The Cloud Billing Budget API stores Cloud Billing budgets, which define a budget plan and the rules to execute as spend is tracked against that plan.
curl \
-H "Authorization: Bearer $ACCESS_TOKEN" \
https://billingbudgets.googleapis.com/v1beta1/{name}curl \
-H "Authorization: Bearer $ACCESS_TOKEN" \
https://billingbudgets.googleapis.com/v1beta1/{parent}/budgets