An external API call refers to a request made by one application to another through an Application Programming Interface (API). In cryptocurrency, these calls are used to interact with various blockchain networks, wallets, and data providers.When an application needs real-time data, such as current prices, trading volumes, or historical transaction information, it sends an external API call to a specific source. This source could be a cryptocurrency exchange, a blockchain explorer, or a price aggregator.These API calls are essential for enabling functionalities like trading automation, portfolio management, and price tracking. For instance, a trading bot may use an API call to place buy or sell orders on an exchange based on market conditions.Security is a crucial consideration when making external API calls. Proper authentication and data validation help prevent unauthorized access and ensure the integrity of transactions and information exchanged between applications. Overall, external API calls enhance the interconnectivity and functionality of various tools and services within the cryptocurrency ecosystem.