An application programming interface (API) establishes an online connection between a data provider and an end-user. For financial markets, APIs interface trading algorithms or models and an exchange's and/or broker's platform. An API is essential to implementing an automated trading strategy.
An application programming interface, or API, is a set of programming code that queries data, parses responses, and sends instructions between one software platform and another. APIs are used extensively in providing data services across a range of fields and contexts.