curl --request POST \
  --url https://api-sandbox.circle.com/v1/paymentIntents/{id}/refund \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "idempotencyKey": "ba943ff1-ca16-49b2-ba55-1057e70ca5c7",
  "destination": {
    "address": "0x8381470ED67C3802402dbbFa0058E8871F017A6F",
    "addressTag": "123456789",
    "addressBookId": "e7f468c7-6a99-5639-b3ed-8c7d477abb47"
  },
  "amount": {},
  "toAmount": {
    "amount": "3.14"
  },
  "paymentId": "2e7b6557-1967-4348-ad81-daf3cee4c175"
}
'

import requests

url = "https://api-sandbox.circle.com/v1/paymentIntents/{id}/refund"

payload = {
    "idempotencyKey": "ba943ff1-ca16-49b2-ba55-1057e70ca5c7",
    "destination": {
        "address": "0x8381470ED67C3802402dbbFa0058E8871F017A6F",
        "addressTag": "123456789",
        "addressBookId": "e7f468c7-6a99-5639-b3ed-8c7d477abb47"
    },
    "amount": {},
    "toAmount": { "amount": "3.14" },
    "paymentId": "2e7b6557-1967-4348-ad81-daf3cee4c175"
}
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({
    idempotencyKey: 'ba943ff1-ca16-49b2-ba55-1057e70ca5c7',
    destination: {
      address: '0x8381470ED67C3802402dbbFa0058E8871F017A6F',
      addressTag: '123456789',
      addressBookId: 'e7f468c7-6a99-5639-b3ed-8c7d477abb47'
    },
    amount: {},
    toAmount: {amount: '3.14'},
    paymentId: '2e7b6557-1967-4348-ad81-daf3cee4c175'
  })
};

fetch('https://api-sandbox.circle.com/v1/paymentIntents/{id}/refund', 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-sandbox.circle.com/v1/paymentIntents/{id}/refund",
  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([
    'idempotencyKey' => 'ba943ff1-ca16-49b2-ba55-1057e70ca5c7',
    'destination' => [
        'address' => '0x8381470ED67C3802402dbbFa0058E8871F017A6F',
        'addressTag' => '123456789',
        'addressBookId' => 'e7f468c7-6a99-5639-b3ed-8c7d477abb47'
    ],
    'amount' => [
        
    ],
    'toAmount' => [
        'amount' => '3.14'
    ],
    'paymentId' => '2e7b6557-1967-4348-ad81-daf3cee4c175'
  ]),
  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-sandbox.circle.com/v1/paymentIntents/{id}/refund"

	payload := strings.NewReader("{\n  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"destination\": {\n    \"address\": \"0x8381470ED67C3802402dbbFa0058E8871F017A6F\",\n    \"addressTag\": \"123456789\",\n    \"addressBookId\": \"e7f468c7-6a99-5639-b3ed-8c7d477abb47\"\n  },\n  \"amount\": {},\n  \"toAmount\": {\n    \"amount\": \"3.14\"\n  },\n  \"paymentId\": \"2e7b6557-1967-4348-ad81-daf3cee4c175\"\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-sandbox.circle.com/v1/paymentIntents/{id}/refund")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"destination\": {\n    \"address\": \"0x8381470ED67C3802402dbbFa0058E8871F017A6F\",\n    \"addressTag\": \"123456789\",\n    \"addressBookId\": \"e7f468c7-6a99-5639-b3ed-8c7d477abb47\"\n  },\n  \"amount\": {},\n  \"toAmount\": {\n    \"amount\": \"3.14\"\n  },\n  \"paymentId\": \"2e7b6557-1967-4348-ad81-daf3cee4c175\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api-sandbox.circle.com/v1/paymentIntents/{id}/refund")

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  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"destination\": {\n    \"address\": \"0x8381470ED67C3802402dbbFa0058E8871F017A6F\",\n    \"addressTag\": \"123456789\",\n    \"addressBookId\": \"e7f468c7-6a99-5639-b3ed-8c7d477abb47\"\n  },\n  \"amount\": {},\n  \"toAmount\": {\n    \"amount\": \"3.14\"\n  },\n  \"paymentId\": \"2e7b6557-1967-4348-ad81-daf3cee4c175\"\n}"

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

{
  "data": {
    "id": "3389f4ba-aafd-4eef-aaa2-3292df8f62e6",
    "type": "refund",
    "status": "pending",
    "amount": {
      "currency": "USD"
    },
    "merchantId": "5ffea093-d210-44b4-a7ca-ad33b9498188",
    "merchantWalletId": "1000999922",
    "paymentIntentId": "77c91fe9-e603-4e7b-9672-1ef8ac502cf6",
    "settlementAmount": {
      "amount": "1.00",
      "currency": "ETH"
    },
    "fromAddresses": {
      "chain": "ETH",
      "addresses": [
        "0x0d4344cFF68F72A5B9Abded37CA5862941a62050"
      ]
    },
    "depositAddress": {
      "chain": "ETH",
      "address": "0x97de855690955e0da79ce5c1b6804847e7070c7f"
    },
    "paymentId": "2e7b6557-1967-4348-ad81-daf3cee4c175",
    "createDate": "2022-07-21T20:16:35.092852Z",
    "updateDate": "2022-07-21T20:19:24.719313Z"
  }
}

{
  "code": 400,
  "message": "Bad request."
}

{
  "code": 401,
  "message": "Malformed authorization."
}

{
  "code": 404,
  "message": "Not found."
}