To use an API key for authentication in an HTTPS API call, you must include the API key in the message header of the content modifier step. The message header contains information related to the message, such as addressing, routing, or metadata. You can use the content modifier step to create or modify message headers using expressions or constants. The API key is typically passed as a value of a specific header field, such as Authorization or X-API-Key, depending on the API provider’s requirements. You can use the Camel Simple Expression Language to access or construct the API key value from variables, properties, or system information. References: Content Modifier | SAP Help Portal, Using Camel Simple Expression Language | SAP Help Portal