STX is an exchange, not a sportsbook. There is no house price to take: every price on the book was put there by another participant, and you can put your own there too.
That changes what you need to understand before writing code. These pages cover the model the API is built on. Read them in order if you are new to the exchange, or jump to whichever one your current question belongs to.
Start here
Section titled “Start here”United States and CanadaTwo exchanges under different regulators. Which one you integrate with changes almost everything, and accounts do not carry across.
How markets workBinary contracts that settle at $1 or $0, what a price means, and how to read a market's status.
Trading
Section titled “Trading”Order typesLimit and market orders, how each fills, and what happens to the quantity that does not.
Positions and liabilityOrder liability, position liability, and why filling an order can increase your available balance.
Settlements and payoutsWhen a settlement is created, the fields it carries, and how profit and loss is computed.
Market symbolsHow to read a symbol, and how to map STX markets onto a universe you already track without a lookup.
Market and order statusThe seven market statuses and the nine order statuses, which are terminal, and which transitions are possible.
Combos (preview)An upcoming feature: one contract across several markets, priced by request for quote. Not available to try yet.
Constraints on your account
Section titled “Constraints on your account”Account limitsCeilings on order liability and exposure. They surface as a rejected order rather than an error about limits.
Rate limitsWhat is enforced today, and how to build so that future limits are a non-event.
Once the model makes sense, Quick Start takes you from creating an API key to a resting order and a live feed of your own fills.