What is the main purpose of an API and how is it used in software development?

API (Application Programming Interface) is a set of rules and tools that allows different software systems to interact with each other. The main purpose of an API is to provide a standardized way to exchange data and invoke functions between components or applications.

In software development, APIs are used for:

• Integration with external services (e.g., payment systems, maps, social networks).
• Separation of functionality between client and server parts.
• Automation and extension of application capabilities.

Example: a mobile app calls the server API to get user data by sending an HTTP request and receiving a JSON response.