In the context of trading, an API service, or Application Programming Interface service, refers to a set of tools and protocols that enable developers to build automated trading systems. Trading APIs allow users to access and interact with trading platforms, exchanges, and financial data programmatically rather than through traditional user interfaces. This capability empowers developers to create various automated trading strategies based on predefined rules and conditions. By leveraging trading APIs, users can programmatically execute trades, retrieve market data, manage positions, and perform other trading-related tasks, enabling more efficient and systematic trading strategies.