EMAIL GUIDE
Email Subject Line Checklist
Use a few simple checks before sending an email campaign.
Make the main idea clear
The recipient should have a reasonable idea of what the message contains without needing to decode vague wording.
Review length and punctuation
Very long subjects can be truncated on some screens. Multiple exclamation marks, repeated punctuation, or excessive capitalization can also make a subject feel less natural.
Match the audience and email
Avoid promising something the email does not deliver. Relevance and accurate expectations matter more than trying to trigger a particular scoring formula.
Do not confuse a checklist with deliverability prediction
No subject-line heuristic can guarantee inbox placement. Sender reputation, authentication, message content, engagement, recipient systems, and provider policies all matter.