How do I test and validate one-click unsubscribe functionality in Salesforce Marketing Cloud (SFMC)?

Summary

Testing and validating one-click unsubscribe functionality in SFMC is a multi-faceted process. It begins with ensuring adherence to RFC8058 standards, which mandate the presence of a correctly formatted `List-Unsubscribe` header (containing both mailto: and URL options) in commercial emails. While SFMC automatically includes these headers, manual verification is crucial. This involves employing testing tools like aboutmy.email, curl, and Postman to simulate HTTP POST requests to the unsubscribe URL and confirming subscriber status changes within SFMC. Remember to disregard the HTML response from curl tests, focusing solely on subscriber status. Gmail's display of the unsubscribe button can vary based on sender reputation and email volume, necessitating testing across multiple email clients (Gmail, Outlook, Yahoo). The process for one-click unsubscribe (via POST) differs from standard unsubscribe (via URL in a browser). If issues persist despite thorough testing, contacting SFMC support is recommended.

Key findings

  • RFC8058 Compliance: Adherence to RFC8058 is essential, requiring a correctly formatted `List-Unsubscribe` header.
  • Automated Inclusion: SFMC automatically includes one-click unsubscribe headers, but verification is still necessary.
  • Testing Tool Variety: Utilize tools such as aboutmy.email, curl, and Postman for comprehensive testing.
  • HTTP Post Emphasis: One-click unsubscribe requires sending a POST request.
  • Subscriber Status Focus: Focus on verifying the subscriber status change in SFMC, rather than the HTML response during testing.
  • Client Variability: Test across multiple email clients due to display variations.

Key considerations

  • Reputation Impact: Sender reputation and email volume can influence unsubscribe button visibility in Gmail.
  • Distinct Unsubscribe Methods: One-click (POST) and standard (URL) unsubscribe processes differ.
  • External Resources: Leverage resources like the Spam Resource webinar for a deeper understanding of list-unsubscribe.
  • Header Verification: Manually verify the `List-Unsubscribe` header to ensure it's present and correctly formatted, containing both mailto: and URL options.
  • SFMC Support: Contact SFMC support for unresolved issues following testing.

What email marketers say
9Marketer opinions

Testing one-click unsubscribe functionality in SFMC involves several steps: verifying header configuration, using tools like aboutmy.email or Postman to simulate HTTP POST requests, checking subscriber status in SFMC after triggering the unsubscribe, and testing across different email clients. If issues persist, sender reputation and contacting SFMC support are important considerations.

Key opinions

  • Header Configuration: Ensure the List-Unsubscribe header is correctly configured with a valid URL.
  • Testing Tools: Use tools like aboutmy.email, curl, or Postman to simulate HTTP POST requests to the unsubscribe URL.
  • Subscriber Status Verification: After triggering the unsubscribe, verify that the subscriber status is updated correctly in SFMC.
  • Client Variability: Test across multiple email clients (Gmail, Outlook, Yahoo) as the display of the one-click unsubscribe button can vary.

Key considerations

  • Sender Reputation: If the unsubscribe button is not showing in Gmail, consider improving your sender reputation and increasing email volume.
  • SFMC Support: If initial tests pass but the functionality still doesn't work as expected, contact SFMC support for further assistance.
  • Backend Verification: Check the backend systems (SFMC) to confirm the subscriber has been successfully unsubscribed.
Marketer view

Email marketer from EmailGeeks Slack Channel recommends using aboutmy.email to check if one-click unsubscribe is valid. Also suggests using curl to test and verify if the unsubscribe 'worked' in the internal systems.

May 2023 - EmailGeeks Slack Channel
Marketer view

Email marketer from Email Marketing Tips states that if the one-click unsubscribe button isn't showing in Gmail, it might be related to a low sender reputation or insufficient email volume, advising focusing on improving sender reputation.

January 2025 - Email Marketing Tips
Marketer view

Email marketer from Litmus notes that not all email clients display the one-click unsubscribe button, so testing across multiple clients (Gmail, Outlook, Yahoo) is crucial to ensure it works as expected for a wide range of users.

December 2022 - Litmus
Marketer view

Email marketer from Email Geeks suggests using tools like Postman or other HTTP clients to test the unsubscribe URLs and check the backend.

October 2021 - Email Geeks
Marketer view

Email marketer from Salesforce Trailblazer Community mentions that if the one-click unsubscribe passes initial tests but still doesn't function as expected, the next step is to contact SFMC support to investigate potential configuration issues or bugs.

November 2023 - Salesforce Trailblazer Community
Marketer view

Email marketer from Reddit suggests after triggering one-click unsubscribe, verify the subscriber status within SFMC to confirm the unsubscribe was successful and the subscriber is no longer active.

November 2021 - Reddit
Marketer view

Email marketer from Stack Overflow suggests checking the email headers to ensure the List-Unsubscribe header is correctly configured and that the URL is valid.

March 2021 - Stack Overflow
Marketer view

Email marketer from Email on Acid advises using seed lists to send test emails and then manually triggering the one-click unsubscribe to see if it functions correctly and updates the subscriber status in SFMC.

September 2023 - Email on Acid
Marketer view

Email marketer from MarketingProfs suggests using Postman (or similar tools) to send a POST request to the unsubscribe endpoint and then checking the backend systems (SFMC) to confirm that the subscriber has been successfully unsubscribed.

April 2024 - MarketingProfs

What the experts say
9Expert opinions

Validating one-click unsubscribe in SFMC requires checking for the correct List-Unsubscribe headers (as per RFC8058), testing with tools like aboutmy.email and curl, and verifying subscriber status. Gmail's display can vary based on sender reputation and volume. Curl tests should focus on the subscriber status change, not the HTML response. Contact SFMC support if issues persist after these tests. The process for one-click unsubscribe (via POST) differs from standard unsubscribe (via URL in browser).

Key opinions

  • RFC8058 Compliance: One-click unsubscribe links must adhere to RFC8058 standards and be included as headers.
  • Testing Methods: Use aboutmy.email for initial checks and curl for detailed testing, specifically ensuring the List-Unsubscribe header is correctly set to 'One-Click' when using curl.
  • Subscriber Status Verification: Always verify the subscriber status change in SFMC after triggering the unsubscribe, as the curl response is irrelevant.
  • Gmail Display Variance: The display of the unsubscribe button in Gmail can depend on sender reputation and email volume.
  • Unsubscribe Mechanisms: One-click unsubscribe requires a POST request, while standard unsubscribe involves accessing a URL in a browser.

Key considerations

  • SFMC Configuration: Although one-click unsubscribe is automatic in SFMC, contact SFMC support if issues persist after thorough testing.
  • Testing scope: Test both one-click unsubscribe (curl) and standard unsubscribe (browser URL) to ensure both work as expected.
  • Debugging: Spam Resource webinar offers a crash course on testing POST and HTTP requests.
Expert view

Expert from Email Geeks suggests using curl to test one-click unsubscribe functionality, referencing a Word to the Wise article for details. Emphasizes ensuring the RFC8058 unsubscribe is valid, not just the in-body unsubscribe.

September 2024 - Email Geeks
Expert view

Expert from Email Geeks explains that one-click unsubscribe links need to be headers as specified in RFC8058. Recommends inspecting the actual email sent to see if the headers are present and using aboutmy.email to check.

June 2023 - Email Geeks
Expert view

Expert from Email Geeks refers to Salesforce documentation stating one-click unsubscribe is automatic and required for all commercial sends. Recommends contacting SFMC support if issues persist after passing tests.

January 2025 - Email Geeks
Expert view

Expert from Email Geeks shares that a correctly formatted HTTP POST request with curl should trigger the list-unsub-post. If the subscriber status isn't updating after a successful curl request, suggests contacting SFMC support.

December 2022 - Email Geeks
Expert view

Expert from Email Geeks explains that Gmail doesn't always show the unsubscribe button due to reputation or volume. Recommends testing with tools like aboutmy.email and Outlook.com.

October 2021 - Email Geeks
Expert view

Expert from Spam Resource responds with webinar crash course on list-unsubscribe. Covers testing POST requests, HTTP request, and general list unsubscribing processes. The webinar can help when diagnosing if it is working correctly.

December 2022 - Spam Resource
Expert view

Expert from Email Geeks clarifies that curl is used to check one-click unsubscribe and going to the URL in the browser checks non-one-click unsubscribe. A script doing a POST should unsubscribe and done. A person loading the URL, should see a landing page / profile page.

December 2023 - Email Geeks
Expert view

Expert from Word to the Wise explains that testing one-click unsubscribe involves using curl to send a POST request to the unsubscribe URL. The article details the necessary components of the request, emphasizing the importance of including the `List-Unsubscribe` header set to `One-Click`. It also suggests verifying that the subscriber's status is correctly updated in the system after the curl command is executed.

July 2022 - Word to the Wise
Expert view

Expert from Email Geeks advises to ignore the HTML response from a curl test, focus on checking the subscriber status internally to ensure the unsubscribe worked.

November 2024 - Email Geeks

What the documentation says
5Technical articles

Validating one-click unsubscribe in SFMC involves ensuring the correct List-Unsubscribe header format (as per RFC8058), which should include both mailto: and URL options. SFMC automatically includes these headers, but verification is necessary. Testing includes simulating HTTP POST requests using tools like curl and confirming subscriber status changes in SFMC. If issues persist, consulting SFMC Support is advised.

Key findings

  • Automatic Inclusion: SFMC automatically includes one-click unsubscribe headers in commercial emails.
  • RFC8058 Standard: Compliance with RFC8058 requires a List-Unsubscribe header and proper handling of HTTP POST requests.
  • Header Format: The List-Unsubscribe header should include both mailto: and URL options for compatibility.
  • Testing with Curl: Curl can simulate HTTP POST requests to the unsubscribe URL for testing purposes.
  • Status Verification: Verify subscriber status changes in SFMC after testing the unsubscribe functionality.

Key considerations

  • SFMC Support: Consult SFMC Support for unresolved issues after initial checks and testing.
  • Detailed Instructions: Refer to documentation from SendGrid and other sources for detailed instructions on correctly formatting the List-Unsubscribe header.
Technical article

Documentation from Salesforce Help explains that Salesforce Marketing Cloud automatically includes one-click unsubscribe headers in commercial emails. It advises checking with SFMC Support for any remaining questions after confirming the feature is enabled.

July 2024 - Salesforce Help
Technical article

Documentation from SparkPost explains how to use curl to simulate an HTTP POST request to the unsubscribe URL, checking for a successful response and verifying the subscriber’s status change in SFMC.

December 2022 - SparkPost
Technical article

Documentation from datatracker.ietf.org details the RFC8058 standard which requires List-Unsubscribe header and the handling of HTTP POST requests for one-click unsubscribe functionality.

August 2021 - datatracker.ietf.org
Technical article

Documentation from SendGrid explains the importance of correctly formatting the List-Unsubscribe header with both the mailto: and HTTP URL, providing detailed instructions on how to set this up to ensure compatibility with various email clients.

October 2022 - SendGrid
Technical article

Documentation from Oracle Help Center highlights that the List-Unsubscribe header should include both a mailto: and a URL option to ensure compatibility with different email clients and provide a fallback mechanism.

July 2024 - Oracle Help Center