A piece of code known as an application programming interface, or API, enables information sharing between two apps. An online hotel booking aggregator is a nice illustration of an API. In response to a customer's request, the aggregator site uses APIs to obtain data from several hotel companies. For instance, the customer asks for details on any rooms that fit a certain set of requirements, such as the start and end dates of their stay, the location, and the price. Using an API, which converts the request into a format that the hotel servers can comprehend, this data is transmitted to the hotel's computer systems. These systems then respond via the API with the rooms that are accessible and meet these requirements. Despite the fact that the aggregator website and the hotel system were developed using separate technologies and by different firms, the API makes it possible for information to be exchanged fast and efficiently. The hotel is the API provider in this instance. It has created the API so that other Apps can access the data. The hotel does this in order to make it simple for customers to learn about the rooms that are available. The API is used by the aggregation website. Without an API, obtaining the data it requires would either be impossible or too labor-intensive. What can be done with APIs? Instead of creating a workaround or exploiting existing functionality and data, APIs allow developers to access them. For instance, the developer can avoid having to draw or write map functionality from scratch by leveraging the Google Maps API to display the location of a store or restaurant. This helps you save a lot of time and money. Wherever there is a need for software to interface with other software, APIs are there, and since making data accessible benefits businesses, many of them are free to use. For instance, Blockchain offers free APIs that provide programmers access to wallet services, transaction data, and market information for use in their websites and applications. Exchanges for cryptocurrencies also offer APIs. Trading bots can execute transactions (in accordance with predetermined instructions) on behalf of traders by receiving market data from traders via these APIs. The term "assembly" refers to a type of trading that takes place in a controlled environment.