About Courtside
Courtside compares NBA prediction-market prices on Kalshi and Polymarket with margin-removed sportsbook fair value, so you can see where the same game is priced differently and how much of that gap survives fees and available liquidity.
What Courtside does
For every NBA game with an exchange contract, Courtside lines up the Kalshi and Polymarket order books, the sportsbook consensus price with the bookmaker margin removed, and the history of each price. It reports differences after modeled exchange fees, shows how much size is available at the quoted price, and flags stale quotes and contracts whose settlement rules do not match.
Courtside is a research tool. It does not place orders or wagers, hold funds, or guarantee that a displayed price can be filled.
Where the data comes from
- Kalshi and Polymarket order books, read from each exchange’s public market data feeds.
- Sportsbook prices from The Odds API, combined into a margin-removed consensus.
- NBA schedules and game status from BALLDONTLIE.
Every number on the board shows when it was observed. The methodology page explains how fair value, fees, depth and settlement matching are calculated.
How Courtside makes money
- Pro subscriptions. Free users see every market; Pro unlocks every after-fee price gap, full order-book depth, complete price history and more alerts.
- Sponsored referral links. Trade buttons and promo codes for Kalshi and Polymarket are sponsored. If you open an account through them, Courtside may earn a commission. These links are labeled wherever they appear.
Editorial independence
Referral relationships do not change what the board shows. Prices, fair values and gaps are calculated the same way for every venue, and a venue with a sponsored link is not ranked above one without. When the data for a game is missing or stale, Courtside says so instead of filling the gap.