Will including links from a different domain cause email spam filter or legal issues?

Key findings

• Link reputation: Spam filters and Real-time Blackhole Lists (RBLs) often assign their own reputation to links. If the linked domain has a poor reputation, regardless of the sending domain, it can impact deliverability. This is especially true for domains associated with spam or malicious activity.
• Domain mismatch: While some minor scrutiny might occur, a simple difference between the sending domain and the linked domain is not typically a major red flag for spam filters, particularly for legitimate business purposes.
• Legal implications: Legal regulations such as GDPR are concerned with consent for sending emails and the handling of personal data, not directly with whether links point to different domains owned by the same entity. Compliance rests on your email sending practices and data privacy policies.
• Authentication: Proper email authentication, including SPF, DKIM, and DMARC, is far more critical for establishing trust and ensuring deliverability than the domain of your links.

Key considerations

• Monitor link reputation: Regularly check the reputation of all domains you link to, especially if they are new or frequently used. Even if you own the linked domain, a poor reputation can affect your sender score.
• Maintain consistent branding: While not a deliverability issue directly, inconsistent branding can confuse recipients and lead to lower engagement or spam complaints. Ensure recipients understand the relationship between your sending domain and linked domains.
• Legal compliance focus: Prioritize obtaining clear consent from recipients and adhering to data privacy regulations like GDPR. The domains linked within your emails are secondary to these fundamental legal requirements.
• Use redirect links: If concerns persist, consider using your own redirect links on the sending domain to wrap external URLs. This can sometimes help manage how email clients perceive links and allow for better tracking, as discussed in our guide on best practices for email click tracking. An article by Spam Resource also explains why differing domains don't necessarily cause issues.

Key opinions

• Common practice: Many large-scale email systems and companies routinely send emails that link to domains distinct from their sending domain without deliverability problems.
• Recipient perception: The main concern for marketers is how recipients perceive the different domains. Inconsistent branding or suspicious-looking links could reduce trust, potentially impacting your email open rate and overall engagement.
• Focus on content: As long as the content is relevant and the user has opted in, the domain of the links is less likely to trigger spam filters than issues like too many links, or the quality of the content. Marketing advice often suggests focusing on how to avoid spam filters by improving content quality.
• Legal scope: Legal concerns like GDPR compliance are tied to how data is collected and used across email service providers (ESPs), not directly to the domains of the links themselves.

Key considerations

• User experience: Ensure the user experience is seamless. If recipients click a link and land on a domain that feels entirely disconnected from the email's sender, it can lead to confusion or mistrust. This is key to maintaining a good sender reputation.
• Content relevance: Always ensure the linked content is highly relevant to the email's topic and the recipient's interests. Irrelevant links, regardless of domain, can increase spam complaints.
• Transparency: Be transparent about the relationship between your sending domain and any linked domains. This builds trust with your audience.
• List segmentation: Consider if your audience lists for the two domains are distinct or overlap. If they overlap, ensure clear consent for both types of content.

Key opinions

• Link reputation is key: Many Mailbox Service Providers (MSPs) and blocklists assign individual reputations to links. Even if your sender reputation is strong, a link pointing to a domain frequently associated with spam can negatively impact your email's deliverability.
• Technical considerations: Experts advise that using tools to scan linked URLs can help identify if they have been flagged by spam traps or have a compromised reputation. This proactive approach helps in managing potential issues before they affect delivery.
• Beyond domain mismatch: The consensus is that a mere difference in domains between the sender and the linked content is not a primary spam trigger. Email filters are designed to detect malicious intent and deceptive practices, not simple corporate structure or branding differences.
• Legal focus on ESPs: Regarding legal aspects like GDPR, experts clarify that concerns arise more from the use of different Email Service Providers and how data is shared or processed between them, rather than the domains linked within the email itself.

Key considerations

• Proactive reputation management: Regularly monitor the reputation of your sending domain and any linked domains. This includes checking for blocklist entries using a blocklist checker.
• Authentication standards: Ensure all sending domains are fully authenticated with SPF, DKIM, and a robust DMARC policy. This foundational step significantly influences how ISPs trust your emails.
• Strategic link wrapping: Consider wrapping external links with your own redirect service, especially if you have concerns about the linked domain's reputation. This can provide a layer of control and consistency. More on how to safely use links in emails.
• Affiliate link caution: Be particularly careful with affiliate links, as these are often associated with spam and can trigger filters more easily, as highlighted in discussions around affiliate emails and sender deliverability.

Key findings

• Link scrutiny: Email filters can flag URLs, particularly if they are shortened, redirected suspiciously, or point to domains with a history of malicious activity. They examine the entire URL path for suspicious characteristics.
• Sender reputation: The reputation of your sending domain and IP address is a dominant factor in deliverability. This includes adherence to email authentication standards such as SPF, DKIM, and DMARC. A strong sender reputation can mitigate minor concerns about cross-domain links.
• Content quality: Documentation often emphasizes that email content, including the quality and relevance of links, impacts deliverability. Irrelevant or misleading links are more likely to cause issues than a simple domain difference.
• Legal basis: Legal frameworks like GDPR primarily focus on the lawful basis for processing personal data and the rights of data subjects. These rules require transparent data practices and consent, rather than specific rules on linking between owned domains.

Key considerations

• Active websites: Ensure that any website you link to is active and functioning. Sending email from an address linked to an inactive or blank website can raise suspicion with ISPs, affecting your deliverability, as noted by Mailjet's advice on avoiding spam filters.
• Link formatting: Documentation suggests ensuring links are correctly formatted and not excessive in number. Using clear, direct links is generally preferred over tactics that obfuscate the destination.
• Monitor blocklists: Regularly check if any of your linked domains appear on a public blocklist or blacklist. A domain on such a list can severely harm your deliverability, as detailed in our guide on what happens when your domain is on an email blacklist.
• Avoid suspicious patterns: Documentation from security platforms often warns against patterns commonly used by spammers, such as excessive numbers of links or links that redirect multiple times. These behaviors are more likely to trigger filters than cross-domain linking per se.