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

Summary

Using HTTPS for links and images in email marketing is crucial for several reasons encompassing security, deliverability, user experience, and future compatibility. HTTPS ensures data encryption, protecting sensitive information and building user trust. Many email clients are implementing stricter security policies, potentially blocking or warning users about non-HTTPS content. HTTPS helps prevent man-in-the-middle attacks and ensures data integrity. It also resolves rendering issues, especially in 'view online' versions and dark mode, providing a more seamless experience across devices and applications. The use of HTTPS avoids mixed content warnings and potential blocking by browsers. While it doesn't directly impact website SEO, using HTTPS links indirectly improves brand perception. Issues such as HSTS and browser warnings further reinforce the need for HTTPS to ensure consistent functionality and security, making it a best practice for future-proofing email marketing strategies. Google's preference for HTTPS might also benefit deliverability, particularly to Gmail users. Moreover, HTTPS enables the use of HTTP/2, which can potentially improve website loading speed and overall user experience.

Key findings

  • Enhanced Security: HTTPS encrypts data, preventing interception and ensuring privacy, thus building user trust and safeguarding sensitive information.
  • Improved Deliverability: Email providers are increasingly likely to flag or block emails with HTTP links, making HTTPS essential for maintaining good deliverability and avoiding spam filters.
  • Better User Experience: HTTPS resolves rendering issues, especially in 'view online' versions and dark mode, and provides a more seamless experience across devices, avoiding mixed content warnings.
  • Future-Proofing: Adopting HTTPS is a proactive measure as browsers and email clients become stricter on security, ensuring consistent functionality and compatibility in the long run.
  • HSTS Prevention: Using HTTPS prevents the HTTP Strict Transport Security (HSTS) from causing HTTP links that redirect to HTTPS sites to fail until the browser cache is cleared.
  • Performance Improvement: HTTPS enables HTTP/2, potentially improving website loading speed and overall user experience if links point to secure websites.

Key considerations

  • Enforce HTTPS Everywhere: Ensure all links and images in your emails use HTTPS to provide a secure and reliable experience for recipients.
  • Test Across Platforms: Thoroughly test emails in various email clients and browsers, particularly when 'view online' versions are used, to avoid mixed content and rendering issues.
  • Update Existing Campaigns: Review and update existing email templates and campaigns to replace HTTP links with HTTPS equivalents.
  • Educate Your Audience: Inform your audience about the security benefits of HTTPS and the steps you're taking to protect their data to build trust and encourage engagement.
  • Check Image Rendering: Verify images render correctly, especially in dark mode email clients, which might have different default settings for displaying HTTP images.
  • Monitor Security Policies: Stay informed about evolving email client and browser security policies to ensure your emails remain compliant and functional.

What email marketers say
12Marketer opinions

Using HTTPS for links and images in email marketing is crucial for several reasons. It ensures data encryption, protecting sensitive information and building user trust. Many email clients are implementing stricter security policies, potentially blocking or warning users about non-HTTPS content. HTTPS helps prevent man-in-the-middle attacks and ensures data integrity. It also improves rendering, particularly in 'view online' versions and dark mode, while providing a more seamless experience across devices. While it does have a direct impact on website SEO, using HTTPS links indirectly improves brand perception. Additionally, issues like HSTS and browser warnings reinforce the need for HTTPS to ensure consistent functionality and security, making it a best practice for future-proofing email marketing strategies.

Key opinions

  • Security: HTTPS encrypts data, preventing interception and ensuring privacy, which enhances user trust and safeguards sensitive information.
  • Deliverability: Email providers are increasingly likely to flag or block emails with HTTP links, making HTTPS essential for maintaining good deliverability.
  • Rendering Issues: Mixing HTTP and HTTPS content can cause rendering problems in email clients, especially in 'view online' versions and dark mode, leading to broken images or warnings.
  • HSTS Complications: HTTP Strict Transport Security (HSTS) can cause issues where HTTP links redirecting to HTTPS sites will fail until cache is cleared.
  • Future Proofing: Adopting HTTPS is a proactive measure as browsers and email clients become stricter on security, ensuring consistent functionality in the long run.

Key considerations

  • Enforce HTTPS: Ensure all links and images in your emails use HTTPS to provide a secure and reliable experience for recipients.
  • Test Rendering: Thoroughly test emails in various email clients and browsers, particularly when 'view online' versions are used, to avoid mixed content rendering issues.
  • Update Links: Review and update existing email templates and campaigns to replace HTTP links with HTTPS equivalents.
  • Educate Users: Inform your audience about the security benefits of HTTPS and the steps you're taking to protect their data to build trust and encourage engagement.
  • Dark Mode Rendering: Ensure HTTPS is used when sending emails so users using dark mode email clients can view the images and they render correctly.
Marketer view

Email marketer from Email Geeks explains that images in emails must be HTTPS, or they may not load in some email clients like Comcast when accessed over HTTPS. Chrome may auto-upgrade HTTP images to HTTPS if available. Gmail uses a proxy so this is not an issue.

November 2022 - Email Geeks
Marketer view

Email marketer from Litmus Community responds that using HTTP images can lead to rendering issues in some email clients, especially when the email itself is viewed over HTTPS. This can result in broken images or security warnings.

March 2024 - Litmus Community
Marketer view

Email marketer from Sendinblue shares that while HTTPS directly impacts website SEO, using HTTPS links in emails can indirectly improve brand perception and trust, leading to better engagement metrics. Also, secure sites are often prioritized.

March 2022 - Sendinblue
Marketer view

Email marketer from Mailjet explains that using HTTPS ensures data encryption between the user's computer and the server, protecting sensitive information. It also helps improve email deliverability as some email providers may flag emails with HTTP links as suspicious.

September 2024 - Mailjet
Marketer view

Email marketer from Campaign Monitor explains that many email clients are moving towards stricter security policies. Some may block or warn users about emails containing non-HTTPS links and resources.

September 2022 - Campaign Monitor
Marketer view

Email marketer from Reddit responds that using HTTPS image links will ensure better image rendering and experience for users using dark mode email clients. Some clients will not display images that are not HTTPS enabled by default.

August 2024 - Reddit
Marketer view

Email marketer from Reddit shares that using HTTPS links enhances user trust. Seeing the secure padlock icon in their browser builds confidence and encourages interaction with the email's content.

May 2023 - Reddit
Marketer view

Email marketer from Stack Overflow mentions that Browsers and Email Clients show warnings for HTTP because it doesn't encrypt data. Without encryption, user data can be intercepted.

July 2023 - Stack Overflow
Marketer view

Email marketer from Email on Acid shares that adopting HTTPS for all email links and images is a future-proof strategy. As web standards evolve, browsers and email clients will likely become even more strict about enforcing HTTPS.

January 2023 - Email on Acid
Marketer view

Email marketer from Email Geeks shares issues can arise with page rendering in "view online" versions of emails when mixing HTTP and HTTPS content.

July 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks shares the HSTS (HTTP Strict Transport Security) can cause issues where HTTP links redirecting to HTTPS sites fail on consecutive attempts until the browser cache is cleared. HSTS forces browsers to use secure HTTPS connections.

March 2023 - Email Geeks
Marketer view

Email marketer from EmailVendorSelection responds that it is a best-practice approach to only use HTTPS. It provides a seamless experience across devices and applications.

August 2021 - EmailVendorSelection

What the experts say
3Expert opinions

Using HTTPS for links and images in email marketing is important for several reasons. Browsers are increasingly warning about non-HTTPS links, and eventually emails might not display correctly. Google favors HTTPS links, potentially improving email deliverability to Gmail users. More broadly, HTTPS builds user trust by ensuring a secure, encrypted connection, protecting sensitive information and preventing eavesdropping and man-in-the-middle attacks.

Key opinions

  • Browser Warnings: Browsers are beginning to display warnings for HTTP links, indicating a move towards requiring HTTPS for all web content.
  • Future Compatibility: Emails using only HTTP may eventually not display correctly in some clients.
  • Google Favoritism: Google favors HTTPS, which may give emails with HTTPS links an advantage, especially for Gmail users.
  • User Trust: HTTPS builds trust by encrypting the connection between the user and the server.
  • Security: HTTPS protects sensitive information by preventing eavesdropping and man-in-the-middle attacks.

Key considerations

  • Transition to HTTPS: Make a plan to transition all email links and images to HTTPS to ensure compatibility and security.
  • Update Existing Emails: Update any existing email templates and campaigns to use HTTPS links and images.
  • Monitor Browser Warnings: Stay informed about browser updates and security changes that might affect how emails with HTTP content are displayed.
  • Prioritize Security: Understand the security implications of using HTTP and educate your team on the importance of HTTPS.
  • Consider Gmail Optimization: Keep Google's preference for HTTPS in mind when designing your email marketing strategy.
Expert view

Expert from Email Geeks explains that while HTTP links might work for a while, browsers are increasingly warning about non-HTTPS links, and eventually, emails might not display correctly without HTTPS.

October 2023 - Email Geeks
Expert view

Expert from Email Geeks shares that Google favors HTTPS links in search rankings and that there is a likely benefit to using HTTPS in emails to Gmail.

March 2024 - Email Geeks
Expert view

Expert from Word to the Wise explains that using HTTPS builds user trust and protects sensitive information, preventing eavesdropping and man-in-the-middle attacks. It ensures that the connection between the user and the server is encrypted.

February 2023 - Word to the Wise

What the documentation says
4Technical articles

Using HTTPS for links and images in email marketing is important because it addresses multiple security and performance concerns. Mixed content (HTTPS pages loading HTTP resources) weakens security, leading browsers to block content or display warnings, thus impacting user experience. HTTPS protects data integrity by preventing attackers from tampering with transmitted data, ensuring recipients see the intended content. Additionally, HTTPS helps prevent man-in-the-middle attacks through encryption, safeguarding user data. Using HTTPS also enables the use of HTTP/2, which can improve website loading speed via header compression, multiplexing, and server push, enhancing overall user experience.

Key findings

  • Mixed Content Security Risk: Mixed content (HTTPS loading HTTP resources) weakens overall security, leading to browser warnings or content blocking.
  • Data Integrity: HTTPS protects data integrity, preventing attackers from altering transmitted information.
  • Man-in-the-Middle Prevention: HTTPS prevents man-in-the-middle attacks by encrypting the communication channel.
  • Performance Enhancement: HTTPS enables HTTP/2, improving website loading speed and user experience.

Key considerations

  • Avoid Mixed Content: Ensure that all resources loaded on HTTPS pages, including those linked from emails, are also served over HTTPS to avoid security warnings and blocking.
  • Prioritize Data Integrity: Implement HTTPS to guarantee the integrity of transmitted data, preventing unauthorized modifications.
  • Secure Communication Channels: Use HTTPS to encrypt communication channels and prevent man-in-the-middle attacks, protecting sensitive information.
  • Optimize Website Performance: Enable HTTP/2 to improve website loading speed and overall user experience, ensuring a faster and more efficient connection.
Technical article

Documentation from Mozilla Developer Network explains HTTPS protects data integrity, preventing attackers from tampering with resources transmitted over the network. This is crucial for ensuring email recipients see the intended content.

June 2024 - Mozilla Developer Network
Technical article

Documentation from DigiCert explains that HTTPS helps prevent man-in-the-middle attacks by encrypting the communication channel. This protects user data and ensures that attackers cannot intercept or modify the email content or linked resources.

February 2024 - DigiCert
Technical article

Documentation from Cloudflare shares using HTTPS enables the use of HTTP/2, which can improve website loading speed by enabling header compression, multiplexing and server push. This will improve website performance if this is the URL that is linked to. This contributes to a better overall user experience.

November 2024 - Cloudflare
Technical article

Documentation from Google Developers explains that mixed content (HTTPS page loading HTTP resources) can weaken security. Browsers block mixed content or display warnings, impacting user experience. Using HTTPS for all resources avoids these issues.

February 2024 - Google Developers