Q: My network offers both pre-bid and post-bid fraud filtering. Which one actually protects my budget?

Q: My network offers both pre-bid and post-bid fraud filtering. Which one actually protects my budget?

A: Different jobs. Think of pre-bid as the bouncer and post-bid as the auditor.

Pre-bid filtering blocks a placement or impression before you pay for it — it reads signals on the request (suspicious domain, declared bot, blacklisted app) and refuses the bid. It saves spend in real time, but it has milliseconds to decide, so it only catches what's obvious upfront.

Post-bid (or post-click) analysis runs after the event, with full session data — dwell time, conversion patterns, downstream behavior. It catches sophisticated fraud pre-bid can't see, but the money's already spent. Its value is the refund claim and the optimization for next time.

How to use them:
— Pre-bid for waste prevention on programmatic and display.
— Post-bid for chargeback defense and supply-source scoring.
— Reconcile the two weekly: anything post-bid catches that pre-bid missed should become a new pre-bid rule.

Short version: pre-bid saves money now but sees little; post-bid sees everything but spends first. Run both, feed one into the other.

Still stuck? Drop your case in the comments.