Glossary
Preheader
Also called preview text, preheader text.
Last reviewed 18 September 2026
What is a preheader in an email?
A preheader is the line of text an inbox shows after the subject when there is room, taken from the top of the message body, and it is a separate opportunity rather than an extension of the subject line.
On a phone it is often the line that decides, and left unset it fills with whatever the email happens to begin with, which is frequently a logo alt text or the words “View this email in your browser”.
Writing it is close to free and almost nobody does it. In a course it is the natural home for the day number, on the mornings when the subject line needs its whole width for something more interesting.
See also
- Subject line
A subject line is the line an inbox shows beside your name, and the length that matters is not the total but the front of it: put what is interesting in the first 30 to 40 characters, which is roughly what an iPhone held upright will show.
- Call to action
A call to action is the single thing an email asks the reader to do, stated plainly and linked once, which in a course email is usually the step that day’s lesson was teaching rather than a request to buy anything.
- Email course
An email course is a finite sequence of lessons delivered one email at a time, in order, on a clock that starts when each reader joins, and it ends on a day both of you knew about in advance.
Read next
This term is covered properly in Subject lines for a 5-day email course: the Day N of M pattern, which is a longer piece on the subject.
Every other term is on the glossary index , the longer writing is in the guides, and what this site itself does is on the home page.
Thinking of writing one of these?
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Accounts are opened a few at a time rather than by signing up. Leave your address and you will be written to when the next ones open.
One message, when there is room. No course emails, no newsletter, and the address is not passed on. Ask and it is deleted; what is kept, and for how long, is in the privacy policy.