Introducing Subject Line Checker
Test your subject lines and preview text in 15+ email clients
Find out more
 
See how your subject lines will look to your subscribers before you press send with Subject Line Checker, now available in Checklist and Builder. We like it so much, we used it to test this very email!

With Subject Line Checker, you get:
Real-time previews
Your previews will automatically update as you write and edit your subject line and preview text, alerting you if either are too long, too short, or using emojis that are not supported.
Mobile + desktop views
Preview in over 15 of the most popular email clients, including Outlook, Gmail, and iOS.
Issues at a glance
Quickly get an overview of all potential issues with visual alerts for each client.
Emoji support
Itching to use a monkey covering its eyes in your next email? Subject Line Checker shows you which clients will support it.
Subject Line Checker is available with a paid Litmus account. Try out Subject Line Checker, along with Instant Previews in 50+ clients and devices, comprehensive spam filter testing, and robust Email Analytics as part of a 7-day trial.
Find your package →