Know which headline wins before you spend traffic on it.
AI writing critique tool for serious authors
Stage
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Founded
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Pricing model
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Pricing
Free: $0/month with 5 rankings and 60 Claude-written options monthly. Creator: $19/month with 100 rankings and 2,500 options. Pro: $49/month with 600 rankings and 6,000 options. Agency: $149/month with 3,000 rankings and 20,000 options.
Core Plan: $19/month (200,000 words of editing per month, limited rewriting ability). Pro Plan: $29/month (300,000 words of editing per month, able to rewrite entire chapters and books). A one-time free word sample is available for new accounts.
Key features
Head-to-head comparison of up to 200 variants
Bradley-Terry model ranking with calibrated odds
Honest uncertainty verdicts: Clear, Lean, Too close to call
Brand profiles to calibrate accuracy on your audience
Works for YouTube titles, subject lines, ad headlines, and article headlines
Accuracy measured on 9,841 held-out A/B tests
Sentence-level literary feedback
Paragraph-level literary feedback
Passage-level literary feedback in context
Chapter-level literary feedback in context
Book-level literary feedback in entire context
One-click text rewriting with AI
Entire chapter rewriting on Pro Plan
Entire book rewriting on Pro Plan
300,000-word context window on Pro Plan
Progressive learning through interactive Q&A
What makes it different
82% accuracy on clear calls, trained on thousands of real A/B tests never seen during tuning
Honest about uncertainty instead of always crowning a winner
56 times cheaper than Claude Sonnet while maintaining comparable accuracy
Custom calibration to your audience's behavior via brand profiles
Compare versions in both orders to cancel out model bias
Human book editors charge thousands but AI Book Editor starts at $19 per month
Gives almost immediate feedback while human editors take weeks
300,000-word context window three times more than average novel
All output belongs 100% to the user for commercial use