curl --request POST \
  --url https://my.server.express/api/v1/dedicated/{id}/addons \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "addonProductId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "quantity": 1
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({addonProductId: '3c90c3cc-0d44-4b50-8888-8dd25736052a', quantity: 1})
};

fetch('https://my.server.express/api/v1/dedicated/{id}/addons', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://my.server.express/api/v1/dedicated/{id}/addons"

payload = {
    "addonProductId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "quantity": 1
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

{
  "success": true,
  "data": {
    "addonId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "invoiceId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "invoiceNumber": "<string>",
    "total": 123,
    "currency": "GBP"
  }
}

{
  "success": false,
  "error": "<string>"
}

{
  "success": false,
  "error": "<string>"
}

{
  "success": false,
  "error": "<string>"
}

{
  "success": false,
  "error": "<string>"
}

{
  "success": false,
  "error": "<string>"
}