What is API? Can we build them.what are the languages used for building APIs

Answer 1

https://www.sololearn.com/discuss/1027271/?ref=app
Check this lesson:
https://www.sololearn.com/learn/HTML/2198/

Answer 2

An API can be built in almost any language, and there are even frameworks and libraries that allow you to build your application and implement an API. The APIs are mainly a way of interacting with your application (through the execution of services or the obtaining of data that you store in your application).

In the following links there is more detailed information about what an API is, how to build one, and other data that is important to consider:

* http://www.andrewhavens.com/posts/20/beginners-guide-to-creating-a-rest-api/
* https://medium.com/the-era-of-apis/20-tutorials-on-how-to-create-your-own-api-sorted-by-programming-language-9ad2fa5fc429