Does using HTTP links instead of HTTPS links affect email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 7 May 2025
Updated 17 Aug 2025
8 min read
The question of whether using HTTP links instead of HTTPS links impacts email deliverability is a common one. It touches on aspects of trust, security, and how mailbox providers evaluate incoming emails. While the direct answer isn't always a straightforward "yes" or "no" in terms of immediate spam folder placement, the nuances are critical for maintaining a strong sender reputation and ensuring your emails reach the inbox effectively.
For a long time, the consensus was that linking to an HTTP site directly wouldn't trigger spam filters purely because it lacked HTTPS. Mailbox providers were more concerned with other factors like sender authentication (SPF, DKIM, DMARC), content spamminess, and sender reputation. However, the internet has evolved significantly, and security has become paramount for all online interactions.
Today, while an HTTP link might not immediately cause your email to bounce or go to the spam folder, it signals a potential weakness in your email security practices. This can subtly erode trust with mailbox providers and recipients alike, making it a crucial consideration for anyone focused on email deliverability.
The direct impact on email deliverability
The direct impact on email deliverability
At a fundamental level, an HTTP link in itself is not typically a direct trigger for major email blocklists or spam filters to immediately flag your email as spam. Most filtering systems are primarily designed to detect malicious content, phishing attempts, or patterns associated with unsolicited bulk email. An unencrypted link alone often falls outside these immediate red flags.
However, major mailbox providers like Gmail and Yahoo often proxy HTTP links to ensure they are visible and functional within webmail sessions, which themselves operate over HTTPS. If a webmail client is loaded via HTTPS and tries to load HTTP content directly, it might block the content or display a security warning. Proxying helps prevent this broken experience, but it's an extra step that could, in theory, add latency or be bypassed in more stringent future security checks. You can learn more about Google's email sender guidelines.
While this proxying mitigates immediate visibility issues, it doesn't mean HTTP links are harmless. It simply means the immediate impact is often on user experience or display, rather than a direct block. However, the indirect effects on your sender reputation are where the true deliverability risks lie.
Security and trust implications
Security and trust implications
HTTPS (Hypertext Transfer Protocol Secure) encrypts the communication between a user's browser and a website. This encryption, provided by SSL/TLS certificates, protects data privacy and integrity. In contrast, HTTP transmits data in plain text, making it vulnerable to interception and modification, a significant security risk.
For email recipients, seeing an HTTP link in an email can erode trust. Modern web users are accustomed to secure connections, indicated by the padlock icon in their browser. An HTTP link might appear outdated or even suspicious. This perception can lead users to be hesitant in clicking the link, mark your email as spam, or even add your domain to their personal blocklist. These actions, while individual, collectively harm your sender reputation.
Furthermore, linking to an insecure site exposes users to potential man-in-the-middle attacks where malicious actors could intercept or alter the content exchanged between the user and the website. This risk is something mailbox providers are becoming increasingly aware of, even if it doesn't yet directly contribute to a spam score in the same way a blacklisted IP address might.
The risks of HTTP links in emails
User trust issues: Recipients may view HTTP links as unprofessional or insecure, leading to hesitation in clicking.
Data interception: Information transmitted over HTTP is unencrypted and vulnerable to eavesdropping.
Reputation harm: Consistent use of insecure links can negatively impact your long-term sender reputation with ISPs and recipients.
Browser warnings: Browsers may display warnings or block content from HTTP sites, especially within an HTTPS context.
Evolving ISP requirements and future outlook
Evolving ISP requirements and future outlook
Mailbox providers are continually refining their spam filtering algorithms to protect users from malicious content and improve the overall email experience. As more of the web moves to HTTPS, and Google publicly prioritizes secure websites in its search rankings, it's reasonable to infer that this emphasis on security will eventually extend more rigorously to email content. While no major ISP has explicitly stated that HTTP links will directly cause deliverability issues, the trend suggests it's a matter of time before it becomes a more significant factor.
Think of it as a quality signal. Just as image-only emails or excessive spam trigger words can negatively impact deliverability, outdated security practices might also contribute to a lower sender score over time. ISPs want to deliver emails that provide a safe and positive experience for their users. Insecure links contradict this goal.
Proactively transitioning all your links to HTTPS isn't just about current deliverability; it's about future-proofing your email program and building a reputation as a trustworthy sender. It aligns with global internet security trends and prepares you for stricter filtering rules that may emerge.
Current landscape
Direct deliverability: HTTP links do not typically cause immediate spam folder placement.
ISP handling:Mailbox providers often proxy HTTP links for compatibility in secure webmail clients.
User experience: Minimal impact beyond potential browser warnings or slight hesitation.
Future outlook
Increasing scrutiny: As the internet becomes more secure, HTTP links may become a more significant deliverability signal.
Reputation weighting: ISPs may increasingly factor link security into overall sender reputation scores.
User trust: Consumers will expect HTTPS by default, impacting engagement and spam complaints.
Best practices for linking in emails
Best practices for linking in emails
To ensure optimal email deliverability and maintain a strong sender reputation, always aim to use HTTPS for all links within your emails. This includes links to your website, landing pages, tracking links, and any other external resources. Implementing HTTPS on your entire web presence is a foundational step for email marketing success. This also applies to website SSL/TLS which is another important aspect.
Beyond the protocol, be mindful of the types of links you include. URL shorteners, particularly generic ones, can sometimes be viewed with suspicion by spam filters because they obscure the final destination. While they are not inherently bad, using full, clear HTTPS links from reputable domains is always preferable when possible. Some studies suggest that links themselves don't hurt deliverability, but the quality of the link matters, as seen in this article about email link open rates.
Another crucial aspect is the domain reputation of the sites you link to. If you consistently link to low-quality, untrusted, or blacklisted domains, it can negatively reflect on your own sender reputation, regardless of whether the link is HTTP or HTTPS. Always ensure that any external sites you link to are secure, reputable, and relevant to your content. This practice also extends to the impact of HTTP tracking links.
Finally, ensure that all your email tracking links also use HTTPS. Many email service providers (ESPs) offer the option to secure these links, which is important for maintaining consistency and trustworthiness across all elements of your email.
Indirect negative. Erodes trust, potential for future filtering.
Avoid whenever possible; redirect to HTTPS if necessary.
URL shorteners
Neutral to negative. Can be associated with spam. Use custom domains.
Use sparingly, prefer full links, or branded shorteners with HTTPS.
Links to untrusted/low reputation domains
Strong negative. Impacts your own sender reputation and spam score.
Only link to reputable, relevant, and secure domains.
Views from the trenches
Views from the trenches
Best practices
Always use HTTPS for all links, including tracking links, to demonstrate modern security practices.
Ensure your website and all landing pages linked from emails also use HTTPS.
Prioritize full, clear HTTPS links over generic URL shorteners to avoid potential spam flags.
Regularly audit all domains linked in your emails for their reputation and security.
Proactively migrate all content and tracking infrastructure to HTTPS to future-proof email deliverability.
Common pitfalls
Relying on HTTP links can erode recipient trust and lead to lower engagement over time.
Not all webmail clients display HTTP content correctly within HTTPS sessions, leading to broken experiences.
Using generic URL shorteners can make your links appear suspicious to spam filters and recipients.
Overlooking the security of linked landing pages, even if the email link is HTTPS, can still impact trust.
Delaying the adoption of HTTPS across your entire digital presence signals a lack of modern security commitment.
Expert tips
Embrace TLS for all web assets linked in emails; free certificate services make this highly accessible.
While not an immediate spam trigger, major mailbox providers are moving towards a TLS-first internet.
Consider the long-term impact on sender reputation and brand trust when choosing link protocols.
Consistency in using HTTPS across all your digital touchpoints reinforces a trustworthy sender identity.
Monitor user engagement with your links, as a decline could indicate trust issues stemming from security perceptions.
Expert view
Expert from Email Geeks says that while HTTP links should not directly impact deliverability, HTTPS is a best practice. Providers like Gmail often proxy HTTP links to ensure visibility in HTTPS webmail sessions.
2021-03-10 - Email Geeks
Marketer view
Marketer from Email Geeks says that currently, it's not primarily a spam issue, but it can affect whether links work correctly in some browsers. It might not become a direct delivery factor, but transitioning to HTTPS is still advisable.
2021-03-10 - Email Geeks
Final recommendations for link security
Final recommendations for link security
While using HTTP links instead of HTTPS links might not immediately condemn your emails to the spam folder, it poses significant risks to your long-term deliverability and sender reputation. The internet is rapidly moving towards a fully encrypted ecosystem, and email, as a vital communication channel, is not exempt from this shift. Ensuring all your links are HTTPS demonstrates a commitment to security and professionalism that mailbox providers and recipients value.
Adopting HTTPS for all your links isn't just about avoiding a potential negative impact; it's about proactively building a stronger, more trustworthy email program. This forward-thinking approach will safeguard your deliverability in the evolving landscape of email security and user expectations.
Gmail and 
Yahoo often proxy HTTP links to ensure they are visible and functional within webmail sessions, which themselves operate over HTTPS. If a webmail client is loaded via HTTPS and tries to load HTTP content directly, it might block the content or display a security warning. Proxying helps prevent this broken experience, but it's an extra step that could, in theory, add latency or be bypassed in more stringent future security checks. You can learn more about Google's email sender guidelines.
Google publicly prioritizes secure websites in its search rankings, it's reasonable to infer that this emphasis on security will eventually extend more rigorously to email content. While no major ISP has explicitly stated that HTTP links will directly cause deliverability issues, the trend suggests it's a matter of time before it becomes a more significant factor.
Mailbox providers often proxy HTTP links for compatibility in secure webmail clients.
