Lighter is a zero-knowledge rollup exchange stack with a matching engine, risk engine, and batch prover that generates SNARK proofs for order matching and liquidations verified on Ethereum. It supports market, limit, stop-loss, take-profit, and TWAP orders, and matches using price-time priority with risk checks after each trade. Funding payments settle hourly and flow peer-to-peer between longs and shorts. Liquidations follow a staged waterfall and use an LLP insurance fund, including partial liquidation and auto-deleveraging. Standard accounts have 0 maker and 0 taker fees.