The following overrides are available.
Override bidding strategies
A bid strategy can only be set at the campaign level. So for example, if a
campaign has already been assigned a TARGET_ROAS
strategy, setting TARGET_CPA
fields in one of its ad groups will have no effect.
Similarly, setting bids manually will have no effect if you are using a
campaign-level bid strategy that doesn't support them. For example, if your
campaign uses TARGET_ROAS as a standard bidding strategy, and you set max CPC
values for individual keywords in that campaign, the keyword-level bids will be
ignored without errors. If you were to switch to manual bidding, the
keyword-level bids would then take effect. Read more in the
Help Center.
Override Target ROAS at the ad group level
The target_roas field of a
TargetRoas bidding scheme, or a
MaximizeConversionValue with its
target_roas field set,
can be overridden at the ad group level by setting the ad group's
target_roas field. The other fields of
the bidding scheme cannot be overridden.
To remove an override, unset target_roas
of the ad group by sending a mutate request with an empty field value but still
supplying the path in a field mask. Attempting to override the target_roas field of a
TargetRoas scheme associated to a portfolio
strategy will result in an error.
You can retrieve the effective target_roas value of an ad group with the
effective_target_roas field and
its source with the
effective_target_roas_source
field.
Override Target CPA at the ad group level
The target_cpa_micros field of a
TargetCpa bidding scheme, or a
MaximizeConversions with its
target_cpa_micros field
set, can be overridden at the ad group level by setting the ad group's
target_cpa_micros field. The other
fields of the bidding scheme cannot be overridden.
To remove an override, unset
target_cpa_micros of the ad group
by sending a mutate request with an empty field value but still supplying the
path in a field mask.
You can retrieve the effective value of target_cpa_micros for an ad group from
the
effective_target_cpa_micros
field and its source from the
effective_target_cpa_source
field.