curl --request POST \
  --url https://api.coinbase.com/api/v3/brokerage/orders/close_position \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "client_order_id": "0000-00000-000000",
  "product_id": "BIT-28JUL23-CDE",
  "size": 3
}'

{
  "success": true,
  "success_response": {
    "order_id": "11111-00000-000000",
    "product_id": "BTC-USD",
    "side": "BUY",
    "client_order_id": "0000-00000-000000"
  },
  "error_response": {
    "error": "UNKNOWN_FAILURE_REASON",
    "message": "The order configuration was invalid",
    "error_details": "Market orders cannot be placed with empty order sizes",
    "preview_failure_reason": "UNKNOWN_PREVIEW_FAILURE_REASON",
    "new_order_failure_reason": "UNKNOWN_FAILURE_REASON"
  },
  "order_configuration": {
    "market_market_ioc": {
      "quote_size": "10.00",
      "base_size": "0.001"
    },
    "market_market_fok": {
      "quote_size": "10.00",
      "base_size": "0.001"
    },
    "sor_limit_ioc": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "limit_price": "10000.00"
    },
    "limit_limit_gtc": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "limit_price": "10000.00",
      "post_only": false
    },
    "limit_limit_gtd": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "limit_price": "10000.00",
      "end_time": "2021-05-31T09:59:59.000Z",
      "post_only": false
    },
    "limit_limit_fok": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "limit_price": "10000.00"
    },
    "twap_limit_gtd": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "start_time": "2021-05-31T07:59:59.000Z",
      "end_time": "2021-05-31T09:59:59.000Z",
      "limit_price": "10000.00",
      "number_buckets": "5",
      "bucket_size": "2.00",
      "bucket_duration": "300s"
    },
    "stop_limit_stop_limit_gtc": {
      "base_size": "0.001",
      "limit_price": "10000.00",
      "stop_price": "20000.00",
      "stop_direction": "20000.00"
    },
    "stop_limit_stop_limit_gtd": {
      "base_size": 0.001,
      "limit_price": "10000.00",
      "stop_price": "20000.00",
      "end_time": "2021-05-31T09:59:59.000Z",
      "stop_direction": "20000.00"
    },
    "trigger_bracket_gtc": {
      "base_size": 0.001,
      "limit_price": "10000.00",
      "stop_trigger_price": "20000.00"
    },
    "trigger_bracket_gtd": {
      "base_size": 0.001,
      "limit_price": "10000.00",
      "stop_trigger_price": "20000.00",
      "end_time": "2021-05-31T09:59:59.000Z"
    }
  }
}