Get a range of individuals for your targeting and what bids to make to reach that target group with the /reachestimate
API. You can call this API in one of these ways:
curl -G \
--data-urlencode 'targeting_spec={
"geo_locations": {"countries":["US","GB"]},
"publisher_platforms": ["instagram"],
"user_os": ["iOS"]
}' \
-d 'optimize_for=IMPRESSIONS' \
-d 'access_token=<ACCESS_TOKEN>' \
https://graph.facebook.com/v21.0
/act_<AD_ACCOUNT_ID>/reachestimate