Summary
When email service providers (ESPs) wrap deep links, it can sometimes interfere with their intended functionality, especially for mobile app deep linking. A common workaround marketers consider is removing the http or https protocol from the start of the URL. While this might prevent ESP wrapping in some cases, it introduces a range of potential issues related to link validity, email client compatibility, and security.
Key findings
- Invalid URL format: Links without an explicit protocol (http:// or https://) are not technically complete absolute URLs and may not be parsed correctly by all email clients or webmail interfaces.
- Email client interpretation: Many email clients might default to http:// if no protocol is specified, which can lead to insecure connections or mixed content warnings if the target site is https://. This is why using HTTPS for email links is generally recommended.
- Deep linking reliance: Deep links depend on the operating system and installed apps to correctly interpret specific Uniform Resource Identifier (URI) schemes. Removing the standard web protocol can confuse this functionality, preventing the link from opening the app or the correct content.
- Loss of tracking: ESPs typically wrap links to enable click tracking, which provides valuable engagement data. Bypassing this mechanism means losing insight into how recipients interact with your emails.
- Security implications: Without an explicit https:// protocol, links could be susceptible to mixed content warnings or insecure redirects, diminishing user trust and potentially impacting your email deliverability.
Key considerations
- User experience: Broken or unreliable links lead to a poor user experience, which can increase complaints, reduce engagement, and ultimately harm your sender reputation.
- Indirect deliverability impact: While not a direct blocklist trigger, consistently broken links or a perception of insecurity can lead to negative user feedback, which can indirectly affect your email deliverability over time.
- Data loss: Forgoing ESP tracking means you lose crucial data on click-through rates, which are essential for optimizing campaign performance and understanding recipient behavior.
- Security risks: Prioritizing https:// for all links is a fundamental best practice for secure communication and maintaining user trust. Learn more about fixing mixed content warnings.
- Alternative solutions: It is advisable to explore specific deep linking features or custom configurations offered by your ESP that allow deep links to function correctly without requiring protocol removal or bypassing tracking.
What email marketers say
Email marketers frequently encounter challenges with ESP link wrapping, particularly when trying to implement deep links that direct users straight into a mobile application. While the idea of stripping HTTP/HTTPS from URLs to circumvent this wrapping might seem like a quick fix, it raises significant concerns among the marketing community about link functionality and the loss of critical engagement data.
Key opinions
- ESP-specific issues: Many marketers report that certain ESPs (e.g., Iterable, Salesforce Marketing Cloud) have aggressive link wrapping mechanisms that interfere with standard deep linking implementations.
- Workaround exploration: Marketers often seek unconventional methods, such as removing the protocol prefix from URLs, to prevent their ESP from altering their deep links.
- Uncertain deliverability impact: There's a mixed understanding among marketers regarding whether removing protocols directly impacts email deliverability or inbox placement.
- Functional concerns: A primary concern is whether such modified links will consistently function as intended across diverse email clients, devices, and operating systems.
- Data loss: Bypassing ESP wrapping inherently means sacrificing granular click-through tracking data, which is essential for campaign analysis and optimization, as highlighted in deep linking guides for developers.
Key considerations
- Thorough testing: Any non-standard link format or workaround should undergo extensive testing across all common email clients and device types to ensure consistent functionality.
- ESP consultation: Marketers are advised to consult with their ESP's support or documentation for official methods of implementing deep links that are compatible with their tracking systems, to avoid issues with ESP click tracking.
- Prioritize user experience: Ensuring that links reliably lead recipients to their intended destination is paramount for a positive user experience and maintaining a strong sender reputation.
- Data integrity: Weigh the perceived benefit of unwrapped deep links against the significant drawback of losing valuable click-through data and the ability to accurately measure campaign effectiveness.
Marketer view
Marketer from Email Geeks explains they have deep links that only work when their ESP doesn't wrap them. The only way to achieve this is by removing the HTTP or HTTPS protocol from the start of the link.
Marketer view
Marketer from Reddit suggests that bypassing link wrapping might compromise the reliability of click metrics. This happens because the ESP's usual tracking mechanisms are circumvented when links are modified.
What the experts say
Email deliverability experts consistently advise against deviating from standard URL protocols in email links. Their warnings stem from concerns about maintaining link functionality, ensuring security, and ultimately protecting sender reputation. While the immediate impact on spam filtering might be debated, the long-term consequences of unreliable or insecure links are clear.
Key opinions
- Invalid URL format: Experts emphasize that links without http:// or https:// are not valid absolute URLs, leading to unpredictable behavior across various email environments.
- Client interpretation: Email clients and browsers primarily expect explicitly defined protocols for secure and correct navigation. Omitting them can cause unexpected defaults or errors.
- Deep link complexity: The implementation of deep linking, especially for mobile applications, relies heavily on specific URI schemes. Altering standard web protocols can break this critical functionality.
- Indirect deliverability impact: While directly impacting deliverability less frequently, broken links or poor user experience resulting from non-standard URLs can lead to negative engagement signals. These signals can ultimately harm sender reputation and impact inbox placement.
- Security concerns: Omitting https:// risks defaulting to http://, which can result in mixed content issues, diminished user trust, or vulnerability to interception, as discussed in resources about deep link security.
Key considerations
- Adhere to standards: Sticking to RFC-compliant URL formats (e.g., http:// or https://) is critical for universal compatibility and predictable link behavior.
- Prioritize HTTPS: Always use HTTPS for all links when possible to ensure secure communication, protect user data, and build sender trust. This also helps avoid issues with unencoded URLs.
- Work with ESPs: Engage proactively with your ESP to find proper solutions for deep linking that accommodate their wrapping without compromising link functionality.
- Thorough testing: Before deploying any non-standard link structure, perform extensive testing across various email clients, devices, and operating systems to identify potential breakage points.
- Reputation impact: Consider the long-term impact on your sender reputation from a poor user experience caused by non-functional or insecure links. This can lead to increased complaints and lower engagement rates.
Expert view
Expert from Email Geeks (steve589) clarifies that a link like 'example.com' (without a protocol) is not a valid URL. Therefore, it may not function correctly with email clients, which expect a complete address.
Expert view
Deliverability expert from SpamResource.com advises against non-standard URL formats in emails. Such formats can trigger spam filters or lead to broken links for recipients, negatively impacting sender reputation.
What the documentation says
Official documentation for web standards and deep linking protocols consistently emphasizes the critical role of complete and correctly formatted URLs. This includes the explicit inclusion of HTTP or HTTPS protocols. This adherence is crucial not only for reliable functionality across diverse platforms but also for ensuring the security and integrity of online interactions initiated via email.
Key findings
- RFC compliance: RFCs (Request for Comments) for URIs, such as RFC 3986, define that a Uniform Resource Identifier typically requires a scheme component like 'http' or 'https' to be considered an absolute URL.
- Protocol-relative URLs: While protocol-relative URLs (e.g., //example.com) are valid in HTML for inheriting a webpage's protocol, their behavior in email clients without a base URL can be undefined or inconsistent, leading to unexpected link behavior.
- Security context: The absence of an explicit https:// protocol can cause browsers or email clients to default to http://, potentially resulting in insecure connections or mixed content warnings.
- Deep link URI schemes: Deep links often utilize custom URI schemes (e.g., myapp://path), which are distinct from web protocols. However, they still require proper formatting to ensure specific app handling and reliable functionality, as detailed in best practices for deep link vulnerabilities and best practices.
- Email client rendering: Email clients are not full-fledged web browsers and may not handle non-standard URL formats robustly. They could render them as unclickable plain text or fail to resolve them correctly.
Key considerations
- Absolute URLs for reliability: For maximum compatibility and predictability in email, always use fully qualified absolute URLs (e.g., https://example.com/path). This ensures consistent behavior regardless of the email client.
- HTTPS for security: Ensure all links use HTTPS to protect user data and maintain trust, aligning with modern web security practices and avoiding potential security risks.
- Standard deep link implementation: Follow recommended guidelines for implementing deep links that reliably work across different platforms (iOS, Android) and email clients. These guidelines typically require proper protocol inclusion.
- Understand ESP behavior: Consult your ESP's documentation for best practices regarding deep link integration and any methods to manage or disable link wrapping without compromising functionality or tracking.
Technical article
RFC 3986, the URI Generic Syntax standard, defines that a Uniform Resource Identifier (URI) typically includes a scheme component, such as 'http' or 'https'. This component is essential for the proper identification of the protocol being used.
Technical article
Mozilla Developer Network (MDN) documentation on URLs clarifies that while protocol-relative URLs (e.g., '//example.com') are useful in web contexts to automatically match the current page's protocol, their behavior can be unpredictable in environments like email. This is because there is no inherent base protocol from which to inherit.
Related resources
6 resources
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