Do secure HTTPS links improve email deliverability?
Michael Ko
Co-founder & CEO, Suped
Published 17 Jun 2025
Updated 15 Aug 2025
7 min read
The question of whether using secure HTTPS links improves email deliverability is a common one in the email marketing and security space. Many senders want to ensure their messages reach the inbox reliably, and the security of embedded links can play a subtle, yet important, role in how email providers assess incoming mail.
While it might not be the single most impactful factor, the shift towards a more secure web environment means that email service providers (ESPs) and mailbox providers (MBPs) are increasingly looking at the overall security posture of emails. This includes the links embedded within them. Using HTTPS for all links, including tracking links and images, contributes to building a stronger sender reputation over time.
Understanding this aspect of email security can help you optimize your campaigns and ensure your messages are perceived as trustworthy by both recipients and the systems that protect their inboxes. It's about providing a consistent, secure experience from the moment an email is opened to when a link is clicked.
The role of HTTPS in trust and security
HTTPS links, secured by SSL/TLS certificates, encrypt the data exchanged between a user's browser and the website. This encryption protects against eavesdropping and tampering. When these secure links are included in emails, they signal reliability to email clients and anti-spam filters.
An email containing an HTTP link, on the other hand, might raise a red flag. Unsecured links are often associated with phishing attempts, malware distribution, or other malicious activities. Therefore, while a single HTTP link might not immediately tank your deliverability, a pattern of using them can negatively impact your domain reputation and lead to emails landing in spam folders. It's about consistency and adhering to modern security standards.
The underlying principle is trust. Email providers are constantly evaluating whether a sender is legitimate and safe. Secure links contribute positively to that assessment, demonstrating a commitment to recipient security and a professional approach to email communication.
ISP perspectives and tracking
Major mailbox providers, such as Gmail and Outlook, are increasingly prioritizing emails with HTTPS links, directly impacting your chances of landing in the inbox. Their sophisticated spam filters analyze numerous factors to determine an email's legitimacy, and the security of embedded URLs is certainly one of them. While a secure link on its own isn't a magic bullet, it forms part of a larger ecosystem of positive signals.
It is important to differentiate between HTTPS links within the email content and TLS encryption for the mail server itself. While both relate to security, mail server SSL certificates do not directly impact spam filtering in the same way that domain authentication protocols like SPF, DKIM, and DMARC do. Our focus here is on the URLs recipients click on.
For email marketers, this means ensuring that any tracking links, image URLs, and destination pages are all served over HTTPS. If your email service provider (ESP) uses HTTP tracking links, it could potentially hinder your deliverability, as unsecure elements might be flagged by modern spam filters. This also extends to how your website handles redirects and HSTS (HTTP Strict Transport Security) policies, which can force HTTP requests to HTTPS.
Many companies are now setting HSTS policies on their websites that force all traffic over HTTPS, often including subdomains. This means that if a recipient clicks an HTTP tracking link, their browser might try to upgrade it to HTTPS, which could lead to issues if your ESP's tracking domain doesn't support HTTPS. This misalignment can result in broken links or, worse, a negative signal to mailbox providers. Therefore, ensuring your entire link journey, from email to final destination, is HTTPS-secured is crucial. You can learn more about domain mismatches and protocol discrepancies in our other guides.
Practical implementation for marketers
Implementing HTTPS for all your email links is a straightforward process that provides clear benefits. Most modern ESPs offer this as a standard feature, or at least as an option. If your current setup uses HTTP links for tracking or images, it's worth investing in updating your configuration. This is also important for improving sender reputation.
HTTP links
Security risk: Data exchanged over HTTP is unencrypted and vulnerable to interception or tampering.
Deliverability impact: May be flagged by spam filters, potentially leading to lower inbox placement or even blacklisting (blocklisting).
User trust: Browsers may warn users about insecure connections, eroding confidence in your brand.
Beyond deliverability, using HTTPS links also enhances the recipient's experience and builds trust. When users click a link, seeing the padlock icon and "HTTPS" in their browser's address bar reassures them that they are visiting a secure site. This positive experience can lead to higher engagement and a better perception of your brand, especially given the overall trend towards enhanced security online.
It's also important to avoid URL shorteners that don't use HTTPS or that have a poor reputation, as these can be red flags for spam filters. Stick to full, clean, and secure links whenever possible to maintain optimal deliverability and user trust.
Beyond links: A holistic view
While secure links are beneficial, they are just one piece of the complex deliverability puzzle. A robust email strategy incorporates multiple best practices to ensure messages consistently reach the inbox.
Email authentication: Implement SPF, DKIM, and DMARC records to verify your sending domain and prevent spoofing. This is arguably the most critical factor for inbox placement.
List hygiene: Regularly clean your email lists to remove inactive or invalid addresses, reducing bounces and spam trap hits.
Content quality: Avoid spammy language, excessive capitalization, and poor formatting that could trigger spam filters. Provide valuable and relevant content.
Sender reputation monitoring: Keep an eye on your sender score and monitor for any blacklist (blocklist) appearances. Addressing issues promptly is key to recovery.
Engagement metrics: High open rates, click-through rates, and low complaint rates signal positive engagement to ISPs, boosting your deliverability.
By focusing on these foundational elements, alongside using secure HTTPS links, you build a resilient deliverability program that maximizes your chances of reaching the inbox. Remember, every positive signal contributes to your overall sender reputation and helps prevent your emails from being flagged as spam or falling onto a public or private blacklist.
Views from the trenches
Best practices
Always use HTTPS for all links, including tracking and images, to improve email trust and deliverability.
Ensure your email service provider supports HTTPS for custom tracking domains and redirects.
Regularly audit your email content for any insecure (HTTP) links and update them to HTTPS.
Implement email authentication (SPF, DKIM, DMARC) as a foundational step for deliverability.
Common pitfalls
Ignoring browser warnings about insecure links, which erode recipient trust.
Using URL shorteners that lack HTTPS or have a poor sender reputation.
Not configuring custom tracking domains with SSL, causing mismatches with HSTS policies.
Believing that HTTPS links alone will solve all deliverability issues without other authentications.
Expert tips
Consider that major mailbox providers, like Google, favor HTTPS in search and likely extend this preference to email links.
Recognize that while HTTPS might be a minor signal now, it could become a stronger factor if more good senders adopt it.
Understand that transitioning to HTTPS can be complex for ESPs, especially with old infrastructure, but it's a necessary investment.
Be aware that browsers, like Chrome, are increasingly forcing HTTPS upgrades, making HTTP links problematic for user experience.
Expert view
Expert from Email Geeks says Gmail's preference for HTTPS in web search indicates they likely apply similar value to HTTPS links within email content, making it a reasonable assumption for improved deliverability.
2020-12-21 - Email Geeks
Marketer view
Marketer from Email Geeks says that while the impact of HTTPS on delivery might currently be low, it is still a good practice to use secure links, even if the direct deliverability benefit is not immediately obvious.
2020-12-21 - Email Geeks
The path to better inbox placement
Ultimately, secure HTTPS links do improve email deliverability, albeit as one of many contributing factors. They enhance trust, improve sender reputation, and align your email practices with modern web security standards. While they may not be the sole determinant of inbox placement, neglecting them can certainly lead to deliverability challenges, especially as mailbox providers become stricter.
For optimal results, integrate HTTPS links as part of a comprehensive deliverability strategy that includes strong authentication, good list management, and engaging content. This holistic approach will ensure your emails are not only secure but also consistently reach your audience's inboxes.
Gmail and 
Outlook, are increasingly prioritizing emails with HTTPS links, directly impacting your chances of landing in the inbox. Their sophisticated spam filters analyze numerous factors to determine an email's legitimacy, and the security of embedded URLs is certainly one of them. While a secure link on its own isn't a magic bullet, it forms part of a larger ecosystem of positive signals.
