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
}
'

import requests

url = "https://api.coinbase.com/api/v3/brokerage/orders/close_position"

payload = {
    "client_order_id": "0000-00000-000000",
    "product_id": "BIT-28JUL23-CDE",
    "size": 3
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({client_order_id: '0000-00000-000000', product_id: 'BIT-28JUL23-CDE', size: 3})
};

fetch('https://api.coinbase.com/api/v3/brokerage/orders/close_position', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.coinbase.com/api/v3/brokerage/orders/close_position",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'client_order_id' => '0000-00000-000000',
    'product_id' => 'BIT-28JUL23-CDE',
    'size' => 3
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.coinbase.com/api/v3/brokerage/orders/close_position"

	payload := strings.NewReader("{\n  \"client_order_id\": \"0000-00000-000000\",\n  \"product_id\": \"BIT-28JUL23-CDE\",\n  \"size\": 3\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.coinbase.com/api/v3/brokerage/orders/close_position")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"client_order_id\": \"0000-00000-000000\",\n  \"product_id\": \"BIT-28JUL23-CDE\",\n  \"size\": 3\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.coinbase.com/api/v3/brokerage/orders/close_position")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"client_order_id\": \"0000-00000-000000\",\n  \"product_id\": \"BIT-28JUL23-CDE\",\n  \"size\": 3\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "success_response": {
    "order_id": "11111-00000-000000",
    "product_id": "BTC-USD",
    "side": "",
    "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",
      "currency_size": {
        "value": "1.23",
        "currency": "BTC"
      }
    },
    "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,
      "currency_size": {
        "value": "1.23",
        "currency": "BTC"
      }
    },
    "limit_limit_gtd": {
      "quote_size": "10.00",
      "base_size": "0.001",
      "limit_price": "10000.00",
      "end_time": "2021-05-31T09:59:59Z",
      "post_only": false,
      "currency_size": {
        "value": "1.23",
        "currency": "BTC"
      }
    },
    "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": "2021-05-31T07:59:59Z",
      "end_time": "2021-05-31T09:59:59Z",
      "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": "2021-05-31T09:59:59Z",
      "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": "2021-05-31T09:59:59Z"
    },
    "scaled_limit_gtc": {
      "orders": [
        {
          "quote_size": "10.00",
          "base_size": "0.001",
          "limit_price": "10000.00",
          "post_only": false,
          "currency_size": {
            "value": "1.23",
            "currency": "BTC"
          }
        }
      ],
      "quote_size": "<string>",
      "base_size": "<string>",
      "num_orders": 123,
      "min_price": "<string>",
      "max_price": "<string>",
      "price_distribution": "FLAT",
      "size_distribution": "UNKNOWN_DISTRIBUTION",
      "size_diff": "<string>",
      "size_ratio": "<string>"
    }
  }
}

{
  "error": "<string>",
  "code": 123,
  "message": "<string>",
  "details": [
    {}
  ]
}