Units and prices
Every number in the API is a whole number. Each kind has its own unit.
Prices
Section titled “Prices”A price is in basis points of $1, from 1 to 9,999. 5500 is 55¢.
A price is always for the outcome named beside it. Markets trade on a grid of
100 basis points (1¢), so an order at 5550 is rejected with price_off_tick.
Quantities
Section titled “Quantities”A quantity is in lots. 100 lots make one share, and a share pays $1.00 if its outcome wins. So 250 lots is 2.50 shares. If a market is void, a share pays $0.50 on either outcome. See A void market.
Money is in units: 1,000,000 to the dollar. Balances, costs, payouts and profit and loss all use them.
Buying quantity lots at price_bps costs price_bps × quantity units. One lot
pays 10,000 units if it wins. For example, 100 lots of Up at 5,500 costs 550,000
units ($0.55) and pays 1,000,000 units ($1.00) if Up wins, or 500,000 units
($0.50) if the market is void.
One book per market
Section titled “One book per market”Each market has a single order book, seen from both sides. A bid for Up at 5,500 is an ask for Down at 4,500: both sides together pay out exactly $1.00. So your order for one outcome can fill against someone’s order for the other.
The market data socket sends the book with Up prices only. To read it for Down, subtract each price from 10,000 and swap the bids and asks. See Read prices.
Selling what you don’t hold
Section titled “Selling what you don’t hold”Selling (side: "ask") an outcome you don’t hold leaves you short: if it wins,
you owe 10,000 units a lot. So an ask needs collateral of (10000 - price_bps) × quantity
units, the most it can lose. Every order is checked against your account’s
worst case before it reaches the book. See Orders.
Times are epoch milliseconds (_ms fields), except the account history’s
created_at, traded_at and settled_at fields, which are UTC text:
2026-09-29 14:05:00.