Paste your subject line — check its length and scan for common spam-trigger words.
Nothing you type here leaves your browser. We check the character length against what typically displays fully in an inbox preview, and scan for words that commonly trip email spam filters. Run every subject line through this before it goes out — pairing it with our editorial calendar planner makes that a habit, not a one-off.
Words historically overused by scam and marketing spam ('free', 'guaranteed', 'act now') train spam filters to flag them — using one occasionally won't hurt you, but stacking several in one subject line raises the risk.
Around 30–50 characters tends to display fully on both desktop and mobile inbox previews — much longer and it gets cut off before the reader sees the point.