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How to build a Stock App using RealStonks API?

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Sun Feb 27 2022

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9 min read

Saad Irfan

If you sell and buy stock often, you would need to stay up-to-date with the market trends. Instead of looking up different stock data on the internet, we can build an application for it using an API from RapidAPI Hub. Let’s take a look at it.

Stack

We need to choose a stack first to build this application. I have decided to go with the Jamstack.

I am going to use Next.js for the frontend and TailwindCSS for the styling.

If you don’t know about Next.js, it is a JavaScript framework built on top of React and provides features like server-side rendering, static site generation, etc. Tailwind is a CSS framework that provides utility classes to speed up the development process.

Choosing The API

Let’s find an API that we can use to find the stock information. Go to RapidAPI Hub and create an account if you haven’t already and then search for “stocks api” in the search section.

Loading component...

You will see different search results related to stocks API. For this piece, I am using RealStonks API.

To use this API, you need to subscribe to it first. You can do this by clicking on Subscribe to Test button.

Subscribe to Stocks API

Once you click the button, you will be redirected to another page where different available subscription packages will be shown. Let’s go with the free one for now.

After all this, you will be redirected back to the original page. Here you will have a key x-rapidapi-key. Save it. It will be used later in the application.

Building The UI

You can create a Next.js boilerplate with TailwindCSS integrated by running the following command in your terminal. So let’s do that.

sh
npx create-next-app -e with-tailwindcss stocks-app

This command is going to take a minute to set everything up. After generating the boilerplate, you will see a folder with the name stocks-app has been created. Open this folder in your preferred code editor. I will use VSCode for this project.

Project Files

When you open the project in your code editor, you will see the following directories and files in the root directory:

pages directory: Inside it, you will have files index.js, _app.js, and another directory called api. You only need to know about the index.js file that is the main entry point in your project.
public directory: This directory contains icons. You place your static files here to load later in the application.
node_modules: It’s another directory that contains all the node modules you are using in your application.
package.json: This file contains the metadata of your project.
package-lock.json: This file is responsible for tracking the exact version of every installed package.
postcss.config.js: This file contains PostCSS configurations.
tailwind.config.js: It contains TailwindCSS configurations.
readme.md: It’s a markdown file for documentation.

Before we move on to writing the code, open this file, and copy all of its content, then paste it inside the tailwind.config.js file in your project. These are some TailwindCSS configurations I have done specifically for this project. I have added some colors that you do not have by default with TailwindCSS and set some screen sizes.

Now let’s start writing the code. I am going to do it in steps so you can follow along:

→ STEP #1

Open the pages/index.js file and remove all the existing code. After this, copy-paste the following code there:

jsx
export default function Home() {
	return (
		<div className="flex flex-col items-center relative min-h-screen">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				<span className="text-secondary">Stocks</span> App
			</h2>
			<h3 className="text-lightGrey text-2xl font-raleway font-bold uppercase tracking-wide mb-12 md:text-base md:px-4 md:text-center">
				Get info of any stocks quickly
			</h3>
		</div>
	);
}

It will create two headings for you with the text “Stocks App” and “Get info of any stocks quickly”. You can change it to anything you prefer.

→ STEP #2

Now let’s create an input field and a search button. The user will be able to type the stock name in the input box and use the search button to get the stock information.

For this, copy the following code and paste it in pages/index.js:

jsx
export default function Home() {
	return (
		<div className="flex flex-col items-center relative min-h-screen">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				<span className="text-secondary">Stocks</span> App
			</h2>
			<h3 className="text-lightGrey text-2xl font-raleway font-bold uppercase tracking-wide mb-12 md:text-base md:px-4 md:text-center">
				Get info of any stocks quickly
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						type="text"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Name of stock..."
					/>
					<button className="outline-none border border-danger font-bold font-raleway ml-4 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-black md:ml-0 md:mt-4">
						Search
					</button>
				</form>
			</div>
		</div>
	);
}

This code is going to create an input field and button. I have also styled them a little bit using TailwindCSS.

→ STEP #3

Let’s create some states to store the stock name and the stock information that we will receive from the API. For this, copy-paste the following code in pages/index.js:

jsx
import {useState} from 'react';
export default function Home() {
	const [stock, setStock] = useState('');
	const [res, setRes] = useState(null);
	return (
		<div className="flex flex-col items-center relative min-h-screen">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				<span className="text-secondary">Stocks</span> App
			</h2>
			<h3 className="text-lightGrey text-2xl font-raleway font-bold uppercase tracking-wide mb-12 md:text-base md:px-4 md:text-center">
				Get info of any stocks quickly
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						type="text"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Name of stock..."
						onChange={e => setStock(e.target.value)}
					/>
					<button className="outline-none border border-danger font-bold font-raleway ml-4 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-black md:ml-0 md:mt-4">
						Search
					</button>
				</form>
			</div>
		</div>
	);
}

You can see that I have added an onChange event handler to set the state value as soon as the user types something in the input box.

→ STEP #4

Let’s integrate the API now. For this, first, create a .env.local file and paste the following in it:

sh
NEXT_PUBLIC_RAPIDAPI_KEY=YOUR-RAPIDAPI-KEY

You need to replace YOUR-RAPIDAPI-KEY here with the API key you got when you subscribed to the RealStonks API. It is the value of x-rapidapi-key that you saved earlier.

Now download and add axios in your project. For this, run the following command in the terminal:

sh
npm install axios

Now import axios at the top of the pages/index.js.

js
import axios from 'axios';

→ STEP #5

RapidAPI Hub provides you with code snippets in different languages for integrating the API. I am going to use the (JavaScript) Axios one.

Fetching data using (JavaScript) Axios

Now create a file with the name info.js inside the pages/api directory. It is going to create a REST API endpoint for you. The endpoint point will look like this:

sh
http://localhost:3000/api/info

Now copy the following code in this file:

js
import axios from 'axios';
export default async function handler(req, res) {
	if (req.method === 'GET') {
		const options = {
			method: 'GET',
			url: `https://realstonks.p.rapidapi.com/${req.query.stock}`,
			headers: {
				'x-rapidapi-host': 'realstonks.p.rapidapi.com',
				'x-rapidapi-key': process.env.NEXT_PUBLIC_RAPIDAPI_KEY
			}
		};
		axios
			.request(options)
			.then(function (response) {
				res.status(200).json(response.data);
			})
			.catch(function (error) {
				res.status(404).json(error);
				console.error(error);
			});
	} else {
		res.status(400);
	}
}

This code makes an API call to the RealStonks API on the server and returns the results to the user. It executes when the user makes an API call to the info endpoint I mentioned above.

Once you are done, copy the following code in the pages/index.js file:

jsx
import {useState} from 'react';
import axios from 'axios';
export default function Home() {
	const [stock, setStock] = useState('');
	const [btnText, setBtnText] = useState('Search');
	const [res, setRes] = useState(null);
	const [error, setError] = useState(null);
	/**
	 *
	 *
	 * Fetch stock information from the API
	 */
	const fetchStockInformation = async e => {
		e.preventDefault();
		try {
			setRes(null);
			setError(null);
			setBtnText('Loading...');
			const res = await axios.get(`/api/info`, {
				params: {stock}
			});
			if (res.status === 404) {
				throw err;
			}
			setRes(res.data);
		} catch (err) {
			setError(err);
		}
		setBtnText('Search');
	};
	return (
		<div className="flex flex-col items-center relative min-h-screen">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				<span className="text-secondary">Stocks</span> App
			</h2>
			<h3 className="text-lightGrey text-2xl font-raleway font-bold uppercase tracking-wide mb-12 md:text-base md:px-4 md:text-center">
				Get info of any stocks quickly
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						type="text"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Name of stock..."
						onChange={e => setStock(e.target.value)}
					/>
					<button
						className="outline-none border border-danger font-bold font-raleway ml-4 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-black md:ml-0 md:mt-4"
						onClick={fetchStockInformation}
					>
						{btnText}
					</button>
				</form>
				{res && (
					<div className="flex flex-col text-raleway mt-12 w-3/6 h-4/5 md:w-5/6 md:h-full md:mb-12">
						<table className="text-primary border-danger border md:text-sm md:mx-2">
							<tbody>
								<tr>
									<td className="border-danger border px-4 py-4">
										Price
									</td>
									<td className="border-danger border px-4 py-4">
										USD {res.price}
									</td>
								</tr>
								<tr>
									<td className="border-danger border px-4 py-4">
										Change Percentage
									</td>
									<td className="border-danger border px-4 py-4">
										{res.change_percentage}
									</td>
								</tr>
								<tr>
									<td className="border-danger border px-4 py-4">
										Change Point
									</td>
									<td className="border-danger border px-4 py-4">
										{res.change_point}
									</td>
								</tr>
								<tr>
									<td className="border-danger border px-4 py-4">
										Total Vol
									</td>
									<td className="border-danger border px-4 py-4">
										{res.total_vol}
									</td>
								</tr>
							</tbody>
						</table>
					</div>
				)}
				{error && (
					<div className="flex flex-col mt-16 w-3/6 h-4/5 md:flex-col md:w-4/6 md:h-full md:mb-12 md:w-4/5">
						<p className="mb-12 border border-secondary text-primary font-raleway px-4 py-8 tracking-wide leading-8">
							{error.toString()}
						</p>
					</div>
				)}
			</div>
			<div className="flex flex-col mt-10 justify-end h-36 md:h-24">
				<p className="block mb-10 text-center text-secondary text-xs">
					Made by RapidAPI DevRel Team -{' '}
					<a
						className="hover:text-primary"
						href="https://github.com/RapidAPI/DevRel-Examples-External"
					>
						See more examples like this
					</a>
				</p>
			</div>
		</div>
	);
}

You can see that I have created a function, fetchStockInformation, to request the API. I have also created a UI that is conditionally rendering on the screen based on the res state variable value.

Wrap Up

That’s it. We have successfully built a Stocks App using RealStonks API. You can find the source code of this web app here.

In the end, it will look something like this:

Stocks App built with Next.js and RealStonks API

# RapidAPI # stock-app

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