It's important to know your message's spam rate before sending.
Email servers imply sophisticated technologies and spam filters to eliminate
spam attacks. Very often absolutely legal emails are marked as spam. Your
message may be regarded as spam, if it doesn't correspond to email servers'
This tool analyzes the email's source code and shows what types of
corrections should you bring about to lessen the spam rate, and correspondingly
to increase deliverability.
How to check emails:
Save your message from desktop or web email client to file.