Complaints are the strongest negative signal. FBLs let you suppress complainers immediately and detect problem campaigns before reputation collapses.
Mistake 1: Registering but never processing the reports#
Why it hurts: this undermines complaint feedback loops at the point where mailbox providers make their decision, and it is rarely surfaced by your own tooling until placement drops.
Fix: Register your sending IPs and domains with each provider's FBL.
Mistake 2: Gmail has no traditional FBL; use Postmaster Tools spam rate instead#
Why it hurts: this undermines complaint feedback loops at the point where mailbox providers make their decision, and it is rarely surfaced by your own tooling until placement drops.
Fix: Route FBL messages to an automated parser.
Frequently asked questions#
Does Gmail offer a feedback loop?
Only an aggregate one via Postmaster Tools using the Feedback-ID header. Gmail does not return individual complaints.