FillBook is a specialized trade journal designed for Kalshi traders, offering automated import of trading fills and insightful analysis to understand profitability. It addresses the limitations of generic trading journals by understanding prediction market specifics like contract settlements and market categories.

• Auto-import from Kalshi: Seamlessly import your trading data by pasting a read-only Kalshi API key. The platform normalizes and groups your fills and settlements into positions, with CSV upload also available.
• P&L you can trust: Calculate realized Profit & Loss with fees included, accounting for weighted-average cost on partial closes and correct settlement to $1 or $0.
• Edge by category: Analyze win rates and average win/loss across different market categories (politics, sports, weather, econ, crypto), venues, and days of the week to identify your true edge.
• A real journal: Add notes and tags to each position, documenting your thesis, setup, mistakes, and emotions to learn from your trades and avoid repeating errors.
• Edge decay: Understand how your P&L changes based on holding duration, providing insights into whether your edge diminishes over time.
• Data privacy: FillBook never places trades or sells your data. All data can be deleted upon request, ensuring read-only access from day one.

FillBook offers a Free forever plan with unlimited trade storage and 60-day analytics, and a Pro plan for $15/month that includes full-history analytics and all future Pro features. The service is designed to help prediction market traders move beyond spreadsheets and gain a clear understanding of their trading performance.