Analytics & datadashboardfree
DefiRate prediction market volume tracker: what it does, what it costs, where it stops
Last checked 2026-09-08
DefiRate publishes a free volume tracker for Kalshi and Polymarket with daily updates and a CSV export on every chart. The headline at fetch was $13.9B of weekly notional volume, split 86% Kalshi ($11.9B) and 14% Polymarket ($2.0B), with Polymarket US at $5.9M.
It answers venue-level questions: who is taking share, which categories are moving and how volume has trended over weeks and months.
What it does
Four headline measures: weekly notional volume ("Total USD value of contracts traded during the last complete calendar week"), active markets (345,135 at fetch), weekly transactions (84,177,626) and open interest ($1.5B).
Category tables compare Politics, Sports, Crypto, Economics, Finance, Tech, Culture, Weather, Misc and World across 24h, 7d and 30d windows for each venue.
Rolling change figures sit next to each venue. At fetch, Kalshi was down 10.5% over 24 hours and up 2.1% over 7 days; Polymarket was up 359.7% over 24 hours and down 50.0% over 7 days, which shows how noisy the short windows are.
- Per-venue pages: Kalshi and Polymarket, plus Sports, Crypto and Politics trackers
- Kalshi page adds monthly volume with YTD cumulative, weekly volume, a daily fee estimate table and Kalshi vs Polymarket share
- Display figures round to the nearest $10M; the CSV files are unrounded
Pricing
Free, with no paywall or login.
Venues and data
Kalshi, Polymarket and Polymarket US. The Kalshi page states volume is pulled from Kalshi's public API and that dollar volume is contracts times price paid, not open interest or fees. Charts update daily; weekly figures are finalized and locked each Sunday.
The Kalshi page at fetch showed $334.40M of volume for the day, $40.02B for the current month and $179.61B year to date, with Kalshi holding 84.0% of the current month's share against Polymarket.
Where it falls short
Venue and category level only. There is no per-market chart or order book view.
Daily granularity. Intraday moves are not visible.
The Kalshi fee table is an estimate computed by DefiRate, not a number published by the exchange.
DefiRate also publishes Fed odds pages and calculators; those are separate tools with their own pages in this directory.
Who should use it
Anyone who needs a citeable weekly volume or market-share figure with a downloadable CSV. Traders working a single market should use a venue-native chart.
Questions about DefiRate prediction market volume tracker
Is the DefiRate prediction market volume tracker free?
Yes. There is no login or paywall, and each chart has a CSV export.
How often does DefiRate update Kalshi and Polymarket volume?
Daily. Weekly figures are finalized each Sunday and locked.
Where does DefiRate get Kalshi volume data?
From Kalshi's public API, per the methodology note on the Kalshi page. Volume is contracts traded multiplied by price paid.
Trackers find the edge. Calculators size it. Alerts time it.
When it is time to execute, the free Kairos terminal trades Kalshi, Polymarket and Predict.fun from one book.