Qume Basics

Self-Trading: In order to protect users from paying unnecessary fees to the exchange, self-trading is not allowed. In the event of a self-trade, the taker order will be rejected and the maker order will not be affected.

Trading Fees: Qume uses a maker-taker fee model. Each executed order incurs a trading fee. 

• "Maker" orders that provide market liquidity receive a rebate
• "Taker" orders that remove market liquidity are charged a fee
• Fees are calculated as a percentage of the order value (denominated in the settlement asset)

Contract	Maker Rebate	Taker Fee
BTCUSD Perpetual Swap	-0.025%	0.075%

Order Matching Rules: Qume operates a centralized limit order book matching engine. Order matching abides by the “first-in-first-out” principle, or “FIFO”:

• Price and time are the only criteria for filling an order
• All orders at the same price level are filled according to time priority

API Connectivity: Qume offers low-latency REST and WebSocket APIs. Use these APIs to create custom trading systems and clients. See our Developer Resources for more information.

The private REST API allows users to:

• query open positions
• place orders
• cancel orders
• query account balances
• modify leverage and margin

The public REST API provides specific market data upon request, including:

• order book data
• trade history
• price indices

Qume also offers public Websocket streams for market data and private WebSocket streams for authenticated account data. 

Performance Benchmarks: Qume's order matching engine and supporting infrastructure are optimized to provide microsecond-level execution latency. Additionally, each contract market can support up to 100,000 transactions per second. 

• Mean round-trip latency (from external API request to response, excluding network delay) for placing a limit order is 2.5 milliseconds via REST and 80 microseconds via FIX 
• 9% of requests (for time-sensitive operations) are returned in <10 milliseconds

For more detailed performance benchmarks, including comparisons with other exchanges, please email [e-mail]