Best Prediction Market Arbitrage Bots 2026: Cross-Platform Arb Ranked

Cross-platform arbitrage is the most mathematically rigorous strategy in prediction markets. When the same event is priced differently on Polymarket vs. Kalshi — or on prediction markets vs. sportsbooks — you can lock in guaranteed profit regardless of the outcome. The challenge is execution: finding spreads fast, executing both legs reliably, and accounting for fees on every platform.

This guide ranks the best cross-platform arbitrage bots and tools available in 2026.

For platform-specific arb bots, see Best Arbitrage Bot for Polymarket and Best Arbitrage Bot for Kalshi.

Three Types of Prediction Market Arbitrage

1. Cross-Platform Arb (Polymarket ↔ Kalshi)

The same event priced differently across platforms. Most consistent edge in 2026.

Example: “Will the Fed cut rates in March?”

• Kalshi YES price: 62¢ → Kalshi NO price: 38¢
• Polymarket YES price: $0.57 → Polymarket NO price: $0.43

Buy YES on Polymarket ($0.57) + Buy NO on Kalshi (38¢ = $0.38) = $0.95 total cost. One of them pays $1.00. Guaranteed $0.05 profit (5.3% return) before fees.

2. Prediction Market ↔ Sportsbook Arb

When prediction market odds diverge from sportsbook lines on the same event (common in sports markets).

3. Intra-Platform Arb

Within a single platform — correlated markets diverging, or YES+NO mispricing. Thinnest spreads, highest competition.

Quick Rankings

How Cross-Platform Arb Works

Price Normalization

The first challenge is comparing prices across platforms with different formats:

def normalize_price(polymarket_price=None, kalshi_price=None):
    """Convert to common 0-1 probability format."""
    if polymarket_price is not None:
        return polymarket_price       # Already 0.00-1.00
    if kalshi_price is not None:
        return kalshi_price / 100     # Convert cents to 0.00-1.00

Edge Calculation After Fees

A raw spread means nothing without accounting for fees:

def calculate_arb_edge(yes_price_a, no_price_b, fee_a=0.02, fee_b=0.02):
    """Calculate arbitrage edge after platform fees."""
    cost_yes = yes_price_a * (1 + fee_a)
    cost_no = no_price_b * (1 + fee_b)
    total_cost = cost_yes + cost_no
    payout = 1.00  # Winner pays $1.00
    edge = payout - total_cost
    roi = edge / total_cost * 100
    return {"edge": edge, "roi_pct": roi, "total_cost": total_cost}

For live arb detection, use the Cross-Market Arb Finder or the Arbitrage Calculator.

Detailed Reviews

1. PolyArb Pro

The fastest cross-platform arb scanner, monitoring Polymarket and Kalshi in real-time via WebSocket feeds.

Strengths:

• Sub-second detection via WebSocket streams on both platforms
• Automatic price normalization and fee-adjusted edge calculation
• Configurable minimum edge thresholds (default: 2% after fees)
• Position limits and risk controls per market
• Dashboard with real-time arb heatmap

Limitations:

• Monthly subscription ($149-399/mo) reduces net profitability on thin spreads
• Requires funded accounts on both platforms
• No sportsbook integration

Best for: Serious cross-market arb traders who want the fastest detection and reliable execution.

2. CrossMarket Agent

The widest platform coverage, scanning Polymarket, Kalshi, and sportsbook odds.

Strengths:

• Three-way arb scanning: Polymarket ↔ Kalshi ↔ sportsbooks
• Uses OddsPapi data for sportsbook integration
• One-time purchase ($500) — no recurring fees
• Self-hosted for maximum control and latency optimization

Limitations:

• Requires technical setup (Python environment, API keys for each platform)
• Sportsbook execution is manual (alerts only) — auto-trade only on Polymarket/Kalshi
• Learning curve for configuration

Best for: Developers who want maximum flexibility and the widest opportunity set.

3. ArbScanner

Mid-tier scanner with good detection and an alert-only mode for manual execution.

Strengths:

• Clean dashboard with visual arb identification
• Alert-only mode (email, Telegram, Discord) for manual traders
• Good documentation and onboarding
• Budget-friendly at $79-199/mo

Limitations:

• Slightly slower than PolyArb Pro on detection
• Limited risk management features compared to premium options
• No sportsbook integration

Best for: Traders who want to verify arbs manually before executing, or who prefer a lower price point.

4. SpreadHunter

Focused on intra-Polymarket arbitrage — correlated market divergence and YES+NO mispricing.

Strengths:

• Deep Polymarket-specific analysis
• Correlation detection between related markets
• One-time purchase ($299)
• Clean codebase for customization

Limitations:

• Polymarket-only — no cross-platform arb
• Intra-market spreads are thin and competitive
• Requires significant capital for thin-spread strategies

Best for: Technical traders focused exclusively on Polymarket who want intra-platform spread capture.

5. OctoBot (Arb Module)

Open-source trading bot with a community-built arbitrage plugin.

Strengths:

• Free base version with open source code
• Active community with regular updates
• Visual configuration interface
• Extensible to other platforms via plugins

Limitations:

• Arb detection is slower than dedicated scanners
• Limited Kalshi integration compared to Polymarket
• Community-maintained — quality varies by plugin

Best for: Developers who want to experiment with arb strategies without upfront cost.

Capital Requirements

See Also

• Best Arbitrage Bot for Polymarket — Polymarket-specific arb rankings
• Best Arbitrage Bot for Kalshi — Kalshi-specific arb rankings
• Cross-Market Arbitrage Guide — Strategy deep-dive
• Cross-Market Arb Finder Tool — Live arb scanner
• Arbitrage Calculator — Calculate edge and stake splits
• Prediction Market API Reference — API documentation for both platforms
• Agent Betting Glossary — Key terms defined
• Agent Marketplace — Browse and compare all agents

Rankings updated March 2026. Not financial advice. Built for builders.