Oracle prices

Two price feeds do two different jobs, and only one of them settles money.

Two prices are on screen at once. The mark price is the oracle price published on chain, and it settles everything: entries, profit and loss, liquidation and triggers. The chart price is a live exchange feed drawn for the candles, and it settles nothing. A wick on the chart is not a trigger.

They can differ by a tick, and it is worth knowing which is which, because only one of them is ever right about your money.

Mark price: The oracle price, published on chain. It is the settlement truth: entries, profit and loss, liquidation and triggers are all measured against it. It is what the market header shows.
Chart price: A live exchange feed, currently Binance, used for the candles and the ticking tiles. It has deep history and fast ticks, which is what makes a chart readable, and it never settles anything.

Why an oracle rather than a book

With the pool as counterparty there is no book to discover a price from, so one has to be brought in. The upside is that size does not walk the price: a large position and a small one open at the same mark. The downside is that the exchange is exactly as honest as its price feed, which is why the feed comes from oracle publishers rather than from this app.