Email Subject Line Generator

In short A subject line has to survive truncation, and that is the constraint everything else follows from: most mobile clients show only 35 to 45 characters. The information has to be in that first half, which means the specific noun goes at the front and the qualifier at the back — "Invoice 4417 overdue" rather than "A quick note about an invoice that is now overdue". The second thing people leave on the table is preview text. The first line of the email body shows next to the subject in almost every client, so it is part of the hook whether you treat it as one or not; starting an email with "Hi Sarah," spends that space on nothing. The four angles that reliably work are curiosity, benefit, urgency and personalisation, and they work in different proportions for different lists — the only way to know is to test one variable at a time. Two things to avoid: urgency you cannot back up, which trains people to ignore you, and anything that reads as a subject line rather than as a message from a person.