curl --request POST \
  --url https://api.shoppex.io/dev/v1/subscriptions/{id}/change-plan/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "new_plan_id": "<string>"
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({new_plan_id: '<string>'})
};

fetch('https://api.shoppex.io/dev/v1/subscriptions/{id}/change-plan/preview', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://api.shoppex.io/dev/v1/subscriptions/{id}/change-plan/preview"

payload = { "new_plan_id": "<string>" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.shoppex.io/dev/v1/subscriptions/{id}/change-plan/preview",
  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([
    'new_plan_id' => '<string>'
  ]),
  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.shoppex.io/dev/v1/subscriptions/{id}/change-plan/preview"

	payload := strings.NewReader("{\n  \"new_plan_id\": \"<string>\"\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))

}

{
  "data": {
    "current_plan_id": "<string>",
    "new_plan_id": "<string>",
    "quote": {
      "quote_id": "<string>",
      "effective": "now",
      "effective_at": "<string>",
      "due_now": "<string>",
      "small_amount_waived": true,
      "currency": "<string>",
      "lines": [
        {
          "kind": "new_plan_days",
          "plan_name": "<string>",
          "days": 123,
          "from": "<string>",
          "to": "<string>",
          "amount": "<string>"
        }
      ],
      "next_amount": "<string>",
      "next_date": "<string>",
      "days_left": 123,
      "days_total": 123,
      "collection": "card",
      "expires_at": "<string>",
      "replaces": {
        "change_id": "<string>",
        "plan_name": "<string>",
        "effective_at": "<string>"
      }
    }
  }
}

{
  "status": 123,
  "data": null,
  "error": "<string>",
  "message": "<string>",
  "log": null,
  "env": "<string>"
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "doc_url": "<string>",
    "details": [
      {
        "field": "<string>",
        "message": "<string>"
      }
    ],
    "subcode": "<string>"
  }
}