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PolySniper - Polymarket Arbitrage
Summary: Spot price gaps before they close
Stop Missing Risk-Free Profits on Polymarket
You've done the research. You understand prediction markets. You know that when the sum of all Yes prices in a multi-outcome market drops below $1.00, there's free money on the table. But by the time you manually check ten different outcomes, pull out your calculator, and verify the math—the opportunity is gone. Market makers are fast. You're not a machine.
PolySniper changes that.
The Problem Every Polymarket Trader Faces
Polymarket hosts hundreds of active markets at any given time. Many of these are multi-outcome events: elections with multiple candidates, sports tournaments, award shows, or geopolitical scenarios with several possible results. These markets use a "negative risk" structure where all outcomes are mutually exclusive—exactly one will resolve to $1.00, the rest to $0.00.
Here's where it gets interesting. In theory, the Yes prices across all outcomes should sum to exactly $1.00. In practice? They often don't. Liquidity imbalances, slow arbitrageurs, news events, and simple market inefficiency create gaps. When the total cost to buy Yes on every outcome drops below $1.00, you can lock in a guaranteed profit regardless of which outcome wins.
The challenge is finding these opportunities before they vanish.
Consider a presidential primary with 8 candidates. To check for arbitrage manually, you need to:
Multiply this process across dozens of multi-outcome events. Refresh constantly. Hope you don't make arithmetic errors. And somehow do this faster than professional traders running automated systems.
It's exhausting. It's inefficient. And most of the time, you'll find nothing—because arbitrage windows close within seconds, not minutes.
How PolySniper Works
PolySniper runs quietly in your browser, continuously scanning Polymarket's API for arbitrage opportunities. Every few seconds, it analyzes all active negative-risk events, calculates the total cost to buy all Yes positions, and identifies markets where that sum falls below $1.00.
When a gap appears, you'll know immediately.
The extension displays opportunities ranked by APR (annualized percentage return), accounting for how long until the market resolves. A 2% spread on a market closing tomorrow is far more attractive than the same spread on a market closing in six months—and PolySniper surfaces this distinction clearly.
Each signal shows you:
One click takes you directly to the market page where you can execute the trade.
Built for Real Trading Conditions
PolySniper isn't a theoretical tool. It's designed around how Polymarket actually works.
Negative Risk Focus: The extension specifically targets negRisk markets—the multi-outcome events where true arbitrage is possible. Binary yes/no markets don't offer the same structural opportunity, so PolySniper filters them out automatically.
Liquidity Awareness: Finding a 10% spread means nothing if there's only $5 of liquidity. PolySniper evaluates order book depth and surfaces the minimum available liquidity across all legs of a potential trade, so you know the realistic size you can execute.
Smart Filtering: Not every gap is worth your attention. A 0.1% spread generates more transaction costs than profit. Markets with extreme illiquidity may show phantom opportunities that evaporate when you try to trade. PolySniper applies intelligent filters:
Real-Time Updates: Market conditions change constantly. PolySniper refreshes its scan at configurable intervals—as fast as every 5 seconds—so you're working with current data, not yesterday's prices.
Two Ways to Monitor
Floating Panel: When you browse Polymarket, a compact overlay panel appears in the corner of your screen. It shows the current signal count and top opportunities without disrupting your browsing. Drag it anywhere. Minimize it when you need focus. Expand it to see details. Click through to act on opportunities.
Popup Dashboard: Click the extension icon for a full view of all detected signals. See comprehensive statistics, adjust your settings, and review opportunities in a clean, focused interface—even when you're not on Polymarket.
Both interfaces stay synchronized. Spot a signal in the popup? It's already visible on your Polymarket tab.
Customization for Your Strategy
Every trader has different thresholds for what constitutes a worthwhile opportunity.
Minimum APR: Set how much annualized return justifies your attention. Day traders might accept 30% APR on short-dated markets. Conservative traders might want 100%+ before engaging.
Minimum Depth: Filter out thin markets where slippage would eat your profits. Set this based on your typical position size.
Refresh Interval: Balance between catching opportunities quickly and conserving system resources. Aggressive traders scan every 5 seconds. Casual users might prefer 30-60 second intervals.
Whale Mode: Toggle to show only opportunities with $1,000+ capacity—meaningful size for serious traders who don't want to waste time on small-ball plays.
Sound Alerts: Optional audio notifications when new high-value signals appear.
Understanding the Math
For those new to prediction market arbitrage, here's the core concept:
Imagine an event with three possible outcomes: A, B, and C. The current Yes prices are:
Total cost to buy Yes on all three: $0.95
You spend $0.95 to hold one Yes share of each outcome. When the event resolves, exactly one outcome pays $1.00. Your guaranteed profit: $0.05 per set, or 5.26% return.
If the market resolves in 30 days, that's approximately 64% APR.
This is textbook arbitrage: risk-free profit from market inefficiency. The only variables are finding these gaps (hard), acting fast enough (harder), and having sufficient liquidity to make it worthwhile (hardest).
PolySniper handles the first problem. Speed and capital are up to you.
Why Gaps Exist
You might wonder: if arbitrage opportunities are free money, why don't they get instantly eliminated?
Several factors create and sustain these gaps:
Fragmented Attention: With hundreds of active markets, even sophisticated traders can't monitor everything simultaneously. New information might spike one outcome's price while others lag behind.
Capital Constraints: Arbitrage requires buying multiple positions simultaneously. Traders with limited capital might see the opportunity but lack funds to execute all legs.
Transaction Costs: Gas fees, spread costs, and time investment create friction. Sub-1% gaps often aren't worth the effort for manual traders.
Information Asymmetry: When breaking news hits, some outcomes reprice faster than others. The gap between "smart money" and "slow money" creates temporary arbitrage.
Market Maker Inventory: Professional market makers sometimes pull liquidity to manage risk, briefly widening spreads.
PolySniper helps you compete by removing the monitoring bottleneck. The edge goes to whoever acts first—and you can't act on what you don't see.
Privacy and Security
PolySniper operates entirely in your browser. It reads public market data from Polymarket's API—the same data visible to anyone on the website. The extension:
Your trading decisions remain yours. PolySniper provides information; you maintain full control over execution.
Required permissions are minimal:
Limitations and Honest Expectations
PolySniper is a detection tool, not a trading bot. Important caveats:
Opportunities Are Rare: Efficient markets mean arbitrage gaps don't appear constantly. You might see zero signals for days. This is normal—it means the market is working correctly. When gaps do appear, they matter.
Speed Matters: Even with instant detection, you still need to execute manually. Professional arbitrageurs may beat you to thin opportunities. Focus on signals with higher capacity where competition is less fierce.
Prices Change: The prices shown when a signal appears may shift by the time you navigate to the market and place orders. Always verify current prices before trading.
Not Financial Advice: PolySniper provides market data analysis. It does not constitute investment advice. Prediction markets carry risks. Trade responsibly with capital you can afford to lose.
Market-Specific: This extension is purpose-built for Polymarket. It does not scan other prediction markets or asset classes.
Getting Started
No configuration required to start. The extension begins scanning immediately with sensible defaults.
For Serious Prediction Market Traders
If you're actively trading on Polymarket, you understand the value of information edge. PolySniper delivers a specific, quantifiable advantage: the ability to spot arbitrage opportunities that manual monitoring would miss.
You're not competing against the market—you're competing against other traders for fleeting inefficiencies. Every second of delay costs potential profit. Every gap you miss is money left on the table.
PolySniper keeps watch so you don't have to. When opportunity knocks, you'll hear it.
Technical Notes
PolySniper: Because arbitrage rewards the alert.
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