An API provides a clear set of rules that allow one system to request information or actions from another. These rules define how requests must be formatted, what data is available, and how the response will be delivered. This standardization makes it possible for different applications, platforms, and services to connect reliably.
APIs are used in almost every part of modern software. They power data transfers, automate tasks, integrate services, and allow applications to interact with external systems. Because APIs follow consistent structures, developers can build features faster and maintain cleaner architectures.
There are several types of APIs, including REST, WebSocket, and GraphQL. Each type supports different use cases. REST APIs handle structured data requests, WebSockets support continuous real-time streaming, and GraphQL allows flexible queries for specific fields. APIs may also use different formats such as JSON or XML for delivering data.
Security, authentication, rate limits, and permission controls are critical parts of API design. These features ensure that only authorized users can access the system and that the API can operate reliably at scale.
APIs make modern finance, trading, and automation possible. They let tools exchange real-time data, power automated trading systems, feed dashboards, and connect platforms that would otherwise be siloed.
REST APIs work through individual request–response actions and are ideal for standard data retrieval. WebSocket APIs maintain an open connection, allowing continuous real-time updates, which is useful for live prices and streaming data.
APIs use authentication methods such as API keys, OAuth, and token-based systems. They also implement rate limits, encryption, and permission controls to protect data and prevent unauthorized access.
Key factors include latency, response size, server capacity, caching, data source speed, and how well the API handles high traffic. Monitoring these metrics helps maintain stable performance.
When a trading app displays live stock prices, it isn’t calculating them on its own. It’s calling a market data API every second to fetch the latest numbers. The user only sees the final result, but the API is doing all the work behind the scenes.
FinFeedAPI provides APIs for market data—including SEC filings, stock data, currencies, and even prediction markets. Developers use these APIs to automate research, feed dashboards, power trading bots, or build AI agents that react instantly to new financial data. With clean, consistent endpoints, FinFeedAPI makes it easy to work with real-time and historical market information.
