How do aggregated FBLs (like Microsoft’s ARF) differ from individual ones?

If you've ever wondered why some FBL reports land in your inbox the moment a subscriber hits the spam button, while others show up as a tidy weekly summary, that's the individual vs. aggregated distinction at work.

Individual FBLs fire a separate feedback loop report for each complaint as it happens. Someone marks your email as spam at 2pm, and you get a notification by 2:05pm. That's fast. It's also noisy if you're sending at volume, because each complaint is its own message in your processing queue.

Aggregated FBLs collect complaints over a defined window (daily or weekly) and bundle them into a single report. Instead of 200 individual notifications, you get one file with 200 rows. The trade-off is obvious: you lose real-time visibility, but your system has far less to process and the data is easier to analyze in bulk.

Now, about Outlook's JMRP: this is where a lot of people get confused. Microsoft's program sends individual ARF (Abuse Reporting Format) reports by default, not aggregated ones. Each complaint generates its own ARF-formatted notification. Some high-volume senders do receive batched versions, but that's not how the program works out of the box. So if you're expecting one tidy summary from JMRP, you'll be surprised by the volume.

Which format is better for suppression depends on your setup. Individual reports let you suppress a complaining address almost instantly, which matters if you're in a regulated industry or running a high-frequency program where a few bad addresses can snowball quickly. Aggregated reports are easier to route into a batch suppression workflow, especially if your tech stack processes files rather than real-time API calls.

For most senders, here's a practical way to think about it. If you send fewer than 50,000 emails a day, individual FBL reports are manageable and give you the fastest response time. If you're pushing millions per day, aggregated reporting makes more operational sense, as long as your suppression job runs at least daily and not just weekly.

One thing both formats share: neither does anything useful if you're not acting on the data. Getting the report is step one. Automatically suppressing the complaining address before your next send is what actually protects your sender reputation. The format is secondary to the workflow you build around it.

If you're not sure whether your FBL integration is actually working the way you think it is, our SOS hotline is free and we're happy to walk through your setup with you.