. Test your emails to ensure that emojis display correctly for your subscribers.
15 Jul 2024 - Email on Acid
What the experts say
5 expert opinions
HTML coding and content quality impact email deliverability, though IP/Domain reputation is typically more crucial. Specific HTML issues, like malformed code, non-FQDN URLs, URL masking, hidden text, and URL shorteners, can be stumbling blocks. Content reputation, especially URL hostnames, also matters. While emojis are generally safe, large images or numerous images can trigger spam filters. Regular maintenance, clean code, and image optimization are important.
Key opinions
- IP/Domain Reputation: IP and Domain reputation are primary factors for email deliverability.
- HTML Coding Issues: Malformed HTML, non-FQDN URLs, URL masking, hidden text, and URL shorteners negatively impact deliverability.
- Content Reputation: Content reputation, including URL hostnames, influences inbox placement.
- Image Size: Large or numerous images can trigger spam filters.
- Emoji Impact: Emojis, generally, do not negatively affect deliverability.
Key considerations
- Code Quality: Regularly maintain and fix malformed HTML code.
- Image Optimization: Optimize images for web use to reduce file size.
- URL Structure: Use Fully Qualified Domain Name (FQDN) URLs and avoid URL masking.
- Content Legitimacy: Ensure HTML content resembles legitimate emails, not spam or phishing attempts.
- Proactive Monitoring: Monitor for image-related blocks and adjust image usage accordingly.
Expert view
Expert from Email Geeks answers that emojis won't be a problem for deliverability.
10 Aug 2024 - Email Geeks
Expert view
Expert from Email Geeks shares that content plays a less important role in most delivery decisions and reputation of the IP/Domain are far more important. However, he lists stumbling blocks such as: URLs that are not FQDN, URLs that mask other URLs, hidden text / hash busters, URL shortners, and frequently re-used content that is finger printed by services like Cloudmark.
2 Aug 2021 - Email Geeks
What the documentation says
4 technical articles
Email deliverability is affected by HTML coding practices. Valid, clean HTML and semantic code are preferred to avoid triggering spam filters. It's important to keep code light, optimize images with alt text, use inline CSS and web-safe fonts. Accessibility for users with disabilities is crucial. Exercise caution with emojis, as excessive use can lead to spam flags. Avoid JavaScript, Flash, and embedded forms to maintain a clean and trusted email.
Key findings
- Valid HTML: Using valid and well-formatted HTML is important to prevent triggering spam filters.
- Code Optimization: Keeping code light and optimizing images with alt text improves deliverability.
- Accessibility: Ensuring email accessibility is key to avoid deliverability issues.
- Emoji Caution: While useful, excessive use of emojis can increase the risk of being marked as spam.
- Restricted Elements: Avoid using JavaScript, Flash, and embedded forms in HTML emails.
Key considerations
- Semantic Code: Prioritize semantic HTML to ensure clear and structured emails.
- Inline CSS: Use inline CSS for consistent styling across different email clients.
- Testing: Always test emails to ensure optimal performance and rendering across devices.
- Content Balance: Strike a balance in emoji usage to enhance without appearing spammy.
- Simplified Code: Opt for simple HTML code structures to ensure better compatibility.
Technical article
Documentation from Microsoft explains that HTML emails with excessive use of JavaScript, Flash, and embedded forms are more likely to be flagged as spam. Keep your HTML code simple and avoid using elements that are commonly associated with spam.
24 Jun 2021 - Microsoft
Technical article
Documentation from Mailjet explains to avoid using too much HTML, use inline CSS, optimize images and use alt text, use web-safe fonts and test, test, test.
1 Dec 2021 - Mailjet
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