Email Subject Line & Preheader Tester
Check character counts, wording signals and an inbox preview without sending an email.
Free · No sign-up · Runs in your browser
Your result
Choose your settings, then run the tool to see the result.
How to use this tool
- Check character counts, wording signals and an inbox preview without sending an email.
- Choose the input and settings below. Example values can be replaced.
- Run the tool and check the preview and any notices.
- Download the result. Your original input files stay unchanged.
Scope & privacy
Heuristic writing checks only. Inbox appearance varies; this does not predict open rates or guarantee spam-filter placement.
No. Processing happens in your browser. No files, email content or calculation inputs are sent to our server.
What should I check before using the result?
Scope & privacy
Heuristic writing checks only. Inbox appearance varies; this does not predict open rates or guarantee spam-filter placement.
Are my inputs uploaded?
No. Processing happens in your browser. No files, email content or calculation inputs are sent to our server.
Put the result to work
Continue in your connected workspace to save, manage and use the result.