Targeting
Eligibility rules for a campaign: geo, environment, inventory source, segments, and related keys. Different from bid modifiers and from QPS filters.
Targeting is the eligibility expression a campaign points at: countries, web versus app, inventory sources, segments, ads.txt class when set, and other keys the product compiles. If a request does not match, the campaign should not bid.
It is not a bid modifier. Modifiers change price on a match and use a wider key list. It is not a QPS template. Templates decide which auctions consume the exchange account's QPS before targeting ever runs.
Create targeting through the public path (MCP create_targeting or POST /targeting). Discover segment ids before you attach them. Do not invent exchange expression IDs.
An unset inventory-source list is unrestricted remnant. Placement and site excludes are direct keys. Domain excludes still need list objects. Empty allowlists that would match nothing are refused.
Name the campaign so the targeting token is readable. See the naming sheet. After launch, change targeting once per day if you want to read the result.