curl --request POST \
  --url https://app.herondata.io/api/iso_applications/base64 \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
  "file_base64": "base64_encoded_string",
  "filename": "iso_app.pdf",
  "reference_id": "your-file-id"
}'

{
  "heron_id": "<string>",
  "status": "processing"
}