How to check if Sendlane complies with RFC 8058 for one-click unsubscribe?
Matthew Whittaker
Co-founder & CTO, Suped
Published 13 Jun 2025
Updated 19 Aug 2025
7 min read
The advent of new email sender requirements from major mailbox providers like Google and Yahoo has placed a renewed focus on one-click unsubscribe functionality, specifically compliance with RFC 8058. This standard is crucial for ensuring recipients can easily opt out of unwanted emails, which in turn helps maintain a good sender reputation and improves email deliverability.
As businesses increasingly rely on Email Service Providers (ESPs) like Sendlane for their marketing communications, it's vital to confirm that these platforms adhere to these technical requirements. Non-compliance can lead to significant issues, including emails landing in spam folders or even being rejected outright by major inbox providers. This directly impacts your reach and the effectiveness of your campaigns.
Verifying RFC 8058 compliance, especially with a third-party provider, can sometimes be confusing. I'll explain what RFC 8058 entails and how you can determine if Sendlane is properly implementing it for your emails, ensuring your messages reach their intended recipients.
Understanding RFC 8058 for one-click unsubscribe
RFC 8058, officially known as "Signaling One-Click Functionality for List Email Unsubscribe," standardizes how email recipients can unsubscribe with a single click. Unlike traditional unsubscribe links that often redirect users to a landing page or require multiple steps, RFC 8058 leverages specific email headers to enable a true one-click process directly within the email client interface.
The core of this standard involves two crucial email headers: List-Unsubscribe and List-Unsubscribe-Post. The List-Unsubscribe header provides a URL or an email address (mailto link) for unsubscribing, while the List-Unsubscribe-Post: List-Unsubscribe=One-Click header signals that a POST request to the specified URL should trigger the unsubscribe without further user interaction. This streamlines the process for recipients, reducing friction and improving the overall user experience.
For bulk senders, compliance is no longer optional. Google and Yahoo, among others, now mandate this standard. Failure to comply can result in your emails being marked as spam or even blocked, severely impacting your email deliverability. It's about respecting user preferences and building trust, which ultimately benefits your sender reputation and ensures your messages reach the inbox.
How to check for RFC 8058 compliance in Sendlane emails
The most reliable way to check for RFC 8058 compliance in your Sendlane emails is by inspecting the raw email headers. When you receive a campaign email sent through Sendlane, you can typically view these headers in your email client. Look for the List-Unsubscribe and List-Unsubscribe-Post headers. They should be present and correctly formatted with an HTTPS URL for the POST method.
You can also use an email header analyzer or a tool like AboutMy.Email to automate this check. However, be aware that some ESPs, including potentially Sendlane, might block requests from such testing services, leading to inconclusive results. If you encounter issues with these tools, manual header inspection or direct communication with Sendlane support is the next step.
It's important to differentiate between a simple unsubscribe link in the email footer and true one-click unsubscribe functionality via headers. While Sendlane provides a footer link, RFC 8058 requires the specific headers to be present and correctly configured. A simple link in the footer, even if it leads to a one-click process on a landing page, is not the same as the header-based RFC 8058 compliance that mailbox providers are now enforcing. This distinction is crucial, as some support representatives might confuse the two.
Traditional footer link
Visibility: Explicitly displayed in the email body, usually at the bottom.
Process: Often redirects to a web page where the user completes the unsubscribe.
Compliance: May meet basic legal requirements but not the enhanced one-click standard.
RFC 8058 header-based
Visibility: Invisible to the recipient, implemented in email metadata.
Process: Allows direct unsubscribe from the email client, often a single click.
Compliance: Meets new bulk sender requirements by Google and Yahoo.
Common pitfalls and troubleshooting Sendlane compliance
If Sendlane's support suggests that a footer link suffices for RFC 8058 compliance, this indicates a misunderstanding. The standard specifically refers to headers. A support representative might not have the full technical knowledge of email deliverability requirements. It's crucial to escalate the issue to their technical or deliverability team to ensure they understand the specific nature of RFC 8058 and its implementation.
Another potential issue is that Sendlane might have implemented the headers, but the POST endpoint (the URL that receives the unsubscribe request) could be silently blocking or rate-limiting incoming requests. This could explain why automated checks like AboutMy.Email don't register the unsubscribe, even if delivery reports show the email was received. This type of issue is harder to diagnose without direct insight from Sendlane's engineering team.
Additionally, for complete compliance and proper authentication, the List-Unsubscribe and List-Unsubscribe-Post headers should be included in your DKIM signature. If they are not, email clients may not trust these headers, impacting deliverability. When troubleshooting, ensure all relevant headers are properly signed according to email authentication protocols.
Ensuring ongoing deliverability with Sendlane
Beyond verifying RFC 8058 compliance, ensuring strong email deliverability with Sendlane involves a holistic approach. Regularly monitor your email deliverability rates and sender reputation using tools like Google Postmaster Tools. Pay attention to spam rates, IP reputation, and domain reputation. If you see dips, investigate promptly. Many providers offer feedback loops that can provide insights into subscriber complaints.
Maintaining a clean and engaged email list is another critical factor. Regularly remove inactive subscribers and hard bounces. Sending emails to disengaged users or invalid addresses can significantly harm your sender reputation and lead to being placed on email blocklists or blacklists. Always prioritize quality over quantity in your subscriber base.
Lastly, ensure that your email content is relevant, valuable, and not spammy. High engagement rates (opens, clicks) signal to mailbox providers that your emails are desired, further bolstering your deliverability. Combine technical compliance like RFC 8058 with strong content and list management for optimal results with Sendlane or any other ESP.
Views from the trenches
Best practices
Always inspect raw email headers to verify RFC 8058 compliance, looking for both List-Unsubscribe and List-Unsubscribe-Post headers with an HTTPS URL.
Prioritize direct communication with your ESP's deliverability team when troubleshooting, especially if front-line support seems misinformed about technical standards.
Ensure that all relevant email headers, including unsubscribe headers, are properly included in your DKIM signature to maintain trust with mailbox providers.
Regularly clean your email list by removing inactive subscribers and invalid addresses to improve sender reputation and avoid blacklisting (or blocklisting).
Common pitfalls
Mistaking a standard unsubscribe link in the email footer for RFC 8058 one-click unsubscribe compliance, as the latter relies on specific email headers.
Assuming that if your ESP's delivery reports show success, their one-click unsubscribe is fully compliant, without verifying header implementation.
Failing to escalate technical issues beyond initial support, especially when dealing with nuanced standards like RFC 8058.
Overlooking silent blocking or rate limiting of unsubscribe endpoints by your ESP, which can cause compliance checks to fail without clear error messages.
Expert tips
Use email header analysis tools, but be prepared for ESPs to suppress test emails from known testing services.
For optimal deliverability, ensure the List-Unsubscribe header also includes a mailto: option in addition to the HTTPS URL.
Regularly review mailbox provider guidelines, as requirements for one-click unsubscribe and other standards can evolve.
Implement DMARC with a monitoring policy to gain insights into email authentication and potential compliance issues.
Marketer view
Marketer from Email Geeks says they find it extremely hard to believe Sendlane doesn't support RFC 8058, especially given the efforts of their previous founder regarding this.
2024-01-12 - Email Geeks
Expert view
Expert from Email Geeks says that if a particular email is flagged as bulk but doesn't have the one-click unsubscribe, a GPT check might flag it.
2024-01-12 - Email Geeks
Key takeaways
Ensuring Sendlane's compliance with RFC 8058 for one-click unsubscribe is paramount for maintaining good email deliverability and respecting recipient preferences. While Sendlane should ideally implement this standard, it's your responsibility to verify it. Don't rely solely on basic support explanations; delve into the email headers to confirm the presence and proper configuration of the List-Unsubscribe and List-Unsubscribe-Post headers.
By understanding the technical aspects of RFC 8058 and actively monitoring your email deliverability, you can proactively address any compliance gaps. This proactive approach not only keeps you aligned with Google and Yahoo's requirements but also fosters a healthier email ecosystem, benefiting both senders and recipients alike.
Yahoo has placed a renewed focus on one-click unsubscribe functionality, specifically compliance with RFC 8058. This standard is crucial for ensuring recipients can easily opt out of unwanted emails, which in turn helps maintain a good sender reputation and improves email deliverability.
Sendlane's support suggests that a footer link suffices for RFC 8058 compliance, this indicates a misunderstanding. The standard specifically refers to headers. A support representative might not have the full technical knowledge of email deliverability requirements. It's crucial to escalate the issue to their technical or deliverability team to ensure they understand the specific nature of RFC 8058 and its implementation.
