{"id":18532,"date":"2020-06-25T15:14:22","date_gmt":"2020-06-25T22:14:22","guid":{"rendered":"https:\/\/careerkarma.com\/blog\/?p=18532"},"modified":"2023-12-01T03:34:36","modified_gmt":"2023-12-01T11:34:36","slug":"restful-api","status":"publish","type":"post","link":"https:\/\/careerkarma.com\/blog\/restful-api\/","title":{"rendered":"What is a RESTful API?"},"content":{"rendered":"\n

At some point in your career as a developer, you\u2019ve likely encountered RESTful APIs. But, do you know what they are? How do they work?
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In this guide, we discuss the essentials of REST APIs, covering everything you need to know to query a REST API.<\/p>\n\n\n\n

What is a RESTful API?<\/h2>\n\n\n\n

RESTful APIs allow you to retrieve data. For example, you can use a REST API to retrieve data about your favorite movies from a movie API, or your fitness data from the Fitbit API.
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API stands for \u201cApplication Programming Interface.\u201d It is a program that allows websites and servers to talk to each other. An API is hosted on a server with its own database; websites and programs can retrieve data from the API.
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REST, which stands for \u201cREpresentational State Transfer,\u201d is a set of guidelines determining how a web API should be structured.<\/p>\n\n\n\n

REST Request Example<\/h2>\n\n\n\n

To work with an API using the REST architectural style, you need to make a request. The data that you receive after you make a request is called the response.
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Let\u2019s start by discussing endpoints. When you\u2019re making a request, you need to query an endpoint. This is the URL from which you want to get data. 
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Suppose you want to retrieve data from the Hacker News API. This API allows us to retrieve data on posts from the Y Combinator Hacker News platform.
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To make your request, you need to read through the API documentation. In this case, the Hacker News API says that we can use the following URL to retrieve a story:<\/p>\n\n\n\nhttps:\/\/hacker-news.firebaseio.com\/v0\/item\/:postid.json?print=pretty\n\n\n\n

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In this example, :postid is the post that we want to retrieve. Generally speaking, when you see colons in API documentation, you should insert a variable. In this case, suppose we want to get the post with the ID 23460066. We could do so using this URL:<\/p>\n\n\n\nhttps:\/\/hacker-news.firebaseio.com\/v0\/item\/23460066.json?print=pretty\n\n\n\n

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Now that we have a REST request ready, we can make our request to the API.<\/p>\n\n\n\n

Making a REST Request<\/h2>\n\n\n\n

Most programming languages have their own modules to allow web requests. Python offers the Python requests package. JavaScript offers the Fetch API and isomorphic-fetch. For this tutorial, we\u2019re going to use a command line program called cURL. This allows you to make web requests from your command line.
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To make a request, all we have to do is use the curl command, followed by the REST URL that we want to query. In the example of the Hacker News API above, we\u2019d use the following command:<\/p>\n\n\n\n

curl https:\/\/hacker-news.firebaseio.com\/v0\/item\/23460066.json?print=pretty<\/pre><\/div>\n\n\n\n
Our code returns:
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As you can see, the API has returned the data for the post with the ID 23460066. We can see the post\u2019s author, comment \u201ckids,\u201d title, and more. If we want to get another post, all we have to do is change the post ID.
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The data returned by a request is usually structured in the JSON format. JSON stands for JavaScript Notation, and is a standard way of expressing data.
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In JSON data, keys are stored on the left-hand side of a colon. The key is the label that is assigned to a value. Values are stored on the right-hand side of a colon. Here\u2019s an example key-value pair from the above response:<\/p>\n\n\n\n
\"by\": \"arkadiyt\"<\/pre><\/div>\n\n\n\n
The key in this case is \u201cby\u201d and the value is \u201carkadiyt\u201d. These values are separated with a colon.<\/p>\n\n\n\n
How do REST Requests Work?<\/h2>\n\n\n\n
There are four parts to a REST request:
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