Why is it important to use HTTPS for links and images in email marketing?

Key findings

• Future-proofing: While HTTP links might still work for a short period, the trend points towards a future where HTTPS will be a mandatory standard for proper display and functionality.
• Browser warnings: Some browsers and email clients (like Comcast's client with Chrome) may display security warnings or even block content that uses HTTP links or images within an otherwise HTTPS-secured environment.
• HSTS impact: HTTP Strict Transport Security (HSTS) can cause HTTP links that redirect to HTTPS sites to fail on subsequent clicks unless the browser cache is cleared, leading to a frustrating user experience.
• Mixed content issues: Mixing HTTP and HTTPS content within an email can lead to display errors, especially in the ''view online'' version of an email, affecting overall rendering.
• Google's preference: Google actively promotes HTTPS for better search rankings and a more secure web, suggesting a likely bias towards HTTPS content in Gmail's filtering and display mechanisms, as highlighted by articles from Taxi for Email.

Key considerations

• User trust: Secure links reassure recipients that their data is protected, potentially leading to higher click-through rates and better engagement.
• Deliverability impact: While not a primary deliverability factor in all cases, using secure links contributes to overall sender trustworthiness and can help avoid flags from spam filters. Learn more about how secure HTTPS links improve deliverability.
• Image display: Images hosted on HTTP may not load in email clients that enforce HTTPS, leading to broken visuals and a poor recipient experience. Gmail proxies images, mitigating this specific issue for Gmail users, but it remains a concern for others.
• Brand reputation: Consistently using HTTPS across all email elements demonstrates a commitment to security and professionalism, safeguarding your brand's reputation. This is tied to your sender reputation.
• Transition planning: While not an emergency for deliverability, transitioning to HTTPS for all email assets is a beneficial improvement that should be scheduled and prioritized for optimal performance and future compatibility.

Key opinions

• Not an immediate deliverability killer: Many marketers find that HTTP links aren't a direct cause of emails landing in spam folders right now, but this could change.
• Future necessity: There's a strong belief that HTTPS will become essential for email content to display correctly in the near future, aligning with general web security trends.
• Rendering issues: Some marketers have observed that pages, particularly 'view online' versions, do not render correctly when there's a mix of HTTP and HTTPS content within an email.
• Chrome's strictness: Chrome browsers, when used with certain email clients, will block HTTP images entirely unless the image can also load over HTTPS and auto-upgrade.
• Trust and clicks: Secure, verified links are perceived as safer by recipients, which can lead to higher engagement rates, as noted by Rebrandly Blog.

Key considerations

• Prioritize now: While perhaps not urgent, updating to HTTPS for all email elements is a valuable improvement that should be planned and executed soon.
• Consistency: Ensure all links and images, including tracking links, consistently use HTTPS to avoid mixed content warnings and display issues.
• User experience: A seamless experience without broken images or warnings contributes to recipient satisfaction and engagement.
• Brand perception: Using secure links enhances the professional image of your brand. You can explore more on how HTTP links affect deliverability.
• Adapt to changes: Staying updated with browser and email client changes, particularly concerning mixed content, is crucial for email marketers.

Key opinions

• Security priority: Security experts emphasize that HTTPS protects data in transit, which is critical for all online interactions, including those initiated from emails.
• Anti-phishing measure: Using secure links helps prevent unauthorized use of your domain and protects against phishing attempts by cybercriminals who might try to impersonate your brand.
• Industry standard: The internet is moving towards HTTPS as a universal standard, and email marketing should align with this evolution to avoid being flagged as outdated or insecure.
• Implicit trust signals: While not always explicitly filtered for, the absence of HTTPS can serve as a subtle negative signal to mailbox providers and security systems, eroding sender trust over time.
• User experience degradation: Broken images or security warnings, even if only occasional, significantly degrade the recipient's experience, increasing the likelihood of unengagement and complaints.

Key considerations

• Comprehensive security: Implement HTTPS not just for your website, but for all hosted email assets and tracking links. This forms part of a broader email security strategy, including configuring SSL/TLS on sending domains.
• Avoid mixed content: Actively audit your email templates to ensure no HTTP links or images slip through, as mixed content can trigger warnings or blocking by email clients and browsers. Find out more about how Chrome blocking mixed content affects email deliverability.
• User perception: Recognize that recipients are increasingly aware of security indicators, and the presence of HTTPS instills confidence.
• Proactive approach: Implement HTTPS now to get ahead of future tightening of security policies by mailbox providers and web browsers.

Key findings

• Data encryption: HTTPS protects data transferred between a user and a website via encryption, which is necessary for sensitive information. This is a core function, as explained by Fortinet.
• Security mechanism: HSTS (HTTP Strict Transport Security) is a web security policy that enforces interactions with websites only via secure HTTPS connections, preventing downgrade attacks and ensuring consistent security.
• Anti-impersonation: Using SSL/TLS (which HTTPS relies upon) helps prevent unauthorized use of your domain and protects your brand from cybercriminals impersonating your email.
• Enhanced user perception: Documentation often implies that HTTPS links provide visual cues of security, reassuring users and encouraging trust.
• Deliverability contribution: Secure links contribute to overall deliverability by being less likely to be flagged by spam filters, improving inbox placement.

Key considerations

• Universal adoption: The mandate for HTTPS is now a pervasive standard across the web, making its implementation non-negotiable for any digital communication, including email.
• Preventing data interception: HTTPS encrypts the data (using SSL/TLS), making it unreadable to unauthorized parties, which is crucial for protecting user privacy and preventing malicious alterations of content.
• Brand integrity: Official recommendations suggest that using secure protocols is vital for maintaining brand credibility and trust in a security-conscious environment.
• Compliance: Adhering to HTTPS best practices helps email marketers comply with evolving internet security standards and browser policies.