Major email providers like Gmail, Yahoo, and Outlook have made it mandatory for bulk and marketing emails to include a List-Unsubscribe header. This helps users easily opt out of emails by showing a native "Unsubscribe" option directly in their inbox interface—improving user experience and reducing spam complaints.
Before You Begin
You don’t need to take any additional steps to create a List-Unsubscribe header in SendX.
✅ SendX automatically adds List-Unsubscribe headers to all outgoing marketing emails by default.
However, it’s important to understand how email service providers (ESPs) interpret and display these headers, as results may vary based on your sending behavior and domain reputation.
Step-by-Step Explanation
1. How It Works in SendX
Every marketing or bulk email sent via SendX includes a List-Unsubscribe header.
This header provides email providers with both a mailto link and an HTTP link for unsubscribing.
These links allow email clients to extract the unsubscribe option and display it natively in the user interface.
2. How Different ESPs Display the Unsubscribe Option
Gmail: Shows the native “Unsubscribe” link only if your domain has a good reputation and consistent sending behavior.
Yahoo: Follows a similar reputation-based approach to Gmail.
Microsoft (Outlook/Hotmail): Tends to show the native unsubscribe option more frequently, even for newer or less-established domains.
3. How to Verify the Header
You can inspect your email headers using:
Gmail: Open an email > click the 3-dot menu > "Show original"
MXToolbox Header Analyzer: Paste your full email header to analyze all included fields, including
List-Unsubscribe
Tips & Best Practices
✅ Maintain a clean list: Always send to opted-in subscribers
📈 Monitor domain reputation: Using tools like Google Postmaster Tools
📬 Authenticate your domain: Ensure DKIM, SPF, and DMARC are properly set up
💡 Avoid spammy content or high complaint rates, which can harm reputation and suppress the UI-based unsubscribe option
Conclusion
SendX is fully compliant with the latest List-Unsubscribe requirements and automatically adds the necessary headers to your emails. However, whether the unsubscribe link appears in Gmail or Outlook's UI depends on your domain’s reputation and sending practices.
For more detailed reading, here are some helpful resources:
Need help reviewing your email headers or improving inboxing? Reach out to the SendX support team—we’re here to help!