Yahoo Complaint Feedback Loop (CFL)

The Complaint Feedback Loop (CFL) is Yahoo's service that sends the sender a report — in ARF (Abuse Reporting Format) — each time a Yahoo user marks one of the sender's messages as spam. Its purpose is to let senders suppress complainers from further campaigns and adjust targeting/frequency, since spam votes directly damage sender reputation and count toward Yahoo's 0.3% complaint threshold (see Yahoo Sender Requirements).

Key properties

Property	Value
Basis	Domain-based, DKIM-only — only DKIM-signed mail is supported; DKIM is how Yahoo determines the actual responsible sender
IP-based FBL	Not offered — Yahoo no longer supports IP or CIDR-based CFL reporting
Report format	ARF
Coverage	All Yahoo-hosted consumer domains, including AOL (thousands of hosted domains)
Who should enroll	Bulk email senders; ESPs typically enroll DKIM domains on behalf of clients

Enrollment (via Sender Hub)

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

Notes:

• Enrollments made through Yahoo's old (pre-Sender Hub) form did not carry over — re-enrollment through Sender Hub was required; ARF reports for legacy 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 the same verified address can be reused for additional domain enrollments.
• Subdomains are not blanket-enrolled by enrolling the organizational domain: ARF reports are sent for the enrolled DKIM domains that match the signature on the complained-about message. Enroll each signing domain.
• Verify enrollment status, edit, or delete enrollments under Manage Services → Complaint Feedback Loop in your Sender Hub profile.

Report mechanics

• All reports use the Abuse Reporting Format (ARF) and contain three minimum MIME parts: a plain-text part, MIME-formatted machine-readable metadata, and the original message headers.
• Report messages arrive with:
  • From header display name: "Yahoo! Mail AntiSpam Feedback"
  • SMTP sender: feedback@arf.mail.yahoo.com
  • DKIM-signed with domain arf.mail.yahoo.com (verify the signature before trusting/automating on reports)
• With multiple DKIM signatures on a message, Yahoo evaluates all of them for CFL fulfillment (as well as DMARC alignment and reputation).

Operational use

• Automate suppression: parse incoming ARF reports and immediately unsubscribe/suppress the complaining recipient. Continuing to mail complainers compounds reputation damage.
• Monitor complaint rate: CFL volume relative to Yahoo-delivered volume is the practical way to watch your standing against the 0.3% threshold; the Performance Feeds complaints metric provides an aggregate view.
• Diagnose segments: spikes in ARF reports after a content, frequency, or audience change identify the offending campaign or segment.

Related articles

• Yahoo Sender Requirements — the 0.3% complaint threshold this program helps you manage.
• Yahoo Deliverability Performance Feeds — aggregate complaint and placement metrics.
• Foundations of Email Deliverability — how complaints feed reputation.