PolyHeat — Polymarket Heatmap

Interactive stock-market-style treemap heatmap of Polymarket. See where volume and money are flowing in real time.

You are scrolling Polymarket again. Hundreds of markets open across fifteen tabs. Still no idea where the real action is. Every prediction market trader knows this feeling. The interesting markets are buried three screens deep. By the time you finally click into the one that moved, the move is already priced in and someone else took the edge. That part is fixable. WHY READING POLYMARKET IS HARD Prediction markets are information-dense by design. A single event page shows you a question, a probability chart, an order book, and a list of sub-outcomes. Useful at the individual level. Useless when you need to know what is happening across the whole platform. - You cannot see volume distribution across 50 markets simultaneously - You cannot tell which YES prices moved in the last few minutes - You cannot compare activity between a 50 million dollar market and a 500 thousand dollar market at a glance - The default Trending list is sorted but not visualized, so everything looks the same weight Most people either stick to the five markets they already follow or miss opportunities entirely. Both are losing strategies in a market where attention is the edge. PolyHeat is built for the second problem. WHAT POLYHEAT DOES PolyHeat is a stock-market style treemap heatmap for Polymarket. The top active markets are laid out as rectangles. Bigger rectangle means more dollar volume. Color shows you whether the crowd is pricing the market as a likely YES or a likely NO. One glance tells you where the money is flowing and which direction sentiment is pushing. No dashboards. No spreadsheets. No API keys. No account. Open the side panel, look at the grid, click any rectangle to jump straight to that market on polymarket.com. Here is what you get: 24H VOLUME VIEW — The default layout. Top 50 markets ranked by dollar volume over the last 24 hours. Politics, crypto, sports, culture, policy — everything that is actually moving, in one screen. 7D VOLUME VIEW — Same treemap, weighted by 7-day volume instead. This is how you tell a one-day flash event from a sustained build-up. 30D VOLUME VIEW — Weighted by 30-day volume. Shows you the structurally important markets of the month, not just the noisy ones. GAINERS — Markets where the YES price ticked up since the last snapshot. Sorted by biggest move. Useful for catching momentum before mainstream headlines pick it up. LOSERS — Same logic in reverse. Markets where the YES price dropped the most since the last snapshot. Useful for spotting overreactions and fade setups. COLOR INTENSITY YOU CAN READ AT A GLANCE — Green rectangles mean high YES probability. Red means low. Gray means contested 30 to 70 range. Darker shade means stronger conviction. No legend needed after five minutes of use. HOVER TOOLTIP WITH EVERYTHING — Put your cursor on any rectangle and you see the 24h volume, 7d volume, liquidity, current YES price, price change since the last snapshot, and number of sub-markets in the event. Zero extra clicks. CLICK TO OPEN — Click any rectangle and the event opens in a new tab on polymarket.com. Two clicks from "something is moving" to "I am on the order book." SIDE PANEL OR FULL PAGE — The side panel stays pinned while you browse anything else. One button expands it to a full-page view when you want the big picture or a clean screenshot. AUTO-REFRESH EVERY 60 SECONDS — You do not have to do anything. The grid stays current while you work. HOW IT WORKS 1. Install the extension. The icon shows up in your toolbar. 2. Click the icon. The PolyHeat side panel opens on the right side of your browser. 3. The grid loads in under 2 seconds — top 18 markets by 24h volume. 4. Click any tab at the top to switch between 24h, 7d, Gainers, or Losers. 5. Click any rectangle to open that market on polymarket.com. 6. Click the expand arrow in the top-right of the side panel if you want the full-page view with 50 markets and three volume timeframes. That is it. No signup. No API key. No settings to configure. WHY A SIDE PANEL AND NOT A POPUP Popups close the second you click anywhere else. That makes them useless for monitoring. You cannot watch a market heatmap if looking at Twitter kills the heatmap. The side panel stays pinned to your browser window regardless of which tab you are on. Scroll X in the main area, glance at PolyHeat on the side, click through when something catches your eye. It is built for ambient awareness, not one-off lookups. The full-page view exists for a different job — deep analysis and screenshot-ready visuals. Same data, bigger canvas, cleaner framing. HOW GAINERS AND LOSERS ARE COMPUTED Polymarket does not expose a public "price change" field. PolyHeat builds it locally. Every 2 minutes the extension fetches current prices for the top 100 active markets and stores them in your browser local storage. On the next fetch, it compares the new prices against the stored ones and calculates the delta. Markets with a positive delta show up under Gainers. Negative deltas show up under Losers. The size of each rectangle still reflects 24h volume, so you see momentum weighted by liquidity. A 5-point move in a 10 million dollar market matters more than a 15-point move in a 20 thousand dollar ghost market. The treemap makes that obvious without you having to think about it. The snapshot lives only in your browser. Nothing leaves your machine beyond the single read from Polymarket's own public API. REAL SCENARIOS WHERE THIS HELPS Morning routine: You open your browser at 8 AM. Click PolyHeat. In three seconds you know which three markets moved overnight while you were asleep. No need to scroll the Polymarket trending page or dig through Discord channels. Event-driven trading: A headline drops about a Fed rate decision. You want to see every Polymarket contract related to rates. Open the Gainers tab — the contracts that actually moved in the last few minutes are sorted to the top and sized by liquidity. You find the most tradeable one in 5 seconds. Volume vs velocity read: A sports market shows up huge on the 24h volume view but does not appear under Gainers or Losers. That tells you the money is flowing but the consensus is not shifting — a sign the market is efficient and unlikely to reprice soon. Save your capital for something with an actual opening. Catching fade candidates: Scan the Losers tab. An election market dropped 8 percentage points on modest volume. Click into the event. If the drop looks overreactive relative to the news, you know where to look for a fade entry. Screenshot for a thread: Click the expand button in the side panel. Full-page view loads in a new tab. Take a screenshot of the grid. Post to X. The visual carries itself — no caption needed beyond the date and a one-line take. Research across timeframes: Toggle between 24h, 7d, and 30d views on the same set of markets. The ones that stay big across all three are the structurally important events of the month. The ones that only appear in 24h are the day's flash stories. Two clicks, two completely different pictures. Watching a niche vertical: You care mostly about crypto markets. Open the full-page view, and the BTC and ETH price contracts are usually the biggest green squares in the top-left. You know exactly where to look without searching. THE DATA BEHIND THE GRID Every data point in PolyHeat comes from Polymarket's public Gamma API — the same API their own website uses. No scraping. No reverse-engineered endpoints. Just a single GET request to: gamma-api.polymarket.com/events The response includes titles, 24h/7d/30d volumes, liquidity, and current YES/NO outcome prices for every active event. PolyHeat transforms that array into a D3.js treemap and renders it with area proportional to volume and color proportional to probability. No pricing models. No hidden assumptions. What you see is what Polymarket reports. WHAT THIS EXTENSION DOES NOT DO - It does not read your Polymarket account, wallet address, or any on-chain data - It does not track you, inject ads, run analytics, or send any data to any third-party server - It does not modify polymarket.com or any other website — no content scripts, no DOM injection - It does not require an account, login, or API key The only permissions it uses: - storage — to save the local price snapshot so velocity calculations work across refreshes - alarms — to refresh the snapshot in the background every 2 minutes so Gainers and Losers data is ready the moment you open the side panel - sidePanel — to show PolyHeat next to your browser window instead of in a dismissable popup - host permission for gamma-api.polymarket.com — the single public API endpoint the extension fetches from That is the entire permission list. No analytics. No telemetry. The extension makes one outbound request, to Polymarket's own public API, and nothing else leaves your browser. FREE TO USE All features are available at no cost. Side panel, full page, all five view modes, velocity tracking, hover details, click-to-open — everything. No account. No paywall. No usage limits. If the extension ever adds paid features in the future, they will be additive. The current functionality stays free. WHO THIS IS FOR - Polymarket traders who want situational awareness across the whole platform at a glance instead of opening markets one by one - Journalists and analysts covering prediction markets who need a clean visual of where capital is flowing - X and Twitter users who want to share Polymarket activity without cobbling together 20 separate screenshots - Crypto and DeFi people who already know stock-market heatmaps and want the same mental model for prediction markets - Anyone watching elections, policy outcomes, or major sports events through the prediction market lens Not for: passive observers who just want to see who is favored to win a single race. The Polymarket website already handles that. PolyHeat is for people who care about flow, not snapshots. GETTING STARTED Install the extension, click the icon, and the grid loads in under 2 seconds. The first snapshot kicks off immediately in the background, so Gainers and Losers data starts populating within the first minute. No account. No signup. No credit card. Just open the panel and look at the grid.