You're being asked to put your trading history into a tool you just found. That's a reasonable thing to be careful about. Here's exactly how it works, in plain language.
Your CSV is parsed in your browser
When you drop a Kalshi CSV on the home page, it's read and analyzed locally in your browser. The raw file is not uploaded to a server to generate your dashboard. You can watch it work with your network tab open.
What's stored, and only if you sign in
If you create an account to save your history or join the leaderboard, we store the computed results you opt to save (totals, your Sharp Score, your chosen handle), not your raw trade-by-trade file. If you never sign in, nothing about your trades is retained after you close the tab.
We never sell your data
Your data is used to show you your analytics and, only if you opt in, to compute anonymized aggregate stats (the kind on our State of Kalshi page, where no individual is identifiable). It is never sold or shared with advertisers. There are no ads.
It's yours to delete
Delete your saved data at any time from your dashboard (the Community tab has a Your Data panel), or email us and we'll handle it. Leaving the leaderboard removes your handle and stats from it immediately.
Educational, not tax or financial advice
ContractTax models your numbers under each possible tax treatment so you can have an informed conversation with a professional. The treatment of prediction-market gains is genuinely unsettled. We show you the options honestly; we don't tell you which to claim, and we're not your accountant.
Independent, and not affiliated with Kalshi
ContractTax is an independent tool built by a Kalshi trader who got tired of doing this by hand. It is not affiliated with, endorsed by, or operated by Kalshi. "Kalshi" is referenced only to describe what the tool works with.
Still have a question?
Email hello@contracttax.com and a real person (the one who built this) will answer. The fastest way to trust the tool is to try it on the live demo first, with sample data, before you upload a thing.