Bitcoin is the most battle-tested way to fund a Duel account. Deposits credit after network confirmation and withdrawals are processed instantly on Duel’s side — the only wait is the BTC network itself (typically ~10 minutes per confirmation). Minimums are $5 both ways, Duel adds no fees of its own, and no routine KYC is required. If you value maximum liquidity and the deepest exchange support over raw speed, BTC is the default choice; if you want near-instant cash-outs, Litecoin or Solana settle faster.