Summary
The presence of multiple or long links in emails can significantly impact deliverability. Several factors contribute to this, including the reputation of linked domains, the quantity and length of URLs, the use of link cloaking or URL shorteners, and even the anchor text employed. High-quality links to reputable domains are crucial. Overly long URLs with excessive tracking parameters and numerous redirects are detrimental. Tracking domains require active reputation management, and the choice of link tracking services is important. A balanced email design is essential, especially regarding the ratio of image links to text. Furthermore, the URL structure itself (HTTPS vs HTTP) affects deliverability. Microsoft's Safe Links can rewrite URLs, adding to their length. Ultimately, a multi-faceted approach is needed to ensure links don't negatively impact email deliverability.
Key findings
- Domain Reputation: Linking to low-reputation or spammy domains damages sender reputation and deliverability. Google considers the reputation of linked domains.
- URL Quantity and Length: Including too many links and/or excessively long URLs, particularly with tracking parameters, triggers spam filters.
- Link Cloaking and Redirects: Link cloaking is strongly associated with phishing, while excessive redirects raise suspicion and harm deliverability.
- URL Shorteners: While convenient, URL shorteners can be flagged by spam filters, especially from lesser-known services. Branded links are preferrable.
- Anchor Text Matters: Certain words or phrases in anchor text can trigger spam filters.
- Tracking Domain Reputation: Poorly managed tracking domain reputations significantly impact deliverability; monitor blocklists and user complaints.
- Image and Text Balance: Too many linked images and not enough text increases the chance of being flagged as spam.
- Broken Destination: Redirects can lead to deliverability issues if the destination is blocked.
- BlockListed Link Tracker: Using a link tracker service that is on blocklists will negatively affect your deliverability.
- URL Structure: URL structure (HTTPS vs HTTP, hosted file, redirects) impacts deliverability.
Key considerations
- Prioritize Link Quality: Focus on linking to reputable and relevant websites.
- Keep URLs Concise: Minimize tracking parameters or use branded links.
- Manage Tracking Domains: Actively monitor and manage the reputation of tracking domains for block listings and complaints.
- Use Natural Anchor Text: Employ natural and relevant anchor text, avoiding spammy keywords.
- Secure Linked Websites: Ensure linked websites are secure (HTTPS) and have valid SSL certificates.
- Limit Redirects: Minimize the use of redirects and, when possible, link directly to the final destination.
- Maintain Balance: Maintain a healthy text to image ratio within your emails.
- RFC Email Syntax: Ensuring that your links adhere to email syntax standards to avoid being flagged as spam.
What email marketers say
12 marketer opinions
Multiple and/or long links in emails can negatively affect deliverability in various ways. Too many links, especially to domains with poor reputations or those that are frequently blocklisted, can trigger spam filters. Long URLs, particularly those with excessive tracking parameters, are also problematic. Link cloaking and excessive redirects are red flags, as are the use of URL shorteners, especially those less reputable. Even the anchor text used in links can influence spam scores. Good practices include using a limited number of high-quality links, ensuring linked websites are secure and have valid SSL certificates, using natural and relevant anchor text, warming up dedicated tracking domains, and avoiding redirects.
Key opinions
- Reputation Matters: The reputation of linked domains significantly impacts deliverability. Linking to spammy or low-reputation sites harms your sender reputation.
- Quantity and Length: Too many links and excessively long URLs with excessive tracking parameters can trigger spam filters.
- Link Cloaking is Bad: Techniques like link cloaking are strong indicators of phishing or spam and severely damage deliverability.
- URL Shorteners: While convenient, URL shorteners can be flagged as suspicious by spam filters, especially if from lesser-known services.
- Anchor Text: Using spam-like words or phrases as anchor text can trigger spam filters.
- Tracking Domain Warmup: Warming up a dedicated tracking domain improves deliverability when using link tracking heavily.
- Redirects: Excessive redirects can make links appear suspicious, negatively impacting deliverability.
- HTTPS/SSL: Websites that use HTTPS and have SSL certificates have improved trust and deliverability.
- Image and Text Balance: Having too many linked images without enough text causes the email to go to the spam folder.
Key considerations
- Prioritize Quality Links: Focus on a limited number of links to reputable and relevant websites.
- Keep URLs Concise: Minimize tracking parameters and consider using branded links instead of generic URL shorteners.
- Monitor Reputation: Actively manage and monitor the reputation of your tracking domains, looking for blocklistings or user complaints.
- Use Natural Anchor Text: Avoid using spam-like keywords or phrases as anchor text for links.
- Secure Linked Sites: Ensure the websites you are linking to are secure and have valid SSL certificates.
- Reduce Redirects: Try to link directly to the final destination whenever possible, minimizing the use of redirects.
Marketer view
Marketer from Email Geeks suggests that the reputation associated with those links may be having an impact, and including more links could increase the risk of URLs carrying less-than-ideal reputations.
29 May 2023 - Email Geeks
Marketer view
Email marketer from Litmus Blog explains that certain words or phrases commonly used in spam emails, when used as anchor text in links, can trigger spam filters. It's important to use natural and relevant anchor text.
11 Feb 2023 - Litmus Blog
What the experts say
5 expert opinions
The impact of multiple or long links on email deliverability is influenced by several factors. Research into academic spam filter publications may reveal more insights. Using link trackers on blocklists can negatively affect deliverability, especially with custom tracking domains. URL structure, including HTTPS vs HTTP, file hosting, and redirects, also plays a role. Poorly managed tracking domain reputations directly impact deliverability, necessitating monitoring for blocklists and user complaints. Redirection can lead to deliverability issues if the destination becomes blocked.
Key opinions
- Link Tracker Blocklists: Using link tracking services on blocklists negatively affects deliverability, particularly with custom tracking domains.
- URL Structure: URL structure (HTTPS vs HTTP, hosted file, redirects) impacts deliverability.
- Tracking Domain Reputation: Poorly managed tracking domain reputations negatively affect deliverability.
- Redirects Can be Dangerous: Redirection can lead to deliverability issues if the destination is blocked.
Key considerations
- Investigate Academic Research: Explore academic spam filter publications for more information on the impact of links on deliverability.
- Check Tracker Status: Ensure your link tracker service is not on any blocklists before using it.
- URL Best Practices: Use HTTPS, host files directly if possible, and minimize redirects in your URL structure.
- Monitor Tracking Domains: Actively monitor tracking domain reputations for blocklistings and user complaints.
- Limit Redirects: If you're using redirects, be wary of the final website being blocked at some point.
Expert view
Expert from Word to the Wise states that redirection can have issues - stating if the destination gets blocked, you're sending traffic to a site that is now blocked, and it does end up impacting deliverability.
8 Mar 2022 - Word to the Wise
Expert view
Expert from Spam Resource explains that your URL structure (HTTPS vs HTTP) and whether the URL leads to a file hosted on your domain can affect deliverability. They suggest avoiding redirects in the URL.
3 Sep 2021 - Spam Resource
What the documentation says
3 technical articles
Google Postmaster Tools indicates that the reputation of linked domains affects deliverability, meaning linking to low-reputation domains can hurt your sender reputation. RFC-Editor states that while RFC standards don't directly address deliverability, they define email syntax; non-standard links can increase spam scores. Microsoft Defender's Safe Links feature rewrites URLs for inspection, potentially increasing their length.
Key findings
- Domain Reputation: Google considers the reputation of linked domains when determining email deliverability.
- Email Syntax: Non-standard or malformed links, violating RFC standards, can increase spam scores.
- Safe Links URL Rewriting: Microsoft Defender's Safe Links feature can rewrite URLs, potentially increasing their length.
Key considerations
- Vet Linked Domains: Ensure that the domains you link to have a good reputation to avoid harming your sender reputation.
- Adhere to Standards: Ensure that your links adhere to email syntax standards to avoid being flagged as spam.
- Safe Links Impact: Be aware that services like Microsoft Defender's Safe Links may rewrite your URLs, potentially affecting their length.
Technical article
Documentation from Google Postmaster Tools explains that Google considers the reputation of domains linked to in your emails when determining deliverability. Linking to low-reputation or spammy domains can harm your sender reputation.
22 Sep 2022 - Google
Technical article
Documentation from RFC-Editor explains that while RFCs don't directly address deliverability, they define standards for email syntax. Non-standard or malformed links can increase spam scores.
14 Apr 2025 - RFC-Editor
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