curl --request GET \
  --url https://api.barker.money/api/partner/products/{slug}/yield-calc \
  --header 'X-Api-Key: <api-key>'

{
  "success": true,
  "data": {
    "principal": "10000.0",
    "annual_yield": "456.78",
    "monthly_yield": "38.07",
    "net_apy_for_user": "0.0457"
  }
}