APIs

6.1. APIs#

6.1.1. What Is an API?#

  • API stands for Application Programming Interface.

  • An API is a way to programmatically interact with a applications or other software.

  • A document that describes how an API behaves is called the API specification.

  • Actual software that meets the specification is said to implement or expose an API.

  • APIs are written by software developers so that other developers can extend or interact with their software.

APIs are used by almost every piece of software we use on a daily basis. For example an graphical application on your computer uses APIs provided by the operating system to create windows and draw to the screen.

6.1.2. What Is a Web API?#

  • A web API is an API that works over the web using the HTTP protocol.

  • Web APIS allow communication between clients such as web browsers, desktop and mobile apps with a server.

Web APIs are now a staple of software. You likely use apps on your computer or mobile phone that rely on web APIs.

For example

  • Social media apps like Facebook, Twitter, Reddit, Instagram, Tiktok etc download user posts and upload submissions using a web API

  • Communication apps like Slack or Discord use a web API to synchronise messages

  • Weather apps use a Web API to retrieve the current weather and latest weather forecast

6.1.3. How Do Web APIs Work?#

  • Web APIs use HTTP requests and responses to exchange data with an API server.

  • However, the data exchanged is not HTML

  • The data is usually plaintext but formatted as JSON or XML

6.1.4. What is JSON?#

  • JSON stands for JavaScript Object Notation.

  • It’s a lightweight, human-readable format for storing and exchanging data.

Example

The example below shows a JSON “Object”, which is like a dictionary, of a student. You can also find various other data types that are supported in JSON like strings, arrays and numbers.

{
"name": "Alex",
"age": 17,
"skills": ["Python", "HTML"],
"address": {
    "city": "Sydney",
    "postcode": "2000"
}
}