Design Stock Trading System

Requirements Definition

Functional Requirements:

• Allow users to place buy and sell orders for stocks.
• Support order cancellation before execution.
• Match buy and sell orders according to price and time priority.
• Provide real-time market data (current prices, order book snapshots).
• Allow users to view their active orders and trade history.

Non-Functional Requirements:

• System should be highly available during trading hours.
• Low latency for order placement and matching (sub-second response time).
• Ensure data consistency and integrity, especially for trades and balances.
• Secure APIs for user authentication and authorization.
• Scalability to handle a moderate number of concurrent users and orders (e.g., thousands per second).

Out of Scope:

• Advanced order types (e.g., stop-loss, iceberg) are not required for the initial version.
• No support for margin trading or derivatives in the initial design.
• No direct integration with external clearing or settlement systems at this stage.