Subject Line Tools — Test, Score & Generate Email Subject Lines
The writing half of the job: score what you've written, generate honest starting points when you're stuck, tune the emotional register with power words, and settle A/B arguments check by check. Every tool runs the same ten-check engine and shows its work — no black-box scores, nothing uploaded.
The tools
One engine, four tools
The tester, generator, power-words finder and A/B comparer all read your line with the same ten weighted checks — length band, word count, concrete numbers, curiosity frames, second person, power words, emoji, capitalization, exclamation stacking and a 175-word spam scan. Learn one tool's checklist and you've learned all four; disagree with one and you know exactly which check to argue with.
What 'good' looks like
A line that clears 80 does four things: fits 26–50 characters so mobile shows it whole, names something concrete (a number, a date, a noun from the reader's world), speaks to 'you', and opens one curiosity loop without shouting. 'Your Q4 plan: 2 spots left this month' — 37 characters, 8 words, a number, second person — scores 81. Nothing about it is clever; everything about it is visible.