API stands for "Application Programming Interface". An API is a set of protocols, routines, and tools that are used to build software applications. An API defines how different software components should interact with each other. It provides a standard way for different software applications to communicate and share data with each other.

APIs can be used for a variety of purposes, such as:

1. Integrating with third-party services: APIs can be used to integrate with third-party services such as payment gateways, social media platforms, and cloud services. This allows developers to build applications that can leverage the functionality of these services.
2. Building web and mobile applications: APIs can be used to build web and mobile applications that interact with back-end services. For example, an e-commerce application may use an API to retrieve product information from a database.
3. Creating software libraries: APIs can be used to create software libraries that other developers can use in their applications. This allows developers to reuse code and reduce the amount of code they need to write.
4. Automating tasks: APIs can be used to automate tasks such as data extraction and manipulation. For example, an API may be used to extract data from a website and store it in a database.

APIs can be classified into different types, such as RESTful APIs, SOAP APIs, and GraphQL APIs. Each type has its own set of characteristics and is suited for different use cases.

API is a set of protocols, routines, and tools that define how different software components should interact with each other. APIs are used for a variety of purposes, such as integrating with third-party services, building web and mobile applications, creating software libraries, and automating tasks.

In this course we are going to use RESTful APIs