FillBook
Sign inStart free

The Kalshi trade journal

See what your Kalshi trading actually makes you, after fees

Connect read-only and get your real P&L with fees folded in, win rate by market type, and where your edge actually is. Then check it against Kalshi's own numbers with one click, because a journal you cannot verify is worth nothing.

Start freeSee a live demo, no signup

Free forever plan · No card required · Read-only API key or CSV, no key needed

fillbook.io/demo
FillBook dashboard: realized P&L with fees, win rate by category, equity curve, and edge by day of week
This is live sample data — click to explore it, no signup →

Generic trading journals weren't built for this

Stock and options journals can't import a Kalshi API key, don't understand contracts that settle to $1 or $0, and have no idea what "politics," "econ" or "weather" edge means. So Kalshi traders end up in spreadsheets — or flying blind.

Verified, not promised

Check our math against Kalshi's

Kalshi publishes its own realized P&L for every market you traded. FillBook recomputes yours from raw fills, then compares the two market by market and shows anything that disagrees by more than a cent of rounding.

It is one button on your Analytics page. Getting there took fixing five things most Kalshi P&L math gets wrong, which we wrote up in full: why your Kalshi P&L is wrong.

Check against Kalshi

All 180 settled markets agree with Kalshi, within $0.06 in total rounding.

KXNFLGAME-26SEP20GBNYJ-GB +$20.00 / +$20.00

KXPGATOUR-USO26-KBRA -$1.99 / -$1.99

KXNCAABASEBALL-26-OKLA +$121.67 / +$121.67

Real output from a 596-fill account, Kalshi's figure first.

“This is a cool tool to have. Nice to be able to see the breakdown.”
Brad Q, Kalshi trader, 596 fills imported

Everything a prediction-market trader needs to review their book

Auto-import from Kalshi

Paste a read-only Kalshi API key. We pull your fills and settlements, normalize them, and group them into positions. CSV upload too.

P&L you can verify

Realized P&L with fees folded in, weighted-average cost on partial closes, fractional contracts and sub-cent prices kept exact. One button reconciles every settled market against Kalshi's own realized figures and shows anything that disagrees.

Edge by market type

Win rate and average win/loss by category and by Kalshi's own market families, so college football sits apart from the NFL and PGA apart from both. Also by venue and day of week.

A real journal

Notes and tags on every position: your thesis, your setup, your mistakes, your emotions. Review your losses and stop repeating them.

Open positions, marked

Open trades are valued at the current bid on your side, so you see realized, unrealized and a total — not just what you have already banked. Plus P&L by holding duration, an early read on edge decay.

Your data, yours

We never place trades. We never sell your data. Delete everything on request. Read-only, from day one.

Simple pricing

Start free with Kalshi and Polymarket. Upgrade for all-time analytics.

Free

$0 forever

  • ✓Kalshi and Polymarket import, daily auto-sync
  • ✓Analytics for the last 60 days
  • ✓Check every settled market against Kalshi
  • ✓Journal notes and tags, weekly summary email
Start free

Pro

$15 /month

  • ✓Everything in Free
  • ✓All-time analytics, sport and market-type breakdown included
  • ✓Account tie-out: deposits against what your trades made
  • ✓Export every position as a CSV
Go Pro

Frequently asked

Is my Kalshi API key safe?

We ask for a read-scoped key and encrypt the private key at rest. We only read fills, positions and settlements — we can't place or cancel orders.

How is P&L calculated?

Per position (one market, one side), using weighted-average cost for partial closes, with the exchange's own per-fill fee subtracted and settlement to $1 or $0 per contract. Fractional contracts and sub-cent prices are kept exact, and Kalshi's full fill history is read, including the older fills served from a separate endpoint.

How do I know the numbers are right?

Check them. Kalshi publishes its own realized P&L per market, and the Analytics page has a button that compares every settled market in your account against it and lists anything that differs by more than a cent of rounding. On the accounts we have run it against, all of them match.

Which venues do you support?

Kalshi (read-only API key) and Polymarket (paste your wallet address, no keys). Both import into one journal with one P&L. Other venues are driven by demand, so tell us what you trade.

Can I cancel anytime?

Yes. Pro is month-to-month; cancel whenever and you keep access through the period you paid for.

Free Kalshi resources

Stop guessing where your edge is

Import your fills in minutes. See the truth about your trading.

Start free