Email health
Mailbox provider feedback loops (FBL)
Per-IP and per-domain complaint reports from major mailbox providers. The only direct signal that recipients are flagging your mail as spam — register or fly blind.
What it is
Industry-shared complaint reporting: Yahoo's Complaint Feedback Loop, Microsoft's SNDS + Junk Mail Reporting Program (JMRP), Google's Postmaster Tools, Comcast's FBL, etc. Each ships an ARF-formatted (RFC 5965) report when a recipient hits `Mark as Spam`, scoped to the IP or DKIM domain that signed up.
Why it matters
The bulk-sender requirements set a 0.30% complaint-rate ceiling but don't tell you when you cross it. FBLs and Postmaster Tools are the feedback channel — the difference between fixing a bad list segment in a day vs. a quarter of degraded deliverability.
Who it applies to
Any sender pushing meaningful volume to Yahoo, Microsoft, or Google inboxes.
How WQI scores it
Web Quality Index considers this standard satisfied when the supporting factor passes.
| # | Factor | Status |
|---|---|---|
| 80 | Email Service Provider (ESP) detected | planned |
0 of 1 supporting factors are currently collected. Sites where the remaining 1 haven't been measured will show as partial or unknown on this standard until the data lands.
Related standards
- See also
- Bulk-sender 2024 , DMARC
Other references
- tooling Microsoft SNDS + JMRP
- tooling Google Postmaster Tools
- rfc RFC 5965 — Abuse Reporting Format (ARF)