Q: Should I run my traffic sources on an allowlist or a blocklist?

Q: Should I run my traffic sources on an allowlist or a blocklist?

A: It's a trade between coverage and safety, and your volume decides.

A blocklist (deny known-bad, allow everything else) gives you maximum reach — you only lose the sources you've specifically caught. The catch: you're always one step behind. New bad source, fresh proxy pool, new placement ID — it sails through until you notice and add it.

An allowlist (allow only vetted sources, deny everything else) flips the risk. Nothing new touches you until you approve it. Bulletproof for fraud, brutal for scaling — and a maintenance burden.

When each fits:
— High-trust, low-volume, high-payout (finance leads, regulated offers): allowlist. You'd rather miss volume than pay fraud.
— Broad performance campaigns chasing scale: blocklist, with aggressive monitoring.
— Best of both: allowlist at the publisher/placement level, blocklist at the IP/device level underneath.

Short version: blocklist for reach with vigilance, allowlist for safety with effort. High-value verticals lean allowlist; scale plays lean blocklist.

Still stuck? Drop your case in the comments.