curl --request POST \
  --url https://uat-api.clinkbill.com/api/subscription/{id}/update/preview \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --header 'X-Timestamp: <x-timestamp>' \
  --data '
{
  "priceId": "price_xxxx",
  "promotionCode": "SUMMER25"
}
'

HttpResponse<String> response = Unirest.post("https://uat-api.clinkbill.com/api/subscription/{id}/update/preview")
  .header("X-Timestamp", "<x-timestamp>")
  .header("X-API-KEY", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"priceId\": \"price_xxxx\",\n  \"promotionCode\": \"SUMMER25\"\n}")
  .asString();

import requests

url = "https://uat-api.clinkbill.com/api/subscription/{id}/update/preview"

payload = {
    "priceId": "price_xxxx",
    "promotionCode": "SUMMER25"
}
headers = {
    "X-Timestamp": "<x-timestamp>",
    "X-API-KEY": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-Timestamp': '<x-timestamp>',
    'X-API-KEY': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({priceId: 'price_xxxx', promotionCode: 'SUMMER25'})
};

fetch('https://uat-api.clinkbill.com/api/subscription/{id}/update/preview', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "code": 200,
  "msg": "success",
  "data": {
    "subscriptionId": "<string>",
    "immediate": true,
    "recurringPrice": {
      "periodStart": 123,
      "periodEnd": 123,
      "priceId": "<string>",
      "priceSnapshotId": "<string>",
      "productId": "<string>",
      "productName": "<string>",
      "totalAmount": 123,
      "unitAmount": 123,
      "currencySymbol": "<string>",
      "quantity": 123,
      "recurring": "<string>"
    },
    "lines": {
      "proratedCredit": {
        "productName": "<string>",
        "totalAmount": 123,
        "currencySymbol": "<string>",
        "quantity": 123
      },
      "proratedCharge": {
        "productName": "<string>",
        "totalAmount": 123,
        "currencySymbol": "<string>",
        "quantity": 123
      },
      "periodStart": 123,
      "periodEnd": 123,
      "subtotalAmount": 123,
      "taxAmount": 123,
      "taxRate": 123,
      "taxName": "<string>",
      "totalAmount": 123,
      "currencySymbol": "<string>"
    },
    "discountObject": {
      "couponId": "<string>",
      "couponName": "<string>",
      "couponTerms": "<string>",
      "promotionCode": "<string>",
      "discountAmount": 123,
      "durationType": "<string>",
      "durationMonths": 123,
      "couponUsedTimes": 123
    }
  }
}

"<string>"