Do link shorteners impact email deliverability with ESP click tracking?

Key findings

• Spam Filter Behavior: Spam filters are inherently suspicious of public link shorteners because they are widely used to disguise malicious URLs.
• ESP Tracking: ESP click tracking typically redirects through a domain owned and managed by the ESP, which generally has a reputable sender score. This is standard practice for measuring engagement.
• Reputation Impact: The negative deliverability impact of a shortened link is primarily tied to the reputation of the specific link shortener domain used, rather than the act of shortening itself.
• Double Redirection: Applying a public link shortener on top of an ESP's click tracking creates a double redirection, which can not only trigger spam filters but also lead to browser security warnings, degrading the user experience.

Key considerations

• Prioritize ESP Tracking: Rely on your ESP's built-in click tracking over external link shorteners. ESPs manage the reputation of their tracking domains carefully.
• Avoid Public Shorteners: Steer clear of public link shortening services (e.g., bit.ly) in email campaigns to avoid negative sender reputation signals. This is a common factor influencing why emails go to spam.
• Custom Domains: If short links are necessary for branding or analytics outside of the ESP's capabilities, consider using a custom domain for your link shortening. This provides more control over your domain reputation and reduces reliance on shared, potentially compromised, public shortener domains.
• Transparent URLs: Wherever possible, display the full, unshortened URL to build trust with recipients and spam filters. Transparency in links is a key factor in improving email deliverability.

Key opinions

• Shorteners are problematic: Many marketers view link shorteners as inherently problematic for email deliverability, often being flagged as suspicious by spam filters.
• ESP tracking is different: They recognize that ESPs use redirect links for click tracking, but differentiate this from general public link shorteners due to the underlying domain's reputation.
• Obscuring destination: The primary concern with link shorteners is their ability to obscure the final destination, which is seen as a negative signal by email filters.
• Unnecessary usage: If an ESP already handles click tracking, using an additional link shortener is often deemed unnecessary and potentially harmful.

Key considerations

• Purpose of Shortener: Marketers should question the actual objective behind using a link shortener if their ESP already provides click tracking capabilities. It's crucial to understand factors influencing deliverability.
• Browser Behavior: Multiple redirects can annoy browsers and even trigger security errors for recipients, impacting the user experience negatively.
• Default ESP Settings: Some ESPs might not apply click-tracking redirects to the plain-text version of an email by default, which can influence decisions regarding link presentation in that specific format.
• Trust and Transparency: Opting for full, transparent URLs rather than shortened ones helps build trust with both recipients and email filters, contributing to better inbox placement.

Key opinions

• Reputation Risk: Experts highlight that public link shorteners are a significant source of spam and phishing attacks, leading to their inclusion on many blacklists and blocklists, which negatively affects deliverability.
• Lack of Transparency: The obfuscation of the final destination URL by shorteners is a major red flag for spam filters, as it makes it difficult to assess the link's legitimacy.
• ESP Tracking Domain Authority: ESPs typically use dedicated subdomains for click tracking that they actively monitor and maintain for high reputation, distinguishing them from generic link shorteners.
• User Experience Degradation: Multiple redirects (from shortener to ESP tracking to final destination) can lead to slower load times and potential browser warnings, harming recipient trust.

Key considerations

• Domain Reputation Management: If using any form of link shortening, ensure it's on a dedicated, custom domain whose reputation you actively manage and protect, similar to how ESPs handle their tracking domains. Monitoring your email domain reputation is vital.
• Avoid Chains of Redirects: Minimize the number of redirects a link goes through. Each redirect presents another opportunity for filtering and can negatively impact deliverability.
• Content Scanning: Understand that links, as part of your email content, are heavily scrutinized by spam filters. Poor link choices can lead to deliverability problems, regardless of other positive sender signals.
• Phishing Associations: Given that shortened links are often associated with phishing, using them can trigger alerts within filtering systems that aim to protect users from malicious content. For insights on why short URLs are risky, this perspective is key.

Key findings

• Security Concerns: Documentation often points out that shortened URLs are frequently exploited in phishing and malware distribution, leading email security systems to view them as highly suspicious.
• Domain Trust: Mailbox providers (ISPs) rely heavily on domain reputation. Public link shortener domains often have mixed or poor reputations due to widespread abuse, which can trigger spam filters.
• Click Tracking Mechanisms: ESPs implement click tracking using their own dedicated domains, which are designed to maintain good standing with ISPs and do not carry the same negative connotations as public shorteners.
• User Expectation: Transparent, full URLs allow recipients to clearly see where a link will take them, fostering trust. Shortened URLs can erode this trust.

Key considerations

• Compliance and Security Protocols: Adhere to best practices that prioritize security and transparency in email content. This includes careful consideration of all links to avoid triggering email blacklists or blocklists.
• Maintaining Sender Reputation: Focus on practices that build and maintain a strong sender reputation across all aspects of your email campaigns, including link hygiene. This will impact the overall health of your email program and address common deliverability issues.
• ISP Filtering Logic: Be aware that ISPs use sophisticated filtering logic that takes into account the history and reputation of all domains present in an email, including link domains.
• Accurate Engagement Metrics: For accurate click tracking, rely on systems designed for this purpose (like ESPs or analytics platforms) that do not introduce deliverability risks. Documentation from Bloomreach notes that features like Reliable Email Clicks can ensure metrics reflect genuine user engagement, free from bot influence.