curl --request POST \
  --url https://app.herondata.io/api/end_user_files/process_standalone \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
  "expected_file_class": "<string>",
  "file_content_base64": "<string>",
  "filename": "<string>",
  "reference_id": "<string>"
}'

{
  "reference_id": "<string>"
}