Modern applications are expected to do more than store and retrieve data. Users now want instant updates, live dashboards, and interactive experiences that react as events unfold. Whether it is a chat app showing new messages, a stock trading platform streaming market data, or a logistics dashboard updating delivery status in real time, the ability to generate and deliver insights instantly has become a core requirement.

These real-time systems are best powered by Node.js. It is the best option for applications requiring fast data transfer between servers, APIs, and clients due to its event-driven architecture, non-blocking I/O, and extensive package ecosystem. In this article, we will explore how Node.js can be used to deliver real-time insights, discuss common patterns, and build code examples you can use in your own projects.

Why Node.js is a Great Fit for Real-Time Systems?
Event-driven architecture
Real-time systems rely heavily on responding to events like new messages, sensor updates, or user actions. Node.js uses an event loop that can efficiently handle large numbers of concurrent connections without getting stuck waiting for blocking operations.

WebSocket support
Traditional HTTP is request-response-based. Real-time applications need continuous communication. Node.js pairs naturally with libraries such as Socket.IO or the native ws library to enable bidirectional, persistent communication channels.

Scalability
With asynchronous I/O and clustering options, Node.js can scale to handle thousands of active connections, which is common in real-time systems like multiplayer games or live dashboards.

Ecosystem
Node.js has packages for almost any use case: databases, analytics, messaging queues, and streaming. This makes it straightforward to combine real-time data ingestion with data processing and client delivery.

Common Use Cases of Real-Time Insights
Dashboards and Analytics
Business users rely on dashboards that display the latest KPIs and metrics. Node.js can connect directly to data streams and push updates to the browser.

IoT Monitoring
Devices can emit status updates or telemetry data. A Node.js backend can ingest this data and provide insights like anomaly detection or alerts.

Collaboration Tools
Tools like Slack, Google Docs, or Trello rely on real-time updates. Node.js makes it easy to propagate changes instantly to connected users.

E-commerce and Logistics
Real-time order tracking or inventory status requires continuous updates to customers and admins.

Finance and Trading
Traders depend on real-time updates for prices, portfolio values, and risk metrics. Node.js can handle fast streams of updates efficiently.

Building Blocks of Real-Time Insights in Node.js
Delivering real-time insights usually involves three layers:

Data Ingestion
Collecting raw data from APIs, databases, devices, or user actions.

Processing and Analytics
Transforming raw data into actionable insights, often with aggregations, rules, or machine learning.

Delivery
Sending updates to clients using WebSockets, Server-Sent Events (SSE), or push notifications.

Example 1. Real-Time Dashboard With Socket.IO
Let us build a simple dashboard that receives updates from a server and displays them in the browser. We will simulate incoming data to show how real-time delivery works.
Server (Node.js with Express and Socket.IO)
// server.js
const express = require("express");
const http = require("http");
const { Server } = require("socket.io");

const app = express();
const server = http.createServer(app);
const io = new Server(server);

app.get("/", (req, res) => {
  res.sendFile(__dirname + "/index.html");
});

// Emit random data every 2 seconds
setInterval(() => {
  const data = {
    users: Math.floor(Math.random() * 100),
    sales: Math.floor(Math.random() * 500),
    time: new Date().toLocaleTimeString()
  };
  io.emit("dashboardUpdate", data);
}, 2000);

io.on("connection", (socket) => {
  console.log("A client connected");
  socket.on("disconnect", () => {
    console.log("A client disconnected");
  });
});

server.listen(3000, () => {
  console.log("Server running on http://localhost:3000");
});

Client (HTML with Socket.IO client)
<!DOCTYPE html>
<html>
  <head>
    <title>Real-Time Dashboard</title>
    <script src="/socket.io/socket.io.js"></script>
  </head>
  <body>
    <h2>Live Dashboard</h2>
    <div id="output"></div>

    <script>
      const socket = io();
      const output = document.getElementById("output");

      socket.on("dashboardUpdate", (data) => {
        output.innerHTML = `
          <p>Users Online: ${data.users}</p>
          <p>Sales: ${data.sales}</p>
          <p>Time: ${data.time}</p>
        `;
      });
    </script>
  </body>
</html>

This small example shows the power of real-time insights. Every two seconds, the server pushes new data to all connected clients. No page refresh is required.

Example 2. Streaming Data From an API

Suppose we want to fetch cryptocurrency prices in real time and show insights to connected clients. Many crypto exchanges provide WebSocket APIs. Node.js can subscribe to these streams and forward updates.

// crypto-stream.js
const WebSocket = require("ws");
const express = require("express");
const http = require("http");
const { Server } = require("socket.io");

const app = express();
const server = http.createServer(app);
const io = new Server(server);

app.get("/", (req, res) => {
  res.sendFile(__dirname + "/crypto.html");
});

// Connect to Binance BTC/USDT WebSocket
const binance = new WebSocket("wss://stream.binance.com:9443/ws/btcusdt@trade");

binance.on("message", (msg) => {
  const trade = JSON.parse(msg);
  const price = parseFloat(trade.p).toFixed(2);
  io.emit("priceUpdate", { symbol: "BTC/USDT", price });
});

server.listen(4000, () => {
  console.log("Crypto stream running on http://localhost:4000");
});

Client (crypto.html)

<!DOCTYPE html>
<html>
  <head>
    <title>Crypto Prices</title>
    <script src="/socket.io/socket.io.js"></script>
  </head>
  <body>
    <h2>Live BTC Price</h2>
    <div id="price"></div>

    <script>
      const socket = io();
      const priceDiv = document.getElementById("price");

      socket.on("priceUpdate", (data) => {
        priceDiv.innerHTML = `Price: $${data.price}`;
      });
    </script>
  </body>
</html>

This example connects to Binance’s live WebSocket API and streams Bitcoin price updates to all clients in real time.

Example 3. Real-Time Analytics With Aggregation
Streaming raw events is useful, but real-time insights often require processing data first. For example, counting user clicks per minute or calculating moving averages.

// analytics.js
const express = require("express");
const http = require("http");
const { Server } = require("socket.io");

const app = express();
const server = http.createServer(app);
const io = new Server(server);

let clicks = 0;

// Track clicks from clients
io.on("connection", (socket) => {
  socket.on("clickEvent", () => {
    clicks++;
  });
});

// Every 5 seconds calculate insights and reset counter
setInterval(() => {
  const insights = {
    clicksPer5Sec: clicks,
    timestamp: new Date().toLocaleTimeString()
  };
  io.emit("analyticsUpdate", insights);
  clicks = 0;
}, 5000);

server.listen(5000, () => {
  console.log("Analytics server running on http://localhost:5000");
});

On the client side, you would emit clickEvent whenever a button is clicked, and display the aggregated insights in real time. This shows how Node.js can move beyond raw data delivery into live analytics.

Best Practices for Real-Time Insights in Node.js
Use Namespaces and Rooms in Socket.IO
This prevents all clients from receiving all updates. For example, only send updates about “BTC/USDT” to clients subscribed to that pair.

Throttle and Debounce Updates
If data arrives very frequently, throttle emissions to avoid overwhelming clients.

Error Handling and Reconnection
Networks are unreliable. Always handle disconnects and implement automatic reconnection logic on the client.

Security and Authentication
Never broadcast sensitive data without verifying client identities. Use JWTs or session-based auth with your real-time connections.

Scalability
For large systems, use message brokers like Redis, Kafka, or RabbitMQ to manage data streams between services. Socket.IO has adapters that integrate with Redis for horizontal scaling.

Conclusion

Real-time insights are no longer a luxury; they are a necessity in modern applications. From dashboards to trading platforms, from IoT devices to collaboration tools, users expect instant visibility into what is happening.

Node.js is one of the best tools to deliver this. Its event-driven architecture, excellent WebSocket support, and ecosystem of libraries make it easy to ingest, process, and deliver data at high speed.

The examples above only scratch the surface. You can extend them with authentication, persistence, analytics, or integrations with machine learning models. What matters is the pattern: ingest data, process it, and deliver insights continuously.

By combining Node.js with thoughtful design patterns, you can create applications that feel alive, responsive, and genuinely helpful to users. That is the promise of real-time insights, and Node.js gives you the foundation to build them.

It can be tempting to jump right into coding features and solely testing them by hand when you first start developing applications in Node.js. Small projects may benefit from this, but as your codebase expands, it soon becomes an issue. When you add new features, existing ones break, bugs occur, and manual testing slows down.

Test-driven development, or TDD, is useful in this situation. TDD is the process of writing a test for a feature, seeing it fail, writing the code to pass it, and then cleaning up your implementation while maintaining a green test score. This cycle pushes you to consider your code's purpose carefully before writing it.

This post will explain how to set up a Node.js project for TDD, write the initial tests, and use Jest and Supertest to create a basic API. You will have a useful workflow at the end that you may use for your own projects.

Why TDD Matters in Node.js?
Node.js is often used for building backends and APIs. These systems typically interact with databases, handle multiple requests, and address edge cases such as invalid inputs or timeouts. If you rely only on manual testing, it is very easy to miss hidden bugs.

With TDD, you get:

• Confidence that your code works as expected.
• Documentation of your intended behavior through test cases.
• Refactoring freedom, since you can change implementation details while ensuring nothing breaks.
• Fewer regressions because tests catch mistakes early.

Let us start building a small project using this approach.

Step 1. Setting Up the Project
Create a new folder for the project and initialize npm:
mkdir tdd-node-example
cd tdd-node-example
npm init -y

This creates a package.json file that will hold project metadata and dependencies.

Now install Jest, which is a popular testing framework for Node.js:
npm install --save-dev jest

Also, install Supertest, which will help us test HTTP endpoints:
npm install --save-dev supertest

To make things easier, add a test script in package.json:
{
  "scripts": {
    "test": "jest"
  }
}

This allows you to run tests with npm test.

Step 2. Writing the First Failing Test

Let us create a simple module that manages a list of tasks, similar to a basic to-do list. Following TDD, we will start with the test.

Inside a tests folder, create taskManager.test.js:
const TaskManager = require("../taskManager");

describe("TaskManager", () => {
  it("should add a new task", () => {
    const manager = new TaskManager();
    manager.addTask("Learn TDD");
    const tasks = manager.getTasks();
    expect(tasks).toContain("Learn TDD");
  });
});

We have not written taskManager.js yet, so that this test will fail. That is the point.

Run the test:
npm test

Jest will complain that ../taskManager it cannot be found. That confirms we need to write the implementation.

Step 3. Making the Test Pass
Now create taskManager.js at the root:
class TaskManager {
  constructor() {
    this.tasks = [];
  }

  addTask(task) {
    this.tasks.push(task);
  }

  getTasks() {
    return this.tasks;
  }
}

module.exports = TaskManager;

Run npm test again. This time the test passes. Congratulations, you just completed your first TDD cycle: red → green.

Step 4. Adding More Tests
Now, let us expand our tests. Modify taskManager.test.js:
const TaskManager = require("../taskManager");

describe("TaskManager", () => {
  it("should add a new task", () => {
    const manager = new TaskManager();
    manager.addTask("Learn TDD");
    expect(manager.getTasks()).toContain("Learn TDD");
  });

  it("should remove a task", () => {
    const manager = new TaskManager();
    manager.addTask("Learn Jest");
    manager.removeTask("Learn Jest");
    expect(manager.getTasks()).not.toContain("Learn Jest");
  });

  it("should return an empty list initially", () => {
    const manager = new TaskManager();
    expect(manager.getTasks()).toEqual([]);
  });
});

Now rerun the tests. The one for removeTask will fail since we have not implemented it.

Update taskManager.js:
class TaskManager {
  constructor() {
    this.tasks = [];
  }

  addTask(task) {
    this.tasks.push(task);
  }

  removeTask(task) {
    this.tasks = this.tasks.filter(t => t !== task);
  }

  getTasks() {
    return this.tasks;
  }
}

module.exports = TaskManager;

Run npm test again. All tests pass. Notice how the tests guided the implementation.

Step 5. Refactoring Safely
One beauty of TDD is that you can refactor with confidence. For example, we could change how tasks are stored internally. Maybe instead of an array, we want a Set to avoid duplicates.

Update the class
class TaskManager {
  constructor() {
    this.tasks = new Set();
  }

  addTask(task) {
    this.tasks.add(task);
  }

  removeTask(task) {
    this.tasks.delete(task);
  }

  getTasks() {
    return Array.from(this.tasks);
  }
}

module.exports = TaskManager;

Run the tests again. If they all pass, you know your refactor did not break behavior.

Step 6. Testing an API with Jest and Supertest
Unit tests are important, but most Node.js applications expose APIs. Let us use Express and Supertest to apply TDD to an endpoint.

First, install Express:
npm install express

Create app.js:
const express = require("express");
const TaskManager = require("./taskManager");

const app = express();
app.use(express.json());

const manager = new TaskManager();

app.post("/tasks", (req, res) => {
  const { task } = req.body;
  manager.addTask(task);
  res.status(201).json({ tasks: manager.getTasks() });
});

app.get("/tasks", (req, res) => {
  res.json({ tasks: manager.getTasks() });
});

module.exports = app;

Now, create a test file tests/app.test.js:
const request = require("supertest");
const app = require("../app");

describe("Task API", () => {
  it("should add a task with POST /tasks", async () => {
    const response = await request(app)
      .post("/tasks")
      .send({ task: "Write tests" })
      .expect(201);

    expect(response.body.tasks).toContain("Write tests");
  });

  it("should return all tasks with GET /tasks", async () => {
    await request(app).post("/tasks").send({ task: "Practice TDD" });

    const response = await request(app)
      .get("/tasks")
      .expect(200);

    expect(response.body.tasks).toContain("Practice TDD");
  });
});

Run npm test. Both tests should pass, confirming that our API works.

To actually run the server, create server.js:
const app = require("./app");

const PORT = 3000;
app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

Now you can try node server.js to use a tool like Postman or curl to send requests.

Step 7. Common Pitfalls in TDD
Writing too many trivial tests: Do not test things like whether 2 + 2 equals 4. Focus on meaningful business logic.

• Forgetting the cycle: Always follow the red → green → refactor cycle. Jumping ahead can lead to sloppy tests.
• Slow tests: Keep unit tests fast. If you hit a database or external API, use mocks or stubs.
• Unclear test names: Use descriptive test names that act as documentation.

Step 8. Best Practices

• Keep your tests in a separate tests folder or alongside the files they test.
• Run tests automatically before pushing code. You can set up a Git hook or CI pipeline.
• Use coverage tools to measure how much of your code is tested. With Jest, run npm test -- --coverage.
• Write tests that are independent of each other. Do not let one test rely on data from another.

Conclusion
Test-driven development with Node.js may feel slow at first, but it quickly pays off by giving you confidence in your code. By starting with a failing test, writing just enough code to pass, and then refactoring, you create a safety net that allows you to move faster in the long run. We walked through setting up Jest, writing unit tests for a TaskManager class, refactoring safely, and even testing API endpoints using Supertest. The process is the same no matter how big your application grows.

If you are new to TDD, begin small. Write a few tests for a utility function or a simple route. With practice, the habit of writing tests before code will become second nature, and your Node.js projects will be more reliable and easier to maintain.

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Most developers were unaware that Node.js would change the way web apps are created when it initially surfaced in 2009. These days, it powers anything from platforms used by millions of people globally to small personal projects. This post will examine how Node.js transformed web development, its popularity, and its implications for developers looking to create cutting-edge, quick apps.

The State of Web Development Before Node.js
Before Node.js, building web applications usually required separate technologies for the frontend and backend. The frontend ran in the browser using JavaScript, while the backend relied on languages like PHP, Java, Ruby, or Python. This separation often created friction because developers had to switch between different programming languages, ecosystems, and tools.

Backends were also synchronous by nature in most environments. Each request was processed in order, and if one operation took time, such as reading from a database, the system had to wait before moving on to the next task. This limited how many requests a server could handle at once.
What Node.js Brought to the Table

Node.js changed this picture in three big ways:

• JavaScript Everywhere: Developers could now use the same language on both the frontend and backend. This made it easier for teams to share knowledge and code.
• Non-blocking I/O: Node.js uses an event-driven, asynchronous model. This means it can handle thousands of requests at the same time without getting stuck waiting for one task to finish.
• Huge Ecosystem: The Node Package Manager (NPM) quickly became one of the largest software ecosystems in the world, with millions of packages that help developers build faster.

The Event-Driven Model Explained
At the core of Node.js is its event loop. Instead of processing requests one by one, Node.js listens for events and responds as soon as it can. This is why it is so good at handling applications that require many concurrent connections, like chat apps, live dashboards, or streaming services.

Here is a simple example:
const http = require('http');

const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello from Node.js\n');
});

server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});

This small script creates a working web server with just a few lines of code. Compare this to older backends, where setting up a basic server required much more boilerplate.

Asynchronous Programming in Action
Node.js relies heavily on callbacks, promises, and async/await to manage asynchronous tasks. For example, reading a file in Node.js does not block the entire application:
const fs = require('fs');

fs.readFile('data.txt', 'utf8', (err, data) => {
  if (err) {
    console.error('Error reading file:', err);
    return;
  }
  console.log('File contents:', data);
});

console.log('Reading file...');

When you run this code, “Reading file...” prints before the actual file contents. That is because Node.js starts reading the file, but does not pause the rest of the program. This makes applications more efficient.

With modern JavaScript, developers can write the same logic using async/await for cleaner code:
const fs = require('fs').promises;

async function readFile() {
  try {
    const data = await fs.readFile('data.txt', 'utf8');
    console.log('File contents:', data);
  } catch (err) {
    console.error('Error reading file:', err);
  }
}

readFile();

Real-Time Applications
One of the biggest impacts of Node.js is in real-time web applications. Before Node.js, creating a chat app or live notifications system often required hacks like long polling, which were inefficient. With Node.js and libraries like Socket.IO, developers can easily build real-time communication.

Example of a simple chat server:
const http = require('http');
const socketIo = require('socket.io');

const server = http.createServer();
const io = socketIo(server);

io.on('connection', (socket) => {
  console.log('A user connected');

  socket.on('message', (msg) => {
    console.log('Message received:', msg);
    io.emit('message', msg);
  });

  socket.on('disconnect', () => {
    console.log('User disconnected');
  });
});

server.listen(3000, () => {
  console.log('Chat server running on http://localhost:3000');
});

With just a few lines of code, you now have a chat server capable of handling multiple users at once. This ease of building real-time features is one reason Node.js became a favorite in the developer community.

The Rise of Full-Stack JavaScript
Another big change Node.js brought is the rise of the “JavaScript everywhere” philosophy. With Node.js on the backend and frameworks like React or Vue on the frontend, developers could use a single language across the entire stack. This gave birth to the role of the full-stack JavaScript developer.

Frameworks like Express.js made building web servers easier and more structured. For example:
const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Welcome to my Node.js app!');
});

app.listen(3000, () => {
  console.log('App running on http://localhost:3000');
});

Express quickly became the go-to framework for Node.js applications and laid the foundation for other tools like NestJS, Fastify, and Hapi.

Microservices and Node.js
As applications grew larger, companies started moving from monolithic designs to microservices. Node.js fits perfectly into this architecture because it is lightweight, fast, and scalable. Developers could create small independent services, each handling a specific task, and connect them together.

This made it easier to scale parts of the system independently. For example, an e-commerce site might have one service for handling user authentication, another for payments, and another for product listings. Node.js helped companies like Netflix, Uber, and PayPal move to microservices successfully.

NPM and the Power of Community
Another reason Node.js changed web development is its ecosystem. NPM grew into the largest collection of open-source libraries in the world. Instead of reinventing the wheel, developers could install packages to handle almost any task, from authentication to image processing.

Example of installing a package:
npm install axios

And then using it in your app:
const axios = require('axios');

async function fetchData() {
  const res = await axios.get('https://jsonplaceholder.typicode.com/posts/1');
  console.log(res.data);
}

fetchData();

This speed of development and access to community-driven code drastically reduced the time it takes to build applications.

Performance and Scalability
One of the key reasons big companies adopted Node.js is performance. Its non-blocking I/O and lightweight design make it well-suited for high-traffic applications. For example, Netflix uses Node.js to handle millions of users at the same time while reducing startup time for its applications.

Node.js applications can also scale horizontally by running multiple instances across servers. This flexibility made it one of the most reliable tools for modern web infrastructure.

The Human Side of Node.js
Beyond the technology, Node.js changed how developers work together. Teams no longer need separate specialists for frontend and backend. A single JavaScript team could handle the entire product lifecycle. This made collaboration easier and reduced miscommunication.

It also opened doors for beginners. Learning one language, JavaScript, is enough to start building both client and server code. This lowered the entry barrier for people new to web development.

Conclusion
Node.js did more than just provide a new runtime for JavaScript. It transformed how developers build, scale, and think about web applications. From real-time communication to microservices and from frontend to backend unification, Node.js brought speed, flexibility, and simplicity to the web. The next time you use a streaming platform, ride-sharing app, or live chat feature, there is a good chance Node.js is working behind the scenes. For developers, it continues to be a powerful tool that simplifies complex tasks and makes building modern web applications faster and more enjoyable.

There are APIs everywhere. They power every program you use, including Netflix, Uber, and Slack. Additionally, developers have more backend alternatives than ever in 2025 thanks to serverless platforms, AI-driven frameworks, Go, Rust, Bun, and Deno. The truth is, though, that Node.js remains one of the top tools for creating APIs. It is dependable in delivering speed, ecosystem, and scalability—not because it is the newest or most ostentatious.

Let's examine what Node.js still excels at using actual examples that you can copy and paste right now.

1. Quick Builds with Express
Express isn’t trendy anymore, but it still excels at one job: getting APIs running quickly.
import express from "express";

const app = express();
app.use(express.json());

app.get("/hello", (req, res) => {
  res.json({ message: "Hello from Node.js 2025!" });
});

app.post("/user", (req, res) => {
  const { name, email } = req.body;
  res.status(201).json({ id: Date.now(), name, email });
});

app.listen(3000, () => console.log("API running on http://localhost:3000"));

That’s an API in under 10 lines of code. If you need to validate an idea, ship a prototype, or power a small project, Express is still unbeatable.

2. Structure at Scale with NestJS
If Express is quick-and-dirty, NestJS is clean-and-scalable.
It’s TypeScript-first, opinionated (in a good way), and feels like Spring Boot for Node.js. Perfect when your project grows beyond a few routes.
import { Controller, Get, Post, Body } from '@nestjs/common';

@Controller('users')
export class UserController {
  private users = [];

  @Get()
  getAllUsers() {
    return this.users;
  }

  @Post()
  createUser(@Body() body: { name: string; email: string }) {
    const newUser = { id: Date.now(), ...body };
    this.users.push(newUser);
    return newUser;
  }
}

With NestJS, you get decorators, dependency injection, and modular architecture, the stuff enterprise APIs love.

3. Real-Time APIs with Socket.IO
This is where Node.js really shines. Its event-driven nature makes it perfect for real-time APIs like chat apps, dashboards, and notifications.
import express from "express";
import { createServer } from "http";
import { Server } from "socket.io";

const app = express();
const server = createServer(app);
const io = new Server(server);

io.on("connection", (socket) => {
  console.log("User connected:", socket.id);

  socket.on("send_message", (msg) => {
    io.emit("receive_message", msg); // broadcast
  });

  socket.on("disconnect", () => {
    console.log("User disconnected:", socket.id);
  });
});

server.listen(4000, () => console.log("Realtime API on port 4000"));

Building this kind of API in some other languages takes heavy libraries or boilerplate. With Node.js, it’s natural.

4. npm: The Unmatched Ecosystem
In 2025, npm is still the largest package ecosystem out there.

Need authentication? Payments? File uploads? There’s an npm package for it.

Stripe integration, for example, is still easiest in Node.js:
import express from "express";
import Stripe from "stripe";

const stripe = new Stripe(process.env.STRIPE_SECRET);
const app = express();

app.post("/checkout", async (req, res) => {
  const session = await stripe.checkout.sessions.create({
    payment_method_types: ["card"],
    mode: "payment",
    line_items: [{ price: "price_123", quantity: 1 }],
    success_url: "https://example.com/success",
    cancel_url: "https://example.com/cancel",
  });

  res.json({ url: session.url });
});

app.listen(3000, () => console.log("Stripe API running"));

This ecosystem advantage is why many teams stick with Node.js over newer runtimes.

5. Node.js vs Bun vs Deno
Yes, Bun is blazing fast. Yes, Deno fixed security defaults. But in production-readiness, Node.js is still ahead.

• Battle-tested: Millions of production apps.
• Ecosystem: Most libraries target Node.js first.
• Community: It’s easier to find Node.js devs than Bun/Deno experts.

For cutting-edge hobby projects, try Bun or Deno. For real-world APIs that need to last? Node.js is the safe bet.

6. Scaling with Workers & Clusters
Node.js isn’t just “single-threaded” anymore. With workers and clusters, it scales across CPU cores.
import cluster from "cluster";
import os from "os";
import express from "express";

if (cluster.isPrimary) {
  const numCPUs = os.cpus().length;
  console.log(`Starting ${numCPUs} workers...`);
  for (let i = 0; i < numCPUs; i++) cluster.fork();
} else {
  const app = express();
  app.get("/", (req, res) => res.send("Hello from worker " + process.pid));
  app.listen(3000, () => console.log(`Worker ${process.pid} running`));
}

This means Node.js can handle heavy workloads without breaking a sweat.
Final Thoughts
Node.js isn’t the shiny new toy anymore. But when it comes to APIs in 2025, it’s still one of the best choices:

• Express for speed.
• NestJS for structure.
• Socket.IO for real-time.
• npm for integrations.
• Workers & clusters for scale.

Other runtimes may grab headlines, but Node.js is still the sweet spot between developer productivity and production reliability. If you’re building APIs in 2025, don’t sleep on Node.js. It’s not just alive, it’s thriving.

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In Node.js, what is a buffer?
In Node.js, raw binary data is stored in a specific object called a buffer. Buffers hold bytes, as opposed to strings, which represent text characters. For managing big files, network data, or any non-text data, this makes them extremely helpful.

For instance

Example
const buf = Buffer.from('Hello, Node.js');
console.log(buf);
console.log(buf.toString());

Buffers store data in bytes, which can later be converted to readable text using toString().

When to Use a Buffer?
Buffers are helpful in situations where you need to handle binary data efficiently:

Reading and writing files: especially large files.
Handling network packets: when sending or receiving data over sockets.
Working with streams: processing data in small chunks.
Processing images, audio, or video data: when raw byte manipulation is needed.

Example: Reading a File Using Buffer

Example
const fs = require('fs');

fs.readFile('example.txt', (err, data) => {
  if (err) throw err;
  console.log('Buffer content:', data); // Shows raw bytes
  console.log('As string:', data.toString()); // Converts to text
});

Node.js reads the file as a buffer first, allowing you to process the raw bytes or convert them to a string.

Buffer vs String

• Buffer: Stores raw bytes; suitable for any kind of data.
• String: Stores characters; best for readable text.

Example
const str = 'Hello';
const buf = Buffer.from(str);

console.log('String length:', str.length);
console.log('Buffer length:', buf.length);

Buffers are more flexible than strings when working with non-text data or large datasets.

Summary
A Buffer in Node.js is used to store and manipulate raw binary data efficiently. It is especially useful for reading and writing files, handling network data, working with streams, and processing multimedia files. Unlike strings, buffers can handle any type of data, making Node.js applications faster and more memory-efficient.

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The cornerstone of online application security is authentication. The authentication environment in MERN (MongoDB, Express.js, React, and Node.js) stack apps is dominated by two popular methods: two methods of authentication: session-based and token-based. Although they both accomplish the same objective—verifying a user's identity and safeguarding resources their implementation, application cases, and scalability are very different. This page describes each approach, how it functions in a MERN setting, and why it is better to use one over the other.

What is Authentication?
Before we dive in, let’s clarify.

• Authentication: confirming the identity of the user (Are you who you say you are?)
• Authorization: controlling access to resources (What can you do now that you're authenticated?)

Overview of Authentication Methods

Session-Based Authentication (Cookie-Based)

How does it work?

• User submits credentials via lthe ogin form.
• Backend verifies and creates a session, saving it on the server (in memory, Redis, or DB).
• Server returns a session ID in a secure HTTP-only cookie.
• On each request, the browser sends the session ID via cookie.
• Server looks up session data using the ID and verifies the user.

Where does it fit in MERN?

• React: The frontend sends login requests and automatically includes cookies on future requests (if configured correctly).
• Express/Node.js: Stores sessions using express-session or similar libraries.
• MongoDB: Often used with a session store like connect-mongo.

Security Features

• HttpOnly cookies protect against XSS.
• Cookies can be set to SameSite, Secure, and have expiry times.

Drawbacks

• Needs server-side storage (memory or DB).
• Less ideal for horizontal scaling unless using a centralized session store (e.g., Redis).
• Slightly more complex to manage in APIs for SPAs or mobile apps.

Token-Based Authentication (JWT)
How does it work?

• User logs in with credentials.
• Server verifies and returns a signed token (usually JWT).
• Token is stored on the client (localStorage, sessionStorage, or cookie).
• On each request, a token is sent in headers (commonly in Authorization: Bearer <token>).
• Server validates token signature and grants access.

Where does it fit in MERN?

• React: Stores token in localStorage or cookies, attaches it to API requests using Axios or Fetch.
• Express/Node.js: Verifies token with jsonwebtoken or similar libraries.
• MongoDB: Optionally stores refresh tokens for session control.

Security Features

• Tokens can be signed with a secret or private key.
• Supports token expiration (exp), issued at (iat), and more.

Drawbacks

• If stored in localStorage, vulnerable to XSS attacks.
• No built-in logout mechanism (tokens are self-contained).
• Revocation is difficult without additional mechanisms (blacklists, short expiration with refresh tokens).

Comparison Table

When to Use What?

Use Session-Based Authentication When

• You’re building a server-rendered web app (e.g., admin dashboard).
• You control both client and server and want automatic cookie handling.
• You need simple session invalidation (e.g., logging users out remotely).
• You can scale horizontally with a session store like Redis.

Use Token-Based Authentication (JWT) When?

• You’re building a single-page application (SPA) with React.
• You want to support mobile apps or third-party clients.
• You prefer a stateless API that’s easy to scale.
• You want users to remain authenticated across multiple domains/services (microservices).

Session + Token Hybrid Approach (Best of Both Worlds)
Many modern apps use a hybrid approach.

• Store the JWT in an HttpOnly cookie (safer from XSS).
• Use refresh tokens with short-lived access tokens.
• Server can keep track of refresh tokens to allow logout.

This combines the statelessness of tokens with the security of sessions.

Final Thoughts
There’s no one-size-fits-all approach to authentication in the MERN stack. Your decision depends on.

• Application type (SPA, mobile, or SSR).
• Security requirements.
• Scalability and infrastructure.
• Developer experience and ease of maintenance.

Both session-based and token-based auth systems have matured. The best strategy in 2025 is to choose consciously based on your application’s architecture and implement it securely.

Conclusion
In the evolving world of full-stack development, especially in MERN applications, choosing the right authentication method is crucial for performance, security, and user experience. Session-based authentication remains reliable for traditional web apps where server-side session control is preferred. On the other hand, token-based authentication (JWT) is ideal for modern, stateless, API-driven applications like SPAs and mobile apps.

By understanding the trade-offs between these two approaches, developers can design authentication systems that are secure, scalable, and user-friendly. In many real-world scenarios, a hybrid approach combining short-lived tokens with secure cookies offers the best balance between security and flexibility.

Ultimately, the best choice is not about which method is superior - it's about which method aligns with your architecture, user experience goals, and scalability needs.

It's likely that Node.js is responsible for any websites that load really quickly or change in real time, such as chat apps or live scores. However, what is Node.js and how does its architecture contribute to its power? Let's put it in plain language.

What is Node.js?
Node.js is not a programming language or a framework; it’s a runtime environment. It enables developers to run JavaScript on the server side, outside of the browser. It’s built on Google Chrome’s V8 JavaScript engine, which makes it super fast.

e.g: "Hello World" in Node.js.
// Import the built-in 'http' module
const http = require('http');

// Create a simple server
const server = http.createServer((req, res) => {
  res.end('Hello World from Node.js!');
});

// Server listens on port 3000
server.listen(3000, () => {
  console.log('Server is running on http://localhost:3000');
});

This simple server handles HTTP requests using a single thread and responds with "Hello World". Even if 100 users open it at once, Node.js can manage that efficiently, thanks to its architecture.

Let’s break it down.

1. Single-Threaded Event Loop
Node.js uses a single thread to handle all client requests. That means it doesn’t create a new thread for every request like traditional web servers (such as Apache). Here the question comes.

Then, how does it handle multiple users simultaneously?

It supports multiple users simultaneously through its Event-Driven Architecture. Let's explore it.

2. Event-Driven Architecture
Imagine you are at a restaurant. Instead of the chef cooking only one dish at a time (waiting for it to finish before starting the next), he puts dishes in the oven and moves on to the next task. When the oven beeps, he knows the food is ready.

Our Node.js works in the same way.

• When a request (like fetching data or reading a file) comes in, it’s added to the event queue.
• Node.js doesn’t wait for the task to finish. Instead, it moves on to the next task.
• Once the task is completed, Node.js receives notification (via a callback function) and processes the result.

This makes Node.js extremely fast and efficient, particularly for I/O-Intensive tasks.

• Reading/writing files
• Talking to databases
• Calling APIs

3. Non-Blocking I/O

• Most web servers use blocking I/O, which means they wait for one operation to finish before moving to the next.
• Node.js uses non-blocking I/O, meaning it doesn’t wait for input. This allows Node.js to handle thousands of requests per second with a single thread.

Let's simulate a non-blocking operation, such as reading a file.
const fs = require('fs');

console.log('Start reading file...');

fs.readFile('example.txt', 'utf8', (err, data) => {
  if (err) {
    return console.error(err);
  }
  console.log('File content:', data);
});

console.log('Reading file initiated...');

Output

Key Components of Node.js Architecture
Here are the main parts that makeup Node.

Advantages of Node.js Architecture
Fast: Thanks to V8 and the non-blocking model.

• Scalable: Handles a large number of users without crashing or slowing down.
• Efficient: Great for real-time apps like chat, games, or live data.
• Lightweight: Uses fewer system resources compared to traditional servers.

When to Use Node.js?
Node.js is ideal for.

• Real-time apps (chat apps, online games)
• APIs for web/mobile apps
• Data streaming apps
• Single Page Applications (SPAs)

Conclusion
Node.js architecture is what makes it stand out. Its event-driven, non-blocking, and single-threaded design helps developers build fast, scalable, and efficient applications.

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Node Version Switcher, or NVS for short, is a cross-platform utility that may be used on Windows, Linux, and Mac workstations to manage several node versions on a single computer.

This program installs the various node versions in the Windows user profile folder without requiring administrator privileges on your workstation. Put otherwise, it won't interfere with the C:\Program Files or C:\System32 files.

Just like NVM (Node Version Manger)This tool manages all legacy and newer node versions independently and manages the runtime for you on the fly. As you see in the above screenshot, NVS can maintain multiple versions of node in same environment. Each version of the node can have its own tools and runtime.

The node is required for building SPFx (SharePoint Framework) solutions and building SPA (Single Page Applications) and many more.

Steps
Please follow the below steps to set up and configure NVS on windows workstation. Please note that all the steps are performed against windows 11 OS workstation
Step 1. Let us check if the workstation has NVS (Node Version Switcher) already installed.

Step 2. Let us try installing NVS on windows machine. In Windows 11, winget is already installed as part of OS and MSFT recommends using winget to install and maintain the software from Github repository. At first it is required to open the command prompt as administrator.

Step 3. in the CMD window, try running the below command to install the NVS. winget install jasongin.nvs –source winget

Step 4. Wait for the operation to complete. At the end you should be getting the message ‘Successfully installed’

Step 5. Close the command window. Open the command window again in ‘Administrator Mode’. This is required. Once opened type in ‘nvs’ in the command window. This time if you can see the nvs version numbers you are good and proceed to step 8. Else if you are getting the ‘Self signed certificate issue’ as per below screen capture then proceed to step 6.

Step 6. Copy the URL https://nodejs.org/dist/index.json in the chrome browser and download the certificate. Make sure you download file contains certificate chain. Click on the certificate information in browser.

Click on lock that says, ‘Connection is secure’.

Click on ‘Certificate is valid’

Click on the ‘Details’ tab.

Click on ‘Export Certificate’.

Step 7. Set up the environment variable for your profile under windows environment variables. Set the file for the environment variable to the certificate that you just downloaded.

Step 8. Open the command prompt as administrator and then type nvs and look for the below output.

Step 9. If you do not have any version installed, you will be asked to select the node versions from the available binaries. In this case I have chosen to install the version 18.20.6 by using the below command.

nvs add 10.20.6

Step 10. Once the installation starts you will be getting below message.

After couple of minutes, you should get a message that the specified node version is added.

Step 11. clear the screen and type I nvs, you should get the versions now. Select the required version.

Step 12: I have type in (a). you can select the one that is required for your needs. Once selected you can check the version by using the below command.

node –v

Conclusion
Thus, in this article, you have seen how to install NVS a cross-platform tool to manage multiple node versions efficiently, in windows workstation.

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A fundamental element of modern web development is the usage of live chat software to enable real-time user contact. Using technologies like Socket.IO and Node.js greatly simplifies the process. Socket.IO is a JavaScript library that allows bidirectional, real-time communication between web clients and servers, resulting in stable connections across all browsers. Node.js, a stable runtime environment that uses an event-driven, non-blocking I/O model, makes it simple to create scalable network applications.

Steps for Creating a Project]
Step 1. Setting Up the Project
Use my previous article for setting up Node.js, "How to upload file in Node.js" In this article, we mentioned important commands for uploading files in Node.js.

Step 2. Setting Up the Server
Create the Server File. Create a file named index.js
const express = require('express');
const app = express();
const { Server } = require('socket.io');
const http = require('http');
const server = http.createServer(app);
const io = new Server(server);
const port = 4000;
app.get('/', (req, res) => {
    res.sendFile(__dirname + '/index.html');
});
io.on('connection', (socket) => {
    socket.on('send name', (username) => {
        io.emit('send name', username);
    });
    socket.on('send message', (chat) => {
        io.emit('send message', chat);
    });
});
server.listen(port, () => {
    console.log(`Server is listening at the port: ${port}`);
});

Step 3. Creating the Frontend
Create the HTML File. Create a file named index.html
<!DOCTYPE html>
<html>
<head>
    <title>Chat app using Socket IO and Node JS</title>
    <script src="https://cdn.tailwindcss.com"></script>
    <style>
        h1 {
            color: #273c75;
        }

        .msg-box {
            display: flex;
            flex-direction: column;
            background: darkgray;
            padding: 20px;
        }
    </style>
</head>
<body>
    <h1 class="font-bold text-3xl text-center mt-5">
        C# Corner Chat App using Socket IO and Node JS
    </h1>
    <div>
    </div>
    <form class="flex flex-col justify-center items-center mt-5" id="form">
        <div class="msg-box">
            <input class="border border-gray-400 rounded-md mt-5 p-1" type="text" placeholder="Name" id="myname"
                autocomplete="off">
            <input class="border border-gray-400 rounded-md mt-5 p-1" type="text" placeholder="Message" id="message"
                autocomplete="off">
            <button class="bg-blue-500 rounded-md p-2 text-white mt-5">
                Send
            </button>
        </div>
    </form>
    <div class="flex flex-col justify-center items-center mt-5" id="messageArea">
    </div>
</body>
<script src="/socket.io/socket.io.js"></script>
<script>
    let socket = io();
    let form = document.getElementById('form');
    let myname = document.getElementById('myname');
    let message = document.getElementById('message');
    let messageArea = document.getElementById("messageArea");
    form.addEventListener("submit", (e) => {
        e.preventDefault();
        if (message.value) {
            socket.emit('send name', myname.value);
            socket.emit('send message', message.value);
            message.value = "";
        }
    });
    socket.on("send name", (username) => {
        let name = document.createElement("p");
        name.style.backgroundColor = "#a59494";
        name.style.textAlign = "center";
        name.style.color = "white";
        name.textContent = username + ":";
        messageArea.appendChild(name);
    });
    socket.on("send message", (chat) => {
        let chatContent = document.createElement("p");
        chatContent.textContent = chat;
        messageArea.appendChild(chatContent);
    });
</script>
</html>

Step 4. Running the Application
Run the command in CMD.
node index.js

In the output, you can open the chat application in two different browsers or different tabs. When you start typing and send a message, it reflects on both screens in real-time.

Conclusion
You have now successfully used Node.js and Socket.IO to develop a basic live chat application. This application facilitates real-time communication between users by rapidly reflecting messages across several linked clients. To make your app even better, think about including features like private messaging, user authentication, and database storage for conversation history. Using CSS frameworks or original designs to enhance the user interface can improve the user experience. Use Vercel or Heroku to launch your application for increased accessibility. Continue researching and experimenting to create a robust and feature-rich chat experience. Enjoy yourself while coding!

In contemporary web development, logging plays a crucial role in program monitoring and troubleshooting. Node.js offers a variety of logging tools for monitoring and analyzing application operations because of its event-driven architecture. This article will walk through how to build a logging system for a Node.js application using Winston, a versatile logging package, and Express, a popular web framework.

What is Logging?
The process of keeping track of activities and occurrences inside a software system is called logging. These log entries help with debugging, monitoring, auditing, and security. They include timestamps, severity levels, messages, and contextual data. Logging helps with performance analysis, intrusion detection, compliance adherence, and troubleshooting by capturing important information about system behavior. With their ability to provide insights into application flow, performance bottlenecks, user actions, and security concerns, logs are an indispensable tool for developers, administrators, and security professionals. Logging is essentially a basic procedure used in software development and operations that makes software systems easier to manage, secure, and monitor.

Why we use Logging?
Logging serves several essential purposes in software development:

• Debugging and Troubleshooting: Logs are an important source of information for troubleshooting and identifying difficulties with a program. To comprehend the execution flow, spot faults, and find the source of problems, developers can go through log messages.
• Monitoring and Performance Optimization: Developers may keep an eye on an application's performance in real time with the help of logs. Developers can pinpoint performance bottlenecks, maximize resource use, and raise the application's general effectiveness by examining log data.
• Auditing and Compliance: Keeping track of user actions and system events is facilitated by logging. For compliance with legal standards like GDPR, HIPAA, or PCI DSS, this audit trail is crucial. Logs are useful for monitoring user behavior, spotting illegal access, and guaranteeing the accuracy of data.
• Security and Intrusion Detection: When it comes to identifying security risks and unauthorized access attempts, logs are essential. Events including unsuccessful login attempts, questionable activity, and possible security breaches are recorded in security logs. Administrators are able to quickly identify and address security incidents by examining security logs.

Steps for Creating a Project
Step 1.  Setting Up the Project
Use my previous article for setting up Node.js, "How to upload file in Node.js" In this article, we mentioned important commands for uploading files in Node.js.

Step 2. Integrating Winston for Logging
Winston is a versatile Node.js logging package that supports many transports, such as file, database, and terminal. Winston will be set up to log messages to both the console and a log file at various levels (info, error, etc.).
// main.js

const winston = require('winston');

// Create a logger instance
const logger = winston.createLogger({
  level: 'info', // Logging level
  format: winston.format.json(), // Log format
  transports: [
    // Log to the console
    new winston.transports.Console(),
    // Log to a file
    new winston.transports.File({ filename: 'logging_file.log' })
  ]
});

Step 3.  Implementing Logging Middleware in Express
We are able to intercept and handle incoming requests thanks to express middleware. A unique middleware function will be developed to log incoming HTTP requests. Request methods, URLs, and other pertinent data will be recorded by this middleware and logged using Winston.
// Middleware to log requests
app.use((req, res, next) => {
  logger.log('info', `${req.method} ${req.url}`);
  next();
});

Step 4.  Creating Routes and Handling Errors
After installing logging middleware, we will create our Express application's routes. To show how to handle requests, we'll construct a simple route for the main page ("/"). Furthermore, error handling middleware will be implemented to log and manage any faults that arise during request processing.
// Route handling
app.get('/', (req, res) => {
  res.send('Hello, world!');
});

// Error handling middleware
app.use((err, req, res, next) => {
  logger.log('error', err.stack);
  res.status(500).send('Something broke!');
});

Step 5. Serving Log File via Web Interface
We'll develop an additional route ("/logs") that reads the contents of the log file and sends it to the client in order to give a user-friendly way for log files to be viewed. In order to ensure security and avoid dangerous infinite loops, this route will ignore logging requests so they are not kept in the log file.
// Route to serve log file
app.get('/logs', (req, res) => {
  fs.readFile('combined.log', 'utf8', (err, data) => {
    if (err) {
      logger.log('error', err);
      return res.status(500).send('Error reading log file');
    }
    res.type('text/plain').send(data);
  });
});

Step 6. Running the Application
Finally, let us launch our Express application and verify its operation. To start the HTTP request logging, start the server and visit the home page. You may also view the contents of the log file using the web interface by going to the "/logs" route.
node main.js

Output