curl --location --request GET '/campaigns/statistics/by-day?from&to' \
--header 'x-workspace;' \
--header 'X-API-Key: <api-key>'[
{
"date": "2019-08-24",
"sent": 0,
"delivered": 0,
"opened": 0,
"clicked": 0,
"replied": 0
}
]