How are ARF reports different from FBL reports?
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Here's the confusion most senders hit: FBL and ARF get mentioned together so often that they sound like two names for the same thing. They're not.
ARF (Abuse Reporting Format) is a standardized format for packaging complaint data. Think of it as the agreed-upon structure for how an abuse report is written, what fields it includes, and how the original message is attached. It's a format spec, like how a PDF is a format spec for documents.
FBL (Feedback Loop) is a service that mailbox providers run to notify senders when a recipient marks their email as spam. Yahoo Mail and AOL Mail operate FBLs that senders can register for. When someone hits "This is spam," you get notified. The notification arrives in ARF format.
So ARF is the envelope. FBL is the postal service that uses that envelope.
ARF isn't exclusive to FBLs, though. Any system that wants to report abuse in a standardized, machine-readable way can use ARF. Network abuse teams, hosting providers, and anti-spam organizations all use ARF-formatted reports to pass complaint data between systems, with no FBL involved at all.
What this means for you as a sender:
- You register for FBL programs at the mailbox providers that offer them. You don't "register for ARF" because it's a format, not a service.
- When FBL reports arrive in your inbox (or your ESP's complaint processing pipeline), they're formatted in ARF. That's what makes them parseable and actionable automatically.
- If you get an abuse report from somewhere other than an FBL, it may also be in ARF format. Same structure, different source.
The practical priority is FBL registration. That's the action item. ARF is the format those reports come in, and your ESP likely handles the parsing already. (Of course, if you're sending through your own infrastructure, you'll want to make sure your abuse@ address actually processes incoming ARF reports rather than just collecting dust.)
Not sure how to handle the complaints once they arrive? That's the next piece worth reading.
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