10 prediction market apps compared: Kalshi, Polymarket and companion tools (checked Oct 2026)

By the All Things AI team Updated

Method: prices, account rules, offline support and data storage checked on each developer's own pages in October 2026, with sources linked under each pick. No affiliate links; nobody paid to be listed. How we checked

Short answer

To trade real-money event contracts in the US, Kalshi and Polymarket US are the CFTC-regulated options; both need an account and identity checks. Manifold uses play money, so it is the low-stakes way to practise. Our free browser tools sit beside those accounts for watchlists, expected-value math and a bet journal; none of them places trades.

Compare at a glance

10 prediction market apps compared: Kalshi, Polymarket and companion tools (checked Oct 2026): comparison table
App Best for Price Account needed Works offline Where data lives Platforms Status
Kalshi CFTC-regulated event contracts, US and international Free account; trading fees apply Required No Developer's cloud iPhone, Android, Web Available now
Polymarket US Polymarket's dollar-based US exchange Free account; trading fees not stated Required No Developer's cloud iPhone, Android Available now
Manifold Play-money forecasting with no real stakes Free (play money) Required No Developer's cloud Web, iPhone, Android Available now
Foresight Play-money prediction game Free (browser version) Not required No In your browser, on this device Web In App Review
Sidemarket Cross-platform watchlist with EV and Kelly math Free (browser version) Not required Yes In your browser, on this device Web Community proposal — try in browser
Linevigil Spotting sportsbook vs. Kalshi price gaps Free (browser version) Not required No In your browser, on this device Web Community proposal — try in browser
Wagerlog Journaling bets and tracking real ROI Free (browser version) Not required Yes In your browser, on this device Web Community proposal — try in browser
Brierboard Friendly forecasting tournaments Free (browser version) Not required No In your browser, on this device Web Community proposal — try in browser
Forecastly Training your calibration Free (browser version) Not required Yes In your browser, on this device Web Community proposal — try in browser
Newsedge Finding markets for a news story Free (browser version) Not required No In your browser, on this device Web Community proposal — try in browser

Scroll the table sideways on a phone. Third-party facts checked October 2026; prices can change, so confirm on the developer's site before you pay.

About “community proposal”: this is a community proposal. We build the iPhone/Android app once it reaches 100 upvotes. You can try the browser version free, with no sign-in; upvoting takes a Google sign-in.

  1. Kalshi

    Available now Other developer

    CFTC-regulated event contracts, US and international

    Kalshi is a CFTC-regulated Designated Contract Market; users must be 18+ and may be asked for ID, US state restrictions are not listed on its help pages, and some international jurisdictions are restricted under its Member Agreement.

    Price
    Free to open an account; per-trade fees per Kalshi's fee schedule
    Account
    Required
    Offline
    No
    Data
    Developer's cloud
    Visit Kalshi ↗

    Source: help.kalshi.com/en/articles/13823778-signing-up-as-an-individual · help.kalshi.com/en/articles/14026044-can-i-trade-… · checked Oct 2026

  2. Polymarket US

    Available now Other developer

    Polymarket's dollar-based US exchange

    Polymarket US (QCX LLC) is a CFTC-designated contract market, separate from the crypto-based international polymarket.com; it requires 18+ and identity checks including SSN, and its App Store listing says trading is currently unavailable in Nevada.

    Price
    Free to download and open an account; trading fees not stated
    Account
    Required
    Offline
    No
    Data
    Developer's cloud
    Visit Polymarket US ↗

    Source: apps.apple.com/us/app/polymarket/id6648798962 · docs.polymarket.us/learn/get-started/signup · checked Oct 2026

  3. Manifold

    Available now Other developer

    Play-money forecasting with no real stakes

    Mana is play money that cannot be converted to cash, so Manifold is not a CFTC-regulated exchange; new users start with Ṁ1,000, and its cash sweepstakes product ended in March 2025.

    Price
    Free; optional in-app purchases of play money (mana)
    Account
    Required
    Offline
    No
    Data
    Developer's cloud
    Visit Manifold ↗

    Source: manifold.markets/about · news.manifold.markets/p/focusing-on-mana-bringing… · checked Oct 2026

  4. Foresight

    In App Review By All Things AI

    Forecast real events. Sharpen your foresight.

    Price
    Free (browser version)
    Account
    Not required
    Offline
    No
    Data
    In your browser, on this device
    Try Foresight free in your browser App page

  5. Sidemarket

    Community proposal — try in browser By All Things AI

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

    Price
    Free (browser version)
    Account
    Not required
    Offline
    Yes
    Data
    In your browser, on this device
    Try Sidemarket free in your browser App page and upvotes

  6. Linevigil

    Community proposal — try in browser By All Things AI

    Where the books and Kalshi disagree. Watch the gap.

    Price
    Free (browser version)
    Account
    Not required
    Offline
    No
    Data
    In your browser, on this device
    Try Linevigil free in your browser App page and upvotes

  7. Wagerlog

    Community proposal — try in browser By All Things AI

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

    Price
    Free (browser version)
    Account
    Not required
    Offline
    Yes
    Data
    In your browser, on this device
    Try Wagerlog free in your browser App page and upvotes

  8. Brierboard

    Community proposal — try in browser By All Things AI

    Forecasting tournaments with your friends.

    Price
    Free (browser version)
    Account
    Not required
    Offline
    No
    Data
    In your browser, on this device
    Try Brierboard free in your browser App page and upvotes

  9. Forecastly

    Community proposal — try in browser By All Things AI

    A personal calibration journal. Get better at being right.

    Price
    Free (browser version)
    Account
    Not required
    Offline
    Yes
    Data
    In your browser, on this device
    Try Forecastly free in your browser App page and upvotes

  10. Newsedge

    Community proposal — try in browser By All Things AI

    Read a story. See the markets that move.

    Price
    Free (browser version)
    Account
    Not required
    Offline
    No
    Data
    In your browser, on this device
    Try Newsedge free in your browser App page and upvotes

The longer answer

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.

How we checked

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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