Secret (API Key):
When you are ready, click the button below

Sample payload:

The payload you should encode should look something similar to this:

  "purchase_options": [
      "article_id": "article_12345",
      "price": {
        "amount": 300,
        "currency": "EUR",
        "payment_model": "pay_later"
      "sales_model": "single_purchase",
      "title": "Buy all ComputerScience Articles",
      "currentArticle": "Buy only this one"
  "template": "459df825-ae0c-423d-a330-2154f982ea02"

Where the Purchase options are the purchase models defined as a json array and the template references the template UUID in the merchant dashboard, where you can define which elements will be matched

Also your secret is the API Key in your merchant account dashboard, under "Developers"

It should look like something like this: -----sample API key here-------