To authenticate requests, Nuvei REST API 2.0 uses the merchant’s API key, which the Nuvei Integration Team provides. The merchant includes its API key in the request header:

x-api-key: <your API key>

Example POST /payments Request

POST  /payment-api/payments HTTPS/1.1 
Host: api.nuvei.com
Content-Type: application/json 
x-api-key: <your API key>

{
  "processingEntityId": "dbdaacd8-e2b8-4e80-81e7-736a3e241fd0",
  "transactionType": "Sale",
  "amount": 60,
  "currency": "EUR",
...
}