Best prediction market apps for Kalshi & Polymarket, 2026

Kalshi and Polymarket give you the markets, but neither gives you the discipline: a watchlist, the EV math, and an honest record of whether your edge is real. These five apps are the companion tools that sit beside your trading account rather than inside it. Sidemarket builds a cross-platform watchlist with open EV and Kelly math plus a base-rate library; Linevigil tracks the gap where sportsbook lines and Kalshi odds disagree; Wagerlog journals every wager across platforms and computes CLV and true ROI; Brierboard runs friendly Brier-scored forecasting tournaments with friends; and Forecastly trains your personal calibration curve so you learn when your gut is actually right. None place trades or touch your money, so your positions and history stay on your own device.

TestFlight beta Finance

#1 Sidemarket

A calm watchlist for prediction markets. Bring your own EV.

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TestFlight beta Sports

#2 Linevigil

Where the books and Kalshi disagree. Watch the gap.

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TestFlight beta Finance

#3 Wagerlog

Every bet, one journal. CLV and EV, no spreadsheet.

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TestFlight beta Social Networking

#4 Brierboard

Forecasting tournaments with your friends.

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TestFlight beta Productivity

#5 Forecastly

A personal calibration journal. Get better at being right.

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FAQ

Do these apps place trades on Kalshi or Polymarket? ▾

No. None of them connect to your trading account, place orders, or handle real money. Sidemarket and Linevigil are watchlists and decision tools, Wagerlog is a journal, and Brierboard and Forecastly are forecasting and calibration tools. You still trade on Kalshi or Polymarket directly; these apps help you decide and keep score.

Is my trading data kept private? ▾

Yes. Because these apps don't link to your brokerage account or broadcast your positions, your watchlists, trade journal, and forecasting history stay on your own device. Sidemarket explicitly doesn't connect to your account or broadcast your positions, and Wagerlog is a single private journal with no bookmaker integration.

What's the difference between Sidemarket, Wagerlog, and Forecastly? ▾

Sidemarket is a forward-looking watchlist and EV/Kelly calculator for markets you're considering on Kalshi and Polymarket. Wagerlog is a backward-looking journal that logs every wager across platforms and computes EV, closing line value, and ROI by book and sport. Forecastly isn't about money at all; it's a calibration journal that scores your predictions with Brier scores and plots where your confidence drifts from reality.

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