PubNub vs Pusher creating a realtime messaging app in React

Real-time data is one of the core pillars for modern applications these days. Having a system that is capable of sending bi-directional information allows us to stay up to date with a variety of information. Such examples can include messaging applications, data analytics for dashboards used for financial data, heads up displays (HUD's) used in augmented and virtual applications. Like a fighter pilot flying an aircraft or a casual consumer using an Apple Vision Pro headset. There are endless use cases for this technology.

When talking about general IM applications, having the ability to speak to someone in real-time opens up the door to so many unique possibilities. Our world has become ever more connected as a result of these newfound capabilities. In todays article we will learn all about messaging as we build a real-time messaging application. The application will be able to connect to two different real-time application platforms which are Pusher and PubNub.

Our application will be pretty similar to a basic, barebones version of the WhatsApp and Telegram applications. It will be possible to open more than one web browser or browser tab and this will give us the power to sign in with multiple users. This way we can test out group chat between more than one user just like you would if it was a real chat application.

Below you can see what our main dashboard will look like, as you can see there are buttons to navigate to both versions of our messaging app:

And here you can see what the PubNub version of our app looks like in this screenshot. It is depicted by a blue header:

The Pusher version has a green header and with this you will be able to visually tell the difference between the two of them:

Alright with our quick introduction completed we can now take a much more thorough look as we see how they contrast with each other. The codebase for the messaging application can be found on my GitHub here: https://github.com/andrewbaisden/realtime-chat-app.

Prerequisites

Before we begin, take a look at these prerequisites and make sure that you have everything set up before we get started.

• Node and npm installed.
• An IDE installed like Visual Studio Code
• An account on PubNub
• An account on Pusher

PubNub vs Pusher

Both platforms share a lot in common but there are some noticeable differences which makes them easy to distinguish. One of the main ones is the fact that their architecture is not the same.

Architectural Differences

In the case of PubNub it is a cloud platform which can take care of data and message streaming. There is very low latency as good service availability as it is available worldwide. The scaling and infrastructure is well handled by the platform so developers are free to work on what matters which is the projects.

Now with Pusher they offer different deployment options which are self-hosted and cloud hosted. When using the self-hosted, Pusher is capable of running on your own custom hardware or software and this gives you so much freedom. When it comes to the cloud-hosted solution, you can expect a similar service to PubNub's.

API and SDK Comparison

When we compare there features we can see that they both offer SDKs and libraries which are supported by numerous programming languages. These include JavaScript, Python, Java, Swift, Ruby and many others. Channels are available on both platforms and this lets us to publishing and subscribing for various data streams. Presence is another option and with this we can see online and offline status for all users in real-time on the different channels we setup. In regards to the message history its a similar story and the same applies to push notifications.

Another great aspect is the fact that they are feature rich and the documentation is very through making it very easy to learn and get up to speed on the different quirks on offer. You can find their respective documentation below:

PubNub Documentation: PubNub
Pusher Documentation: Pusher

Implementing a Real-time Messaging App with React

Time to work on our application! First ensure that you have an account on PubNub and Pusher first we shall quickly go through the process of creating an account on both platforms now so follow along if you have not created accounts yet.

Creating an account on PubNub

Starting with PubNub got to the homepage of the website and click on the button at the top on the right to try for free as shown below.

You should now see the registration page so go ahead and use the form to create your account.

Ok now with your account created access to the dashboard should be possible. Use the menu to go to Keysets section and then find your app and its keyset. This is also the part where you should create an app if there is not one there already.

Your API keys should be visible now so ensure that the presence and persistence options are on because we need this to track users and the data.

Creating an account on Pusher

Right so we are done with our PubNub account for now lets work on our Pusher one. Like before go to the website and click the sign up button in the top right hand corner of the page.

Now on the following screen, use the form to create an account like you see here.

A channel must be created so on the dashboard page select the manage button to do so.

On the next page which should be the channel screen, create an app by using the create app button as shown in this screenshot.

Now we can move onto the form and as you can see in this example the configuration should be tailor made for your use case.

So once that stage has been completed the channel page should be displayed like it is here.

Click on the App Keys which is in the sidebar menu and then you will get access to the API keys that you need later.

Great so the account setup phase is now done, in the next section we will make a start on the code for our app. The first step will be making the project architecture with the folders etc... I went ahead and created a copy and paste script for the command line so we don't have to write out all of the commands manually. Start by creating a project on your computer called realtime-chat-app and then go to the location using the command line.

Setting up the React application

Use Next.js to create a project and then use the shell script to setup the project.

We begin by running this command to create a Next.js project:

npx create-next-app client

Now on the configuration screen its important to choose Tailwind CSS and the App Router because we need those options in this project.

Right here is the shell script for creating the files and folders and installing the dependencies just run it inside of the same folder, it will automatically cd into the client folder. If you are already in the client folder then you can omit the first line in the script.

cd client
npm install @pubnub/react-chat-components axios pubnub pubnub-react pusher pusher-js
touch .env.local
cd src/app
mkdir components pubnub pusher
touch components/ChatInterface.js components/ChatMessage.js components/ChatPubNub.js components/ChatPusher.js components/DashboardButton.js components/Header.js components/UserLogin.js pubnub/page.js pusher/page.js
cd ../../..
mkdir server
cd server
npm init -y
npm install express cors pusher dotenv
touch index.js .env
cd ..

There is a lot going on here so lets see what this script is doing:

• Installing the dependencies for our project which includes the packages and the PubNub and Pusher packages
• Creating environment variable files for our API keys
• Making the files, folders and components for our entire app
• Setting up a backend server that Pusher will need for API access
• Building the server files for routing and logic purposes

Have a look at this screen grab this is how our project should look in your IDE:

The hard work is done that build script did most of the work we just have to add the code to the files.

Right our first file is the globals.css file so clear all the code in that file and replace it with what is shown here:

@tailwind base;
@tailwind components;
@tailwind utilities;

body {
  background-color: rgb(15 23 42);
}

Code cleanup has been done in this file and now we have a background colour for our application.

Onto the layout.css file. Continuing from what we just did replace all the code with this new code:

import { Ubuntu } from 'next/font/google';
import './globals.css';

const ubuntu = Ubuntu({
  subsets: ['latin'],
  weight: ['300', '400', '500', '700'],
});

export const metadata = {
  title: 'Realtime Chat App',
  description: 'Generated by create next app',
};

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body className={ubuntu.className}>{children}</body>
    </html>
  );
}

Ubuntu is now the default font in our application.

All thats left in this section is to replace all of the code in our next.config.mjs file with this code:

/** @type {import('next').NextConfig} */
const nextConfig = {
  images: {
    remotePatterns: [
      {
        hostname: 'res.cloudinary.com',
      },
    ],
  },
};

export default nextConfig;

Cloudinary was added as an image host so now we can use it throughout our app.

And with that the project setup phase is done so in the next section we will work on the main files for our codebase. First we will do PubNub and then we will do Pusher.

Integrating PubNub

The initilisation and configuration part will be the first one to tackle. You must sign into your PubNub account, and find the application you made at the start. Locate your Keysets as well as the Publish and Subscribe Keys. Now put them inside of the .env.local file in the project.

Here is an example of where they should be put:

NEXT_PUBLIC_PUBNUB_PUBLISH_KEY=your-publish-key
NEXT_PUBLIC_PUBNUB_SUBSCRIBE_KEY=your-subscribe-key

Time to add some code to our components/ChatPubNub.js file, and this is the file where we can find the main code for subscribing to channels, handling the presence and publishing our message.

Put the code you see here into the components/ChatPubNub.js file:

import { useState, useEffect, useRef } from 'react';
import PubNub from 'pubnub';
import ChatInterface from './ChatInterface';

export default function ChatPubNub({ activeUser }) {
  const [chats, setChats] = useState([]);
  const [count, setCount] = useState(1);
  const bottomRef = useRef(null);

  let pubnub;
  const channelName = 'presence-chatroom';

  useEffect(() => {
    pubnub = new PubNub({
      publishKey: process.env.NEXT_PUBLIC_PUBNUB_PUBLISH_KEY,
      subscribeKey: process.env.NEXT_PUBLIC_PUBNUB_SUBSCRIBE_KEY,
      uuid: activeUser,
    });

    pubnub.addListener({
      message: (messageEvent) => {
        const chat = messageEvent.message;
        setChats((prevChats) => [...prevChats, chat]);
      },
    });

    const presenceChannelName = `${channelName}-pnpres`;

    pubnub.subscribe({
      channels: [channelName],
      withPresence: true,
      presenceChannels: [presenceChannelName],
    });

    const scrollToBottom = () => {
      bottomRef.current?.scrollIntoView({ behavior: 'smooth' });
    };

    scrollToBottom();

    return () => {
      pubnub.unsubscribeAll();
    };
  }, [chats, activeUser, count]);

  const handleKeyUp = (evt) => {
    const value = evt.target.value;
    if (evt.keyCode === 13 && !evt.shiftKey) {
      const chat = { user: activeUser, message: value, timestamp: +new Date() };
      evt.target.value = '';
      pubnub.publish({
        channel: channelName,
        message: chat,
      });
    }
  };

  return activeUser ? (
    <>
      <ChatInterface
        activeUser={activeUser}
        count={count}
        chats={chats}
        handleKeyUp={handleKeyUp}
        bottomRef={bottomRef}
      />
    </>
  ) : null;
}

Here is a quick explanation of what our code does in this file. We can do subscriptions to channels, publish messages to different channels as well as handle the overall presence information. With these capabilities our app will function a lot like a group chat and with presence switched on we can see how many users are online in real-time.

We can work on our next file now which is the components/ChatInterface.js so add this code to it:

import ChatMessage from './ChatMessage';

export default function ChatInterface({
  activeUser,
  count,
  chats,
  handleKeyUp,
  bottomRef,
}) {
  return (
    <div className="flex">
      <aside className="w-64 min-w-64 bg-slate-800 p-2">
        <h1 className="text-lg text-white">Chats</h1>
        <div className="flex justify-between mt-2">
          <div className="flex">
            <div className="rounded-full bg-slate-100 h-10 w-10 mr-2"></div>
            <div className="text-sm">
              <p className="text-white">John</p>
              <p className="text-slate-400">Hello world</p>
            </div>
          </div>
          <div className="text-sm text-slate-400">Friday</div>
        </div>
      </aside>
      <section className="grow">
        <div className="bg-zinc-800 p-2">
          <div className="flex">
            <div className="rounded-full bg-slate-100 h-10 w-10 mr-2"></div>
            <div>
              <h1 className="text-2xl text-white">{activeUser}</h1>
              <span className="text-gray-300">users online: {count}</span>
            </div>
          </div>
        </div>
        <div className="bg-zinc-900 p-2 overflow-y-auto h-80 max-h-80 text-white">
          {chats.map((chat, index) => {
            const previous = Math.max(0, index - 1);
            const previousChat = chats[previous];
            const position = chat.user === activeUser ? 'right' : 'left';
            const isFirst = previous === index;
            const inSequence = chat.user === previousChat.user;
            const hasDelay =
              Math.ceil(
                (chat.timestamp - previousChat.timestamp) / (1000 * 60)
              ) > 1;
            return (
              <div key={index}>
                {(isFirst || !inSequence || hasDelay) && (
                  <div>
                    <span>{chat.user || 'Anonymous'}</span>
                  </div>
                )}

                <ChatMessage message={chat.message} position={position} />
              </div>
            );
          })}
          <div ref={bottomRef} />{' '}
        </div>
        <div className="w-full bg-zinc-800 p-2">
          <textarea
            onKeyUp={handleKeyUp}
            placeholder="Enter a message"
            className="w-full block rounded mt-2 mb-2 p-2 text-white bg-zinc-600"
          ></textarea>
        </div>
      </section>
    </div>
  );
}

Our component displays the UI for our messaging chat interface. There is a section for messaging, sending messages and a sidebar, which could hold users when they are in the group.

The next component is for the components/ChatMessage.js file and this has our chat message interface.

Add this code to the file:

export default function ChatMessage({ message }) {
  return (
    <div>
      <div className="mt-4 mb-4">
        <span className="bg-zinc-600 p-2 rounded">{message}</span>
      </div>
    </div>
  );
}

Chat bubbles should become possible thanks to this component whenever we use the chat to send messages to users.

Dashboard buttons is what we require next so add this code to our components/DashboardButton.js file:

import Link from 'next/link';
import Image from 'next/image';

export default function DashboardButton({ url, img, alt }) {
  return (
    <>
      <Link href={url}>
        <div className="rounded mr-4 bg-slate-50 hover:bg-slate-200 h-96 w-96 text-center flex items-center justify-center drop-shadow-lg uppercase">
          <Image src={img} height={200} width={200} alt={alt} />
        </div>
      </Link>
    </>
  );
}

We can now easily navigate between the PubNub and Pusher versions of our real-time messaging chat app using these reusable buttons.

Ok the navigation component is next and this is for our main header. Put this code in our file at components/Header.js:

import Link from 'next/link';

export default function Header() {
  return (
    <>
      <nav className="bg-white flex justify-around p-8 mb-4 font-bold">
        <Link href={'/'}>Dashboard</Link>
        <Link href={'/pusher'}>Pusher Chat App</Link>
        <Link href={'/pubnub'}>PubNub Chat App</Link>
      </nav>
    </>
  );
}

All our page routes are easily able to be navigated using this header component which has page links.

The login screen is next and this is the code our file at components/UserLogin.js desires:

import { useState } from 'react';
import ChatPubNub from '../components/ChatPubNub';
import ChatPusher from '../components/ChatPusher';

export default function UserLogin({ bgColor, appName }) {
  const [user, setUser] = useState(null);

  const handleKeyUp = (evt) => {
    if (evt.keyCode === 13) {
      const newUser = evt.target.value;
      setUser(newUser);
    }
  };
  return (
    <>
      <main>
        <div>
          <section>
            <div className={`p-4 ${bgColor} text-slate-100`}>
              <span>
                {user ? (
                  <span className="flex justify-between text-white">
                    <span>
                      {user} <span>is online</span>
                    </span>
                    <span>{appName}</span>
                  </span>
                ) : (
                  <span className="text-2xl text-white">
                    What is your name?
                  </span>
                )}
              </span>
              {!user && (
                <input
                  type="text"
                  onKeyUp={handleKeyUp}
                  autoComplete="off"
                  className="w-full block rounded mt-2 mb-2 p-2 text-black"
                />
              )}
            </div>
          </section>
          {appName === 'PubNub Chat' ? (
            <section>{user && <ChatPubNub activeUser={user} />}</section>
          ) : (
            <section>{user && <ChatPusher activeUser={user} />}</section>
          )}
        </div>
      </main>
    </>
  );
}

Its a pretty straightforward login screen component whereby a user can choose a name and then they get redirected to the messaging app. There is logic to check which app a user is using and it automatically sends the user to the right chat interface for that version of the app.

Lets do the pubnub/page.js route file now and add this code to it:

'use client';
import Header from '../components/Header';
import UserLogin from '../components/UserLogin';

export default function PubNub() {
  return (
    <div>
      <Header />
      <UserLogin bgColor={'bg-sky-800'} appName={'PubNub Chat'} />
    </div>
  );
}

We can find the main page route for the PubNub version messaging app.

Lastly we must add code to our page.js file in the root folder to complete our application so like before just replace the code with what we have written here:

'use client';
import DashboardButton from './components/DashboardButton';

export default function Home() {
  return (
    <>
      <div className="h-screen flex justify-center items-center">
        <div className="text-center">
          <h1 className="mb-4 text-white text-4xl">Choose a messaging app</h1>
          <div className="grid gap-2 lg:grid-cols-2 md:grid-cols-1 sm:grid-cols-1">
            <DashboardButton
              url={'/pusher'}
              img={
                'https://res.cloudinary.com/d74fh3kw/image/upload/v1715187329/pusher-logo_u0gljx.svg'
              }
              alt="Pusher Logo"
            />
            <DashboardButton
              url={'/pubnub'}
              img={
                'https://res.cloudinary.com/d74fh3kw/image/upload/v1715189173/pubnub-logo-vector_olhbio.png'
              }
              alt="PubNub Logo"
            />
          </div>
        </div>
      </div>
    </>
  );
}

Our main dashboard link can be found here which has the buttons for our PubNub and Pusher version of our application.

The PubNub messaging part of our application should be good to go now! Just cd into the client folder if you have not done so already and start the application with the usual Next.js run command:

npm run dev

Its worth mentioning that the Pusher part of our application is not going to work yet as we must complete the integrations in the upcoming section. To use the PubNub app go to the login screen, enter a name and hit the enter button and then you will see the messenger chat application screen. You can see your online status and the sidebar has a hard-coded user which is just an example.

To make the application more interactive open more browser tabs or browser windows and sign in with more users. Having a real-time group chat is now possible just like any other messaging app you are familiar with.

In the next section we shall get Pusher up and working.

Integrating Pusher

This section will take less time because we get to reuse a lot of the components we used in the earlier sections. The difference this time around is that Pusher will need to connect to our backend server to work.

Like before we are going to start with the configuration files for our .env.local and .env files in the server and client folders. We need to add the same secrets to the files. Find your application on the Pusher platform and then find the App keys.

The App keys must be added to the env files with the right variables. Take a note of this key difference. Our client .env.local env file must have NEXT_PUBLIC at the start, and the .env file in the server folder does not require it and you can see that in the examples below.

Here is our .env.local file which is in the client folder:

NEXT_PUBLIC_PUBNUB_PUBLISH_KEY=your-publish-key
NEXT_PUBLIC_PUBNUB_SUBSCRIBE_KEY=your-subscribe-key
NEXT_PUBLIC_PUSHER_APP_ID=your-app-id
NEXT_PUBLIC_PUSHER_APP_KEY=your-app-key
NEXT_PUBLIC_PUSHER_APP_SECRET=your-app-secret
NEXT_PUBLIC_PUSHER_APP_CLUSTER=your-cluster

And this is the .env file which can be found in the server folder:

PUSHER_APP_ID=your-app-id
PUSHER_APP_KEY=your-app-key
PUSHER_APP_SECRET=your-app-secret
PUSHER_APP_CLUSTER=your-cluster

Time to work on the frontend so you know the drill add this code to the components/ChatPusher.js file:

import { useState, useEffect, useRef } from 'react';
import axios from 'axios';
import Pusher from 'pusher-js';
import ChatInterface from './ChatInterface';

export default function ChatPusher({ activeUser }) {
  const [chats, setChats] = useState([]);
  const [count, setCount] = useState(0);
  const bottomRef = useRef(null);

  let channel;
  let pusher;

  useEffect(() => {
    pusher = new Pusher(process.env.NEXT_PUBLIC_PUSHER_APP_KEY, {
      cluster: process.env.NEXT_PUBLIC_PUSHER_APP_CLUSTER,
      useTLS: true,
      channelAuthorization: {
        endpoint: 'http://localhost:8000/auth',
      },
    });

    channel = pusher.subscribe('presence-chatroom');
    channel.bind('new-message', ({ chat = null }) => {
      if (chat) {
        setChats((prevChats) => [...prevChats, chat]);
      }
    });

    channel.bind('pusher:subscription_succeeded', () => {
      updateMemberCount(channel);
    });

    channel.bind('pusher:member_added', () => {
      updateMemberCount(channel);
    });
    channel.bind('pusher:member_removed', () => {
      updateMemberCount(channel);
    });

    const scrollToBottom = () => {
      bottomRef.current?.scrollIntoView({ behavior: 'smooth' });
    };

    scrollToBottom();

    return () => {
      pusher.disconnect();
    };
  }, [chats]);

  const updateMemberCount = (presenceChannel) => {
    const memberCount = Object.keys(presenceChannel.members.members).length;
    console.log('Count people online', memberCount);
    setCount(memberCount);
  };

  const handleKeyUp = (evt) => {
    const value = evt.target.value;
    if (evt.keyCode === 13 && !evt.shiftKey) {
      const chat = { user: activeUser, message: value, timestamp: +new Date() };
      evt.target.value = '';
      axios.post('http://localhost:8000/message', chat);
    }
  };

  return activeUser ? (
    <>
      <ChatInterface
        activeUser={activeUser}
        count={count}
        chats={chats}
        handleKeyUp={handleKeyUp}
        bottomRef={bottomRef}
      />
    </>
  ) : null;
}

There are similarities here to our PubNub component which matches this. We can subscribe to the channels, publish different messages and handle the presence. Although all of this is now done via the backend which now also works with basic authentication. Unlike the PubNub version however this version can accurately see how many users are online as well as when users are active, join and leave the group chat.

An authentication route is present for authenticating users and we incorporated a message route for posting all messages to our server.

Our frontend is almost completed just one file remains so add this code to our pusher.page.js file now:

'use client';
import Header from '../components/Header';
import UserLogin from '../components/UserLogin';

export default function Pusher() {
  return (
    <div>
      <Header />
      <UserLogin bgColor={'bg-emerald-800 '} appName={'Pusher Chat'} />
    </div>
  );
}

This file ensures that our Pusher version has a working route. All thats left is to get the messaging app up and running when we do the server file next.

Before we do that we should setup our run script in our package.json file so add this script to it:

"scripts": {
"start": "node index.js"
},

Alright, last file! Add this code to our index.js file in the server folder so we can complete the backend:

const cors = require('cors');
const Pusher = require('pusher');
const express = require('express');
require('dotenv').config();
const crypto = require('crypto');
const dev = process.env.NODE_ENV !== 'production';
const port = process.env.PORT || 8000;

const pusher = new Pusher({
  appId: process.env.PUSHER_APP_ID,
  key: process.env.PUSHER_APP_KEY,
  secret: process.env.PUSHER_APP_SECRET,
  cluster: process.env.PUSHER_APP_CLUSTER,
  useTLS: true,
});

const server = express();
server.use(cors());
server.use(express.json());
server.use(express.urlencoded({ extended: false }));

const chatHistory = { messages: [] };

server.post('/message', (req, res) => {
  const { user = null, message = '', timestamp = +new Date() } = req.body;
  const chat = { user, message, timestamp };
  chatHistory.messages.push(chat);
  pusher.trigger('presence-chatroom', 'new-message', { chat });
  res.status(200).send('Message sent successfully.');
});
server.post('/messages', (req, res) => {
  res.json({ ...chatHistory, status: 'success' });
});

server.post('/auth', (req, res) => {
  const socketId = req.body.socket_id;
  const channel = req.body.channel_name;
  console.log('Socket and channel', socketId, channel);
  const userId = crypto.randomBytes(8).toString('hex');

  const presenceData = {
    user_id: userId,
    user_info: {
      name: 'Anonymous User',
    },
  };

  const auth = pusher.authorizeChannel(socketId, channel, presenceData);
  res.send(auth);
});

server.listen(port, (err) => {
  if (err) throw err;
  console.log(`Server is running on port: ${port} http://localhost:${port}`);
});

Just a quick run through of this file so we can understand how it works. If you don't know its an Express server file which can connect to the Pusher API and it has routes for the authentication, message posting, in addition to getting chat history for all messages.

For connectivity, cors is implemented, so we don't get any of those annoying errors when trying to connect to different servers. The crypto module is used to doing various tasks like hash generation and encrypting and decrypting data.

With our codebase at MVP status, all you have to do is run the backend server in a different terminal window with the following command as shown below:

npm run start

So our server will run on port 8000 and you can change this in the server code if need be. Of course our Next.js application runs on port 3000, they need to be on different ports for obvious reasons. You already know how to use the PubNub version, the Pusher version works much the same.

Congratulations you have reached the end of this tutorial and created a working real-time messaging application!

Conclusion

Thats it we have completed the tutorial, learned about both real-time messaging applications and built a working demo application. As you have learned both platforms offer a similar feature set although Pusher has self-hosted and cloud options whereas PubNub offers only the later.

Ultimately your choice of platform will come down to what you make of their pros and cons. They have a free plan, so testing them is pretty easy to do. Pusher has flexible pricing in contrast to PubNubs strict pricing that offers much cheaper starter options priced at $98 compared to $49 for the Pusher startup option.