The PolySmarter browser extension
PolySmarter is a read-only research panel that opens beside a Polymarket market page. It reads the same public data as this site and shows the same readings — the settlement rules, the visible book, and what a size you choose would cost to fill — next to the market you are already looking at, instead of in another tab.
What it shows
Three questions, which are the same three this site answers:
- What you are actually betting on. The market’s own settlement rules, with the condition that triggers the payout, the deadline, the source that decides it, and the exceptions — plus a note when the rules text itself has changed. Why the rules paragraph is the thing to read.
- What it would cost. The headline probability is a mid-price, not a fill. The panel walks the order book that is visible at that moment for the side and size you pick, and reports the average price you would pay, the worst price you would touch, how much of the visible depth you would use, the fee where the venue publishes one, the all-in cost, and the price at which the position breaks even. It will also work backwards to the largest size that still fits a cost limit you set. How that differs from the screen price.
- What has been happening. Recent aggressive buying and selling, how wide the spread has been, how tradable the market is, and the other outcomes of the same event.
It can also hold a watch on a market — a price, a spread, a depth level, a breakeven, or a change to the rules text — and tell you when the market crosses it.
It is the same reading as this site
Not a similar one. The panel on a market page here and the panel in the extension are the same code over the same server-side builder, held in step by a check that compares the two copies file by file rather than by anyone remembering to carry a fix across. A figure you read here and the same figure in the extension come from one implementation, so they cannot quietly disagree — which matters most for the execution arithmetic, where two copies of one fee formula would be two chances to differ.
The coverage limits are also the same. Order books and the trade tape are recorded for a tracked subset of Polymarket, so on a market outside that subset the panels that need recorded history say they have no coverage for it rather than filling in something plausible. What each kind of nothing means.
What it reads
- Which Polymarket page is open, so it knows which market to look up. It runs on Polymarket pages and nowhere else — it is not loaded on any other site.
- Our own API, which is where every figure it draws comes from.
- Your settings, kept in your own browser: the side and size you last used, the panel language, and any watch you have set.
What it does not do
PolySmarter is analytics only. It does not connect to a wallet, hold or transmit funds, or place, route, change or cancel an order. It cannot read your Polymarket account, your balance, your positions or your trading history — it has no way to see any of them. Nothing it shows is a probability forecast, a trading signal, or investment, financial, legal or tax advice, and every figure describes public data that already exists. What this is, and what it is not.
PolySmarter by Yield3 is not affiliated with, endorsed by or sponsored by Polymarket.
Free and Pro
The settlement rules, the visible book, what a fill would cost and the recent activity all need no account. A Pro subscription adds four things on top: the participant table, how concentrated the trading has been, the live trade tape, and the information timeline. Pro is used in the extension, which signs in on its own site. What Pro costs and what it adds.
On this website those same Pro modules are locked for everybody, subscribers included, because this site has no sign-in yet.
How to get it
There is no install link on this page. We would rather send you to the listing ourselves than publish an address here that could go stale or point at something that is not ours — ask through support and we will reply with it.