🎁 Get the FREE AI Skills Starter Guide β€” Subscribe β†’
BytesAgainBytesAgain
BytesAgain β€Ί Skills β€Ί Prediction Market Trader
πŸ¦€ ClawHub

Prediction Market Trader

by @merjua14

Prediction market trading toolkit for Kalshi. Includes API authentication (RSA-PSS signatures), market scanning, Sofascore tennis de-vigging, true probabilit...

Versionv1.0.0
Downloads886
#security#legal
TERMINAL
clawhub install prediction-market-trader

πŸ“– About This Skill

name: prediction-market-trader description: Prediction market trading toolkit for Kalshi. Includes API authentication (RSA-PSS signatures), market scanning, Sofascore tennis de-vigging, true probability calculation, Kelly criterion sizing, and order execution. Use when trading on Kalshi, analyzing prediction market odds, calculating expected value, de-vigging bookmaker odds, sizing bets with Kelly criterion, or building prediction market bots.

Prediction Market Trader β€” Kalshi Trading Toolkit

Trade prediction markets with edge. Scan markets, calculate true probabilities, size positions, execute orders.

Pipeline

1. Scan β€” Pull open markets from Kalshi API by category (sports, weather, politics, economics) 2. De-vig β€” Get bookmaker odds from Sofascore, remove vig to find true probabilities 3. Compare β€” Find gaps between Kalshi price and true probability (minimum 4% edge) 4. Size β€” Quarter-Kelly criterion for position sizing (max 15% of bankroll per trade) 5. Execute β€” Place limit orders via Kalshi API with RSA-PSS authentication 6. Monitor β€” Track positions, P&L, and exit on profit targets

Requirements

  • Kalshi API credentials β€” KALSHI_KEY_ID and KALSHI_PRIVATE_KEY (RSA private key, inline or .pem)
  • Node.js 18+ β€” for crypto.sign with RSA-PSS

    • Quick Start

    # Set credentials
export KALSHI_KEY_ID=your_key_id
export KALSHI_PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\n...\n-----END RSA PRIVATE KEY-----"
    Scan for edges
    
node scripts/scan-edges.js --category tennis
    Place a trade (dry run)
    
node scripts/trade.js --ticker KXATPMATCH-26MAR12DRAMED-DRA --side yes --price 38 --count 10 --dry
    Check portfolio
    
node scripts/portfolio.js

    Kalshi API Authentication

    Kalshi uses RSA-PSS signatures. The signing message is: timestamp + method + path (NO request body in signature).

    const crypto = require('crypto');
const timestamp = Math.floor(Date.now() / 1000).toString();
const message = timestamp + 'GET' + '/trade-api/v2/portfolio/balance';
const signature = crypto.sign('sha256', Buffer.from(message), {
  key: crypto.createPrivateKey(privateKey),
  padding: crypto.constants.RSA_PKCS1_PSS_PADDING,
  saltLength: 32
});

    Headers: KALSHI-ACCESS-KEY, KALSHI-ACCESS-TIMESTAMP, KALSHI-ACCESS-SIGNATURE (base64)

    De-Vigging Methodology

    Bookmaker odds include a margin (vig). Remove it to find true probabilities:

    implied_prob_A = 1 / decimal_odds_A
implied_prob_B = 1 / decimal_odds_B
total = implied_prob_A + implied_prob_B  (always > 1.0)
true_prob_A = implied_prob_A / total
true_prob_B = implied_prob_B / total

    Kelly Criterion Sizing

    edge = true_probability - kalshi_price
odds = (1 / kalshi_price) - 1
kelly_fraction = (true_prob * odds - (1 - true_prob)) / odds
position_size = kelly_fraction * 0.25 * bankroll  (quarter-Kelly)

    Constraints: max 15% bankroll per position, min 4% edge to trade.

    Scripts

  • scripts/kalshi-auth.js β€” Kalshi API client with RSA-PSS authentication
  • scripts/scan-edges.js β€” Scan markets and compare to Sofascore de-vig
  • scripts/trade.js β€” Place/cancel orders with safety checks
  • scripts/portfolio.js β€” Check balance, positions, P&L

    • References

  • references/market-categories.md β€” Kalshi series tickers and best edge sources
  • references/risk-rules.md β€” Position sizing rules and risk management
  • references/lessons-learned.md β€” Common mistakes and how to avoid them

    • Key Insights (Battle-Tested)

  • Tennis qualifying/challengers = best edge source (5-40% EV gaps)
  • NBA/NHL live markets = 1Β’ spreads, zero edge. Don't bother.
  • NCAAB small conference tournaments = 4-9% EV
  • Indian Wells main draw = efficiently priced (within 1-3% of books)
  • Live edges close in 2-3 minutes β€” speed matters
  • Weather markets = high variance, NWS data helps but forecasts shift
  • Always match Odds API outcomes by name, NEVER by array index

    • πŸ’‘ Examples

    # Set credentials
export KALSHI_KEY_ID=your_key_id
export KALSHI_PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\n...\n-----END RSA PRIVATE KEY-----"
    Scan for edges
    
node scripts/scan-edges.js --category tennis
    Place a trade (dry run)
    
node scripts/trade.js --ticker KXATPMATCH-26MAR12DRAMED-DRA --side yes --price 38 --count 10 --dry
    Check portfolio
    
node scripts/portfolio.js