Use the x-api-key header to include the API key generated previously for authentication purposes. The API key serves as a secret token that identifies the client or application making the request and is used to determine whether the client has the necessary permissions to access the requested resource.

Use the x-aggregator-id header to identify the aggregator for a particular request. An aggregator is the entity that is involved in the processing of transactions or data. By including the id in the header, the server can identify which aggregator the request owns and handle the request accordingly.