What is Email Subject Line?
Quick Answer
The first line of text visible in the inbox before an email is opened — the primary driver of open rate.
The subject line is the single most important factor in email open rates. Best practices: keep it under 50 characters, create curiosity or urgency, personalize with the recipient's name or company, avoid spam trigger words (FREE, URGENT, !!!), and A/B test regularly. Emojis increase open rates by 56% in certain industries. MisarMail's AI subject line generator suggests optimized subject lines with predicted open rate uplift.
Related Terms
The percentage of delivered emails that were opened by recipients.
Preview Text (Preheader)The short text displayed after the subject line in the inbox, giving recipients additional context before opening.
A/B Testing (Split Testing)Sending different versions of an email to portions of your audience to determine which performs better.
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