PolySniper - Polymarket Arbitrage

PolySniper - Polymarket Arbitrage Stop refreshing Polymarket tabs. Start catching the gaps that actually pay. You trade prediction markets. You know how negRisk events work — when the sum of all Yes prices dips below $1.00, there's a guaranteed profit at settlement. The problem is these gaps close in seconds. By the time you manually check the orderbook across 6 or 8 outcomes, the opportunity is gone. Or worse — you spot what looks like a gap, buy in, and realize the mid-price was misleading. The real ask was higher. After fees, there was no edge at all. That's the gap between seeing a price and knowing a price. PolySniper closes it. WHY POLYMARKET ARBITRAGE IS SO HARD TO CATCH NegRisk arbitrage on Polymarket is structurally simple — buy every Yes outcome for less than $1.00 total, collect $1.00 at settlement. But execution is anything but simple. - Mid-prices lie. The prices shown on the Polymarket event page are mid-points between the best bid and best ask. They do not reflect what you actually pay when you hit the ask side of the orderbook. - Fees eat your edge. Polymarket charges fees on net winnings. A spread that looks profitable at 2% might be break-even or negative after fees are deducted. - Multi-outcome events are tedious to scan. A presidential primary market might have 12+ outcomes. Adding up all the Yes ask prices manually — accurately, with real orderbook data — takes longer than the gap lasts. - Volume matters. A 5% spread on a market with $3 of ask-side liquidity is not a real opportunity. You need to know the executable depth before committing capital. Most traders either miss these gaps entirely or learn about them after the fact. Some build custom scripts, but maintaining API integrations across gamma and CLOB endpoints is a project in itself. PolySniper automates the entire detection pipeline so you can focus on execution. WHAT THIS EXTENSION DOES PolySniper is a Chrome extension that continuously scans Polymarket for negRisk arbitrage opportunities. It runs two verification phases — a fast pre-filter using the gamma API, followed by real orderbook verification against the CLOB API — so every signal you see reflects prices you can actually trade at, with fees already deducted. No spreadsheets. No manual price addition. No guessing whether mid-prices represent real asks. Here is what you get: Two-Phase Signal Verification — Phase 1 scans up to 500 events using gamma mid-prices to identify candidates where the total cost might be below $1.00. Phase 2 fetches real orderbook data from the Polymarket CLOB API, walks the ask side of each outcome, and recalculates the spread using actual executable prices. Only signals that remain profitable after the 2% fee buffer are shown. Precise APR Calculation — Every signal displays the annualized return based on actual spread, days to expiry, and fee-adjusted cost. The formula is transparent: ROI = spread / totalCost, APR = (ROI / daysLeft) x 365 x 100. No hidden rounding. Real Orderbook Depth — For each outcome in a signal, you see the volume-weighted average price and executable USD depth from the CLOB orderbook. You know exactly how much capital the opportunity can absorb before the price moves. Verification Badges — Signals verified against real CLOB orderbook data show a green checkmark. If the CLOB was temporarily unreachable for any outcome, the signal is marked with a yellow indicator and labeled as mixed or gamma-only, so you know the confidence level. On-Page Floating Panel — When you browse polymarket.com, a draggable panel shows live signals directly on the page. Click any signal to jump to that market instantly. Desktop Push Notifications — Pro users receive Chrome desktop notifications when a new signal meets their minimum APR threshold. Click the notification to open the market page directly. Whale Detection Filter — Focus on opportunities with meaningful liquidity. The whale filter highlights signals with $1,000+ in executable depth, so you skip thin markets. HOW IT WORKS 1. Install the extension from the Chrome Web Store. 2. Open the popup or visit polymarket.com — scanning starts automatically. 3. Signals appear ranked by APR, with spread, ROI, days left, and depth data. 4. Click any signal to open the Polymarket event page and execute your trade. 5. Adjust minimum APR, depth thresholds, and refresh interval in Settings. That is it. No account required for the free tier. No API keys to configure. The extension handles all data fetching in the background. WHY A TWO-PHASE PIPELINE A single-pass scanner using gamma API prices would be faster, but it would also produce false positives. Gamma mid-prices are derived from the midpoint of the bid-ask spread — they do not represent the actual cost of buying the Yes outcome. The two-phase approach solves this. Phase 1 is cheap and fast — it pre-filters hundreds of events in one API call and typically narrows the field to 0-5 candidates. Phase 2 only fires for those candidates, fetching real orderbooks from the CLOB API in a single batch request. This keeps network usage minimal while ensuring every signal is backed by real executable prices. If the CLOB API is temporarily unavailable, PolySniper falls back to gamma-based signals with a clear warning label — so you are never left with zero data. SIGNAL HISTORY AND SETTINGS Configurable Refresh Interval — Free users scan every 60 seconds. Pro users can set intervals as low as 5 seconds for near real-time detection. Sound Alerts — Enable audible alerts in Settings to get notified without watching the popup. Available for Pro users. Custom Thresholds — Set your minimum APR (default: 50%) and minimum depth (default: $10 USD) to filter out noise. Only signals meeting both thresholds appear in your feed. All settings are stored locally using Chrome's storage API. Nothing is sent to any external server beyond the Polymarket data APIs and the token verification endpoint. REAL SCENARIOS WHERE THIS …