How should one-click unsubscribe links handle GET vs POST requests?

Key findings

• RFC 8058 specification: RFC 8058 defines a true one-click unsubscribe mechanism primarily through HTTPS POST requests, designed for automated processing without user interaction.
• GET request purpose: GET requests to unsubscribe URLs should ideally display a confirmation page, giving the user an option to confirm their unsubscribe intent, rather than immediately opting them out. This prevents accidental unsubscribes from bot clicks or security scans.
• POST request purpose: POST requests are intended for the direct, automated processing of unsubscribe requests, aligning with the one-click unsubscribe requirement.
• Compliance implications: Failure to differentiate between GET and POST requests can lead to high, unintended unsubscribe rates, affecting sender reputation and potentially causing your emails to be flagged as spam.

Key considerations

• Server configuration: Ensure your server is configured to differentiate between GET and POST requests for unsubscribe links, preventing direct unsubscribes via GET.
• Confirmation page: For GET requests, present a clear confirmation page that requires user action to complete the unsubscribe process. This aligns with best practices for subscriber management.
• Security and bots: Be aware that email clients and security scanners may perform GET requests to validate links. If these lead to immediate unsubscribes, it poses risks to your subscriber data.
• Testing: Regularly test your unsubscribe links to ensure they behave as expected for both GET and POST requests. For detailed information, refer to Mailmodo's guide on RFC 8058.

Key opinions

• Accidental unsubscribes: Many marketers report issues with automated systems, like Microsoft's security checks, inadvertently triggering one-click unsubscribes via GET requests.
• Confirmation flow importance: There's a strong preference for GET requests to lead to a confirmation page rather than a direct unsubscribe, ensuring the user truly intends to opt out. This is a key aspect of unsubscribe link best practices.
• Distinguishing request types: Marketers recognize the necessity of differentiating between GET (for validation/display) and POST (for actual unsubscribe) to prevent unintended list decay.
• Compliance pressure: The new Google and Yahoo requirements for one-click unsubscribe are driving renewed attention to the technical implementation details.

Key considerations

• Debugging unintended unsubscribes: Investigate if direct GET requests to your unsubscribe URLs are leading to immediate opt-outs, as this indicates a configuration issue on your end.
• User experience: While RFC 8058 pushes for one-click POST, ensure that any GET requests still provide a clear and user-friendly pathway to unsubscribe if a confirmation is needed.
• Monitoring: Keep a close eye on your unsubscribe rates and source IPs to identify any unusual patterns that might indicate automated unsubscribes. For more details, consult Mailgun's RFC 8058 guide.
• Technical alignment: Work with your technical team to ensure your unsubscribe links are correctly implemented according to RFC 8058 for both GET and POST methods.

Key opinions

• Distinct function: Experts agree that GET requests are for displaying information or confirmation pages, while POST requests are for performing an action like unsubscribing.
• Bug indication: An immediate unsubscribe triggered by a GET request signifies a critical bug in the server-side implementation.
• RFC 8058 adherence: Strictly following RFC 8058 dictates that actual unsubscribe actions should only occur via POST, safeguarding against automated unsubscriptions. This is crucial for Yahoo and Google's new requirements.
• Impact of automated checks: Automated email client and security scans, which often use GET requests, can unintentionally unsubscribe users if the system is misconfigured.

Key considerations

• Validate server logic: Ensure your server-side logic correctly distinguishes between GET and POST requests for unsubscribe links, processing them according to standard protocols.
• Prevent unintended unsubscribes: Only process an actual unsubscribe request when a POST request is received for the `List-Unsubscribe` header. This helps prevent accidental unsubscriptions.
• Monitor for anomalies: Continuously monitor unsubscribe logs for unusual activity, such as bulk unsubscribes from unexpected IP ranges or those triggered by GET requests. For further reading, see AhaSend's implementation guide.
• Regular audits: Conduct regular audits of your unsubscribe mechanism to ensure it remains compliant and robust against automated interactions.

Key findings

• RFC 8058 definition: RFC 8058 outlines the one-click unsubscribe standard via HTTP POST requests to the `List-Unsubscribe` header URI, making the process seamless for users.
• GET request behavior: Documentation generally recommends that GET requests to the unsubscribe URL should display a landing page where the user can confirm their unsubscription, rather than performing an immediate opt-out.
• POST request behavior: A POST request to the specified URI in the `List-Unsubscribe-Post` header should trigger the unsubscription process directly and automatically, without further user interaction.
• Header inclusion: For full compliance and to support one-click functionality, both the `List-Unsubscribe` and `List-Unsubscribe-Post` headers should be included in email messages.

Key considerations

• Security and automation: The POST method is highlighted as more secure, explicitly designed for automated processing triggered by email clients, minimizing risks of bot-driven unsubscribes.
• RFC compliance: Adherence to RFC 8058 is crucial for meeting modern mailbox provider requirements, which increasingly mandate proper one-click unsubscribe implementation.
• Unsubscribe processing time: Some documentation suggests that the unsubscribe request triggered by a POST should be processed within 48 hours to ensure a timely opt-out. For deeper technical insights, refer to Customer.io's documentation on custom unsubscribe links.
• Header structure: Pay attention to the specific format and content of the `List-Unsubscribe` and `List-Unsubscribe-Post` headers to ensure they are correctly parsed by email clients.