The internal account that holds a player's balance: deposits, withdrawals, bets, winnings, and bonus funds kept separately, with every movement recorded as an immutable ledger entry.
The wallet is the single place where money correctness is decided. A race condition that lets one balance be spent twice, or bonus funds mixed with real ones, becomes both a financial loss and a licence problem.
We build the wallet as an append-only ledger with transactional guarantees, separate real and bonus balances explicitly, and reconcile against payment providers daily so discrepancies surface the same day.