curl --request POST \
  --url https://merchant-demo.zahlo.eu/api/v1/customer-portal/sessions \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "customerId": "cus_demo_1001",
  "returnUrl": "https://app.example.com/settings/billing"
}
'

import requests

url = "https://merchant-demo.zahlo.eu/api/v1/customer-portal/sessions"

payload = {
    "customerId": "cus_demo_1001",
    "returnUrl": "https://app.example.com/settings/billing"
}
headers = {
    "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-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    customerId: 'cus_demo_1001',
    returnUrl: 'https://app.example.com/settings/billing'
  })
};

fetch('https://merchant-demo.zahlo.eu/api/v1/customer-portal/sessions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "id": "cps_demo_1001",
  "url": "https://portal.zahlo.eu/cps_demo_1001",
  "expiresAt": "2026-09-02T12:30:00Z"
}

{
  "error": "invalid_request",
  "message": "amountMinor must be positive",
  "requestId": "req_demo_1001"
}

{
  "error": "invalid_request",
  "message": "amountMinor must be positive",
  "requestId": "req_demo_1001"
}

{
  "error": "invalid_request",
  "message": "amountMinor must be positive",
  "requestId": "req_demo_1001"
}

{
  "error": "invalid_request",
  "message": "amountMinor must be positive",
  "requestId": "req_demo_1001"
}