Marketing GlossarySubject Line

Subject Line

June 2025

What is a subject line?

A subject line is a piece of introductory text which acts as a preview for the message contents.

The decision of whether or not to open an email is often based on the subject line alone. Therefore, marketers must craft engaging subject lines which intrigue users so that their emails get clicked on.

The best subject lines are those which are relevant to the content found inside the email, since getting users to open an email is only half the battle.

However, when done well, subject lines can deliver incredible results for marketers by encourage more clicks, engagements and conversions.

Example

The EcoSend AI Subject Line Generator helps you to craft amazing subject lines at the click of a button.

So whether you're stuck for ideas, or simply want to try something new, it's free to try.

You can then use these subject lines (including your own of course) within EcoSend.

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