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[MUSIC]

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>> Hey, I'm Treasure, a JavaScript
developer and teacher here at Treehouse.

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In this course, we'll be using
the popular Node.js platform and

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Express framework to build a type of
web application called a REST API.

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To define a REST API, we first need to
talk about a traditional web application.

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Traditional web applications handle
both serverside and clientside concerns.

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Say you build a web application to keep
a record of your favorite recipes.

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To view a certain recipe,
you'd click on that recipe's URL, and

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your browser would request
that recipe from a server.

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A traditional server side application
would respond to that request by finding

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the RESP data in a database, assembling
that data into HTML templates and

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sending that HTML back to
the browser to be displayed.

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Seems reasonable but what if you wanted to
use that same RESP information to build

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a mobile app or
an entirely different application?

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That's where REST API comes in, when you
request a specific recipe in a RESTful

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application, the application
responds only with the recipe data,

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typically in the form of JSON.

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Sending JSON data rather than HTML means
the back end only has to be built once.

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While any number of front end applications
can consume and display the data.

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When designing an application this way,

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you can manipulate the same
data in endless ways.

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If I have a REST API for recipes, for
example, I could create a recipe website.

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But I could also use the same data
to create a meal planning app,

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a calorie tracking app,
a virtual cookbook, and on, and on.

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As another good example,
think about the Twitter app on your phone.

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The phone app makes a request
to Twitter RESP API,

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to get the tweets before you see them.

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The JSON from Twitter's API is then
formatted and displayed on your phone.

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But the Twitter API allows the same
tweet data to be accessed and

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used by a web browser,
a smart TV, or a home IoT device.

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REST APIs can provide data and content for
rich web applications, mobile apps,

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and other serverside applications,

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even those applications written
in other programming languages.

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Basically, a REST API lets
you retrieve data and

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present that data in any way you want,
providing amazing flexibility.

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I'll review some key concepts in
this course, but to be successful,

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you should be familiar
with the basics of node,

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building a serverside application
with Express, and Express middleware.

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You should also be familiar
with asynchronous JavaScript,

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specifically using Callbacks,
Promises, and Async Await.

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See the teacher's notes below for
the prerequisite courses.

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In this course, we'll use Node and

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Express to build out a simple API that
provides data about famous quotes.

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When we're finished, users will be able
to request famous quotes from our API,

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as well as add new quotes, edit and
delete existing quotes, and

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request a random quote.

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As we build this project,
you'll learn more about how API's work and

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specifically, how to
build one with Express.

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Let's dig a bit more into
the structure of an API.