Subject Line Grader
Find out if your cold email subject lines are sending you to spam, or if they're optimized for opens. Real-time AI heuristic analysis.
Try adding a variable like {{firstName}}
0 chars
How we grade subject lines
Our algorithm reverse-engineers Google and Microsoft spam filters. We analyze character length, casing behavior, algorithmic spam trigger dictionaries, and personalization markers to predict inbox placement.
Start typing to see your real-time score
and deliverability breakdown.