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Does linking directly to PDFs from emails negatively affect deliverability?
Summary
Linking directly to PDFs from emails doesn't automatically doom deliverability, but it introduces several potential pitfalls. While some experts believe direct links are acceptable, especially when the PDF is hosted on a reputable server, the consensus leans toward caution. Key concerns include the risk of PDFs containing malware, triggering spam filters, or being blocked by mail clients. A common recommendation is to link to a webpage containing the PDF instead, which allows for better tracking, branding opportunities, and a more user-friendly experience. Furthermore, maintaining a strong sender reputation by adhering to email authentication best practices (DKIM, SPF), regularly checking link reputation, and avoiding links to suspicious sites are crucial for ensuring positive deliverability outcomes, regardless of whether you're linking to PDFs or other types of content.

Key findings

  • Not a Guaranteed Problem: Linking directly to PDFs doesn't always negatively affect deliverability.
  • Malware & Spam Risk: PDFs can contain malware or be flagged as spam, harming sender reputation.
  • URL Reputation Matters: The reputation of the website hosting the PDF significantly impacts deliverability.
  • Authentication Is Key: Proper DKIM and SPF setup helps establish trust and improve deliverability.
  • Landing Page Benefits: Linking to a webpage with the PDF provides better tracking, branding, and user experience.

Key considerations

  • Scan PDFs: Always scan PDFs for malware before linking to them in emails.
  • Check URL Reputation: Verify the reputation of the website hosting the PDF using link checkers.
  • Implement Authentication: Ensure DKIM and SPF records are correctly configured for your sending domain.
  • Consider a Landing Page: Evaluate the benefits of using a webpage to present the PDF instead of a direct link.
  • Monitor Deliverability: Track your deliverability rates to identify any issues related to PDF links.
  • Ensure PDF Accessibility: Make sure that the PDF is able to be read by people of varying accessibility requirements.
What email marketers say
9 marketer opinions
Linking directly to PDFs from emails doesn't definitively harm deliverability, but it presents potential risks. Experts recommend caution, emphasizing the importance of a reputable PDF source and secure hosting. Some suggest avoiding direct PDF links altogether in favor of linking to a webpage containing the PDF, allowing for better tracking, branding, and user experience. A key concern is that PDFs can be flagged as spam or harbor malicious content, negatively affecting sender reputation. General email deliverability best practices, such as maintaining a clean domain, using link checkers, and avoiding suspicious URLs, also apply.

Key opinions

  • Direct harm?: Linking directly to PDFs doesn't automatically harm deliverability.
  • Reputable Source: The reputation of the PDF source is critical; untrusted sources can trigger spam filters.
  • Content Matters: Malicious content within the PDF can negatively impact sender reputation.
  • Landing Page Alternative: Linking to a webpage containing the PDF offers improved tracking, branding, and UX.
  • General Link Risks: General link best practices (checking links, avoiding suspicious sites) apply to PDF links too.

Key considerations

  • PDF Reputation: Evaluate the reputation of the domain hosting the PDF.
  • Malware Checks: Ensure PDFs are scanned for malware before linking.
  • User Experience: Consider the user experience; a webpage might be more informative and engaging than a direct PDF download.
  • Tracking: If tracking PDF downloads is important, a landing page is essential.
  • Landing Page Value: Consider adding value to a landing page by including a call to action, upsell or any extra useful information for the client.
Marketer view
Email marketer from Mailjet Blog explains that linking directly to PDFs doesn't directly harm deliverability if the PDF is legitimate and hosted on a reputable server. However, they caution that if the PDF is flagged as spam or contains malicious content, it can negatively impact your sender reputation.
22 Jun 2023 - Mailjet Blog
Marketer view
Email marketer from HubSpot shares tips on email deliverability and how to ensure your emails are not flagged as spam. They do not mention PDFs but say to ensure your links lead to trusted sites.
30 Dec 2024 - HubSpot
What the experts say
4 expert opinions
While direct PDF links aren't inherently detrimental, experts highlight potential risks to email deliverability. Concerns include malware within PDFs, enterprise mail filters scrutinizing links, and the impact of URL reputation. Testing direct PDF links is advised, with a fallback option of using a 'download' link if issues arise. Linking to webpages with PDFs is favored for enhanced tracking, branding, and user support. Google's potential penalties based on landing page content should also be considered.

Key opinions

  • Malware Risk: PDFs can harbor malware, leading to filtering or deliverability issues.
  • URL Reputation: The reputation of the URL hosting the PDF significantly impacts deliverability.
  • Tracking Limitations: Direct PDF links offer less tracking visibility compared to webpage links.
  • User Support: Troubleshooting broken PDF links is harder than broken website links.

Key considerations

  • Test & Monitor: Thoroughly test direct PDF links and closely monitor deliverability.
  • Reputation Management: Ensure the PDF hosting domain has a positive reputation.
  • Alternative Link: Provide a 'download' link as a fallback if direct links fail.
  • Webpage Option: Prefer linking to a webpage containing the PDF for better tracking and branding.
Expert view
Expert from Email Geeks explains links to PDFs should be tracked by ESPs, but there is less visibility on the website performance of the link. Ideally, the PDF should be on a page for branding/upselling opportunities. It could be harder for the recipient to resolve any issues if the PDF link breaks directly from an email, compared to a website.
5 Nov 2024 - Email Geeks
Expert view
Expert from Email Geeks doubts linking directly to PDFs will cause issues and says it's better than attaching PDFs to emails, although PDFs can contain malware and enterprise mail filters might check the links.
27 Feb 2023 - Email Geeks
What the documentation says
3 technical articles
While direct PDF links aren't specifically addressed, email deliverability documentation from Google, RFC and Microsoft offers relevant guidance. Authenticating your sending domain with DKIM and SPF builds trust, improving deliverability for all links, including PDFs. Email clients may block unsafe file types, which often includes PDFs, highlighting the importance of ensuring your PDF content is secure. Overall email sending best practices such as properly formatted emails and freedom from malicious content are key to avoiding deliverability issues.

Key findings

  • Domain Authentication: Properly configuring DKIM and SPF enhances sender reputation and improves deliverability.
  • File Type Blocking: Mail clients may block PDFs due to security concerns.
  • Content Security: Ensuring emails are free of malicious content is essential for good deliverability.

Key considerations

  • Domain Setup: Verify DKIM and SPF records for your sending domain are correctly configured.
  • Security Scans: Scan PDFs for malware before sending to minimize risk.
  • Email Formatting: Adhere to email formatting best practices.
Technical article
Documentation from RFC says that mail clients are able to block file types that are deemed unsafe. PDFs are a commonly targetted file type.
19 Nov 2022 - RFC
Technical article
Documentation from Google Sender Guidelines highlights the importance of aligning your sending domain with your DKIM and SPF records. Although it does not directly mention PDFs, using a custom domain helps build trust, which can positively impact deliverability when linking to PDFs or other external content.
24 Apr 2022 - Google Sender Guidelines
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