lol

#!/bin/bash
file="emails.txt"
api_url="..."
authorization="<user>:<api_key>"

mail_count=$(cat $file | wc -l)
#convert to integer by adding 0:p
mail_count=$(($mail_count+0))
echo $mail_count
json_arr="["
i=1
quote="\""

while read line
do
    json_arr+=$quote
    json_arr+=$line
    json_arr+=$quote

    if [ $i -ne $mail_count ]
    then
        json_arr+=","
    fi

    i=$((i + 1))
done <$file

json_arr+="]"

json_data="{\"mails\":$json_arr}"

curl -X POST -H 'Content-Type: application/json' -d $json_data  $api_url --user $authorization