Taker Fee
The fee charged to the order-taker side of a trade on Polymarket, calculated as a function of shares, price, and market type.
Definition
The taker fee on Polymarket is computed as: shares × feeRate × price × (price × (1 − price))^exponent. For 5-minute and 15-minute crypto binaries the parameters are feeRate = 0.25 and exponent = 2, which causes the fee to peak near 1.56% at p = 0.50. Sports markets use feeRate = 0.0175 and exponent = 1, peaking near 0.44%. Maker orders pay 0% fee.
In practice
Fee drag is the primary enemy of scalping strategies. A bot buying YES at $0.50 and selling at $0.52 on a crypto binary pays roughly 1.56% in fees each way, meaning the 2-cent move is consumed almost entirely by costs. Predtools bots verify the exact fee rate per market using GET https://clob.polymarket.com/fee-rate?token_id={token_id} before entering a position, because rates can differ from the defaults. Factoring both entry and exit fees into the breakeven price is mandatory before placing any taker order.