What is Feedback Loop?
A feedback loop (FBL) is a service provided by inbox providers that notifies you when recipients mark your emails as spam, allowing you to remove complainers from your list.
A feedback loop (FBL) is a reporting mechanism where inbox providers (like Yahoo, Outlook, and AOL) send you notifications when recipients click "Mark as Spam" or "Report Junk" on your emails. These reports typically arrive in ARF (Abuse Reporting Format) and contain the email address of the person who complained.
Feedback loops serve two purposes:
1. **For senders**: You learn who complained so you can remove them from your list and stop sending them email. This protects your reputation.
2. **For inbox providers**: If a sender ignores complaints and keeps sending to people who marked them as spam, the provider knows they're dealing with a bad actor.
To receive FBL reports, you must register with each inbox provider's program separately. You'll need to verify domain ownership and set up a dedicated email address to receive reports.
Important: Gmail does not operate a traditional feedback loop. Instead, they provide aggregate spam complaint data through Google Postmaster Tools—you can see complaint rates but not individual complainers.
Why Feedback Loop Matters
Every spam complaint hurts your sender reputation. Keep complaint rates above 0.1% and inbox providers will start filtering your emails to spam for everyone—not just the people who complained. Feedback loops let you identify and remove complainers before the damage compounds. They also reveal content problems: if one campaign generates way more complaints than usual, you know something about that email triggered recipients. FBL data is essential for maintaining long-term deliverability.
How Ark Handles Feedback Loop
Ark automatically processes feedback loop reports from major inbox providers. When someone marks your email as spam, we add them to your suppression list immediately—you'll never accidentally email them again. Our dashboard shows complaint rates over time, and our webhooks notify you of complaints in real-time so you can track which campaigns generate the most issues.
Frequently Asked Questions
Does Gmail have a feedback loop?
Not a traditional one. Gmail doesn't send individual complaint reports. Instead, use Google Postmaster Tools to see aggregate spam complaint rates for your domain. You can see if your complaint rate is problematic but won't know exactly which recipients complained.
What complaint rate is acceptable?
Keep spam complaints below 0.1% (1 complaint per 1,000 emails). Google recommends staying below 0.1% and never exceeding 0.3%. Rates above 0.1% signal that something is wrong with your sending practices and will hurt deliverability.
Which inbox providers offer feedback loops?
Major FBL programs include: Microsoft (Outlook, Hotmail), Yahoo, AOL, Comcast, and others. Each requires separate registration. Gmail provides aggregate data through Postmaster Tools instead of a traditional FBL.
Why would someone mark a legitimate email as spam?
Often it's easier than finding the unsubscribe link—especially on mobile. Sometimes users forget they signed up, don't recognize your sender name, or receive too many emails. This is why visible unsubscribe links and recognizable sender names matter.
How do I register for feedback loops?
Each provider has their own registration process. Generally, you'll need to: verify domain ownership, prove you're a legitimate sender, and provide an email address to receive reports. Your ESP may handle FBL registration for their IP ranges.
Should I email someone who complained to apologize?
Absolutely not. Emailing someone who marked you as spam will make things worse. They don't want your emails—respect that. Remove them from your list permanently and move on.
Related Terms
Email Deliverability
Email deliverability is the ability to successfully deliver emails to recipients' inboxes rather tha...
Suppression List
A suppression list is a database of email addresses that should not receive emails, including bounce...
Spam Trap
A spam trap is an email address used to identify spammers, either recycled from abandoned accounts o...
Hard Bounce
A hard bounce is a permanent email delivery failure that occurs when the recipient address is invali...
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