Positions
Each open position reports its size, entry value, live valuation, margin, and PnL:
Stream them on the Positions Stream or
fetch them via Get Positions. See
Position Metrics for how entry value, notional
value, unrealized PnL, and break-even are derived, and
Margin & Liquidation for how margin is
sized.
Account Summary
Your account-wide balances, margin usage, and PnL are available on the Account Summary Stream and via Get Account Summary:
See Account Equity & Balances for how equity,
available balance, and the margin ratios are derived.