curl --request POST \
  --url https://api.withflex.com/v1/checkout/sessions/{id}/refund \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "checkout_session": {
    "line_items": []
  }
}
'

import requests

url = "https://api.withflex.com/v1/checkout/sessions/{id}/refund"

payload = { "checkout_session": { "line_items": [] } }
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({checkout_session: {line_items: []}})
};

fetch('https://api.withflex.com/v1/checkout/sessions/{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.withflex.com/v1/checkout/sessions/{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([
    'checkout_session' => [
        'line_items' => [
                
        ]
    ]
  ]),
  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.withflex.com/v1/checkout/sessions/{id}/refund"

	payload := strings.NewReader("{\n  \"checkout_session\": {\n    \"line_items\": []\n  }\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.withflex.com/v1/checkout/sessions/{id}/refund")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"checkout_session\": {\n    \"line_items\": []\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.withflex.com/v1/checkout/sessions/{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  \"checkout_session\": {\n    \"line_items\": []\n  }\n}"

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

{
  "checkout_session": {
    "allow_promotion_codes": false,
    "amount_total": 2500,
    "amount_subtotal": 2500,
    "amount_received": 2500,
    "amount_refunded": 2500,
    "amount_disputed": 2500,
    "cancel_url": "https://example.com",
    "captures": [],
    "disputes": [],
    "capture_method": "automatic",
    "checkout_session_id": "fcs_01J9XR8M3K7VZ8N2YB4WJ6T0RA",
    "client_reference_id": "example_value",
    "created_at": 2500,
    "defaults": {},
    "expires_at": 2500,
    "invoice": "fin_01J9XR8M3K7VZ8N2YB4WJ6T0RA",
    "hsa_fsa_eligible": false,
    "letter_of_medical_necessity_required": false,
    "metadata": {
      "order_id": "8842",
      "channel": "shopify"
    },
    "mode": "payment",
    "origin": "shopify",
    "redirect_url": "https://example.com",
    "refunds": [],
    "setup_intent": "fseti_01J9XR8M3K7VZ8N2YB4WJ6T0RA",
    "shipping_options": {},
    "shipping_address_collection": false,
    "shipping_details": {},
    "status": "open",
    "success_url": "https://example.com",
    "fees": [
      {}
    ],
    "custom_text": {},
    "subscription_data": {},
    "tax_rate": {},
    "tax_calculation_mode": "exclusive",
    "test_mode": false,
    "total_details": {
      "amount_discount": 2500,
      "amount_tax": 2500,
      "amount_shipping": 2500,
      "amount_iias": 2500,
      "amount_vision": 2500,
      "amount_prescription": 2500,
      "amount_service": 2500,
      "amount_fee": 2500
    },
    "visit_type": "cbtSleep",
    "setup_future_use": "on_session",
    "payment_method_options": {},
    "platform_fees": {}
  }
}

{
  "code": "string",
  "detail": "string"
}

{
  "code": "string",
  "detail": "string"
}

{
  "code": "string",
  "detail": "string"
}

{
  "code": "string",
  "detail": "string"
}

{
  "detail": [
    {
      "loc": [
        "string"
      ],
      "msg": "string",
      "type": "string"
    }
  ]
}

{
  "code": "string",
  "detail": "string"
}