Priced from live exchange data, with no replay and no delay
Every paper position is valued from the live public market data of the exchange you select: WOO X, Binance, Bitfinex or Bitkub. There is no recorded price series and no delay, so a paper bot reacts at the same moments a bot reading that exchange's feed would.
A paper order never reaches the exchange's order book. It cannot move the price, and nobody trades against it. On a heavily traded pair that difference is small. On a thinly traded one it can be large, and no paper engine anywhere can tell you how large.
How a paper order fills
A market order fills at once, in full, at the current live price, and pays the exchange's taker rate. A limit order waits in your paper account. When the live price reaches it, it fills in full at its own limit price and pays the maker rate.
Live trading is less tidy. A real market order on a thin book can fill across several prices. A real limit order waits in a queue, and may fill in parts or not at all when price only touches it. Paper results therefore lean to the generous side, and they are best read that way.
Fees at each exchange's published rates
Every paper fill is charged the maker or taker rate of the exchange you picked, not one house figure. Binance is charged 0.10%, Bitfinex nothing, and Bitkub 0.25% on THB-quoted pairs against 0.10% on USDT-quoted ones.
That changes which setups make sense. A grid whose rungs sit closer together than one buy fee plus one sell fee spends every swing on fees first, and a paper engine that charged nothing would hide it completely.
Pick a starting balance, and reset it whenever you like
You choose a starting balance of $10,000, $50,000, $100,000 or $1,000,000 when you set up. Size matters in practice: a strategy that splits $10,000 across fifty orders works in $200 orders, and the same strategy on a million works in $20,000 ones. Practicing at the size you have in mind keeps the numbers you watch familiar.
A reset returns the balance to its starting figure and stops every bot attached to it, deliberately. A bot left running across a reset would keep acting on a position that no longer exists.