curl --location --request POST '/api/download/submit?utm_source&utm_medium&utm_campaign' \
--header 'Content-Type: application/json' \
--data-raw '{
"bookSlug": "the-great-controversy",
"languageCode": "en",
"fileType": "pdf",
"contact": {
"firstName": "John",
"email": "john@example.com",
"country": "US"
}
}'{
"downloadUrl": "/api/download/eyJhbGciOiJIUzI1NiJ9..."
}