Yahoo Complaint Feedback Loop (CFL)

If you send mail to Yahoo users, you can receive a report each time one of them marks your message as spam. Yahoo's Complaint Feedback Loop (CFL) sends these reports in ARF (Abuse Reporting Format).

The reports let you suppress complainers from further campaigns and adjust your targeting and frequency. This matters because spam votes directly damage sender reputation, and count toward Yahoo's 0.3% complaint threshold (see Yahoo Sender Requirements).

Key properties

Enrollment (via Sender Hub)

1. Create your Sender profile on Yahoo Sender Hub (senders.yahooinc.com).
2. Add and verify your domains: the DKIM d= domains you sign with.
3. Enroll each domain in the CFL.

Notes:

• Enrollments made through Yahoo's old form, from before Sender Hub, did not carry over. You had to enroll again through Sender Hub. ARF reports for old enrollments stopped on August 1, 2024, with no grace period.
• The reporting address can be any email address you control. Ownership is verified during enrollment, and you can reuse the same verified address to enroll more domains.
• Enrolling the organizational domain does not enroll all its subdomains. ARF reports are sent for the enrolled DKIM domains that match the signature on the message that received the complaint. Enroll each signing domain.
• To check the status of enrollments, edit them or delete them, go to Manage Services, then Complaint Feedback Loop, in your Sender Hub profile.

Report mechanics

• All reports use the Abuse Reporting Format (ARF) and contain at least three MIME parts: a plain-text part, machine-readable metadata in MIME format, and the headers of the original message.
• Report messages arrive with:
  • From header display name: "Yahoo! Mail AntiSpam Feedback"
  • SMTP sender: feedback@arf.mail.yahoo.com
  • A DKIM signature with the domain arf.mail.yahoo.com (verify the signature before you trust the reports or automate actions on them)
• When a message has several DKIM signatures, Yahoo evaluates all of them for the CFL (and also for DMARC alignment and reputation).

Operational use

• Automate suppression. Parse incoming ARF reports, and immediately unsubscribe or suppress the recipient who complained. Continuing to mail people who complained adds to the reputation damage.
• Monitor the complaint rate. Comparing CFL volume with the volume delivered to Yahoo is the practical way to track your position against the 0.3% threshold. The complaints metric in the Performance Feeds gives an aggregate view.
• Diagnose segments. A spike in ARF reports after a change in content, frequency or audience identifies the campaign or segment at fault.

Related articles

• Yahoo Sender Requirements, including the 0.3% complaint threshold
• Yahoo Deliverability Performance Feeds, for aggregate complaint and placement metrics
• Foundations of Email Deliverability, on how complaints affect reputation