How To Send Data From Your JavaScript Website to Apache Kafka

In today's data-driven world, businesses rely on efficient and real-time data processing to gain insights and provide seamless user experiences. Apache Kafka, a distributed streaming platform, has emerged as a powerful solution for handling high-throughput, fault-tolerant data streams. If you have a JavaScript website and want to leverage the capabilities of Apache Kafka to process and analyze your data, this tutorial will walk you through the process of sending data from your website to Kafka.

Understanding Apache Kafka and Its Role in Data Streaming

Before diving into the implementation details, let's first explore what Apache Kafka is and why it's so popular among developers. In simple terms, Apache Kafka is a distributed publish-subscribe messaging system that allows multiple applications to exchange data in real-time. It was initially developed at LinkedIn to handle their massive data streams, and has since grown into a widely adopted open source project.

What is Apache Kafka?

At its core, Apache Kafka is a distributed commit log, which means that it provides a record of all data changes and updates that occur within a system. This commit log is divided into multiple partitions and is stored on a cluster of servers, which allows for horizontal scalability and fault tolerance. Producers can write data to the Kafka cluster, while consumers can read that data and process it accordingly. Additionally, Kafka provides several APIs for various programming languages like Java, Python and Scala, making it easy to integrate with other applications and services.

One of the key features of Apache Kafka is its ability to handle large amounts of data with ease. This is due to its highly scalable architecture, which allows for the addition of more servers as needed to handle increased data loads. Additionally, Kafka is fault-tolerant, which means that even if one or more servers in the cluster go down, the system can continue to function without any data loss. This is achieved through the use of replication, where multiple copies of the data are stored on different servers.

Another benefit of using Apache Kafka for data streaming is its low latency. This means that data can be processed and delivered in real-time, making it ideal for use cases such as real-time data streaming and event processing. With Kafka, data can be processed and delivered within milliseconds, which is crucial for applications that require real-time data analysis and decision-making.

When it comes to configuring Apache Kafka, you have multiple options available, including setting it up locally using the open-source license or utilizing various SaaS (Software-as-a-Service) offerings. Here are three examples of SaaS services that provide managed Apache Kafka solutions:

  • Confluent Cloud: Confluent Cloud is a fully managed Kafka service provided by Confluent, the company founded by the creators of Apache Kafka. It offers a cloud-based platform that takes care of deploying, managing, and scaling Kafka clusters. Confluent Cloud provides features like automatic scaling, monitoring, security, and integration with other Confluent ecosystem components.
  • Upstash: Upstash is a cloud-native database platform that offers an integrated managed Kafka service. It allows you to set up and manage Kafka clusters effortlessly without worrying about infrastructure or operational tasks.
  • AWS Managed Streaming for Apache kafka: AWS MSK is a fully managed Kafka service provided by Amazon Web Services (AWS). It simplifies the deployment and management of Kafka clusters on the AWS platform. AWS MSK takes care of the underlying infrastructure, such as provisioning and scaling, while providing integration with other AWS services, like Amazon CloudWatch for monitoring and AWS Identity and Access Management (IAM) for security.

Note: You can learn more about the Apache Kafka project in this Github repository.

Use Cases for Apache Kafka

Apache Kafka is used in a wide range of applications and industries, including finance, healthcare, e-commerce, and social media. In finance, Kafka is used for real-time analysis of stock market data, while in healthcare it's used for monitoring patient vitals in real-time. E-commerce companies use Kafka to track customer behavior and make real-time recommendations, while social media companies use it for real-time processing of user-generated content.

Another use case for Apache Kafka is in the Internet of Things (IoT) space. With the proliferation of connected devices, there is a growing need for real-time data processing and analysis. Kafka can be used to collect and process data from these devices in real-time, enabling companies to make real-time decisions based on that data.

Setting Up Your JavaScript Website

Now that we have a basic understanding of what Apache Kafka is and why it's useful for data streaming, let's move on to setting up your JavaScript website. There are a few key decisions you'll need to make before beginning the implementation process.

Choosing the Right JavaScript Framework

Choosing the right JavaScript framework is an important decision when developing a website, as it can greatly impact the ease of integration with other services such as Apache Kafka. Some popular choices include React, Angular, and Vue for the front-end UI and Node JS for the backend, each with its own unique set of features and benefits. For this article, we'll be using NodeJS as our JavaScript framework.

Integrating Apache Kafka into Your JavaScript Website

Now that we have our website set up, and you’ve set up Kafka using one of the above methods, it's time to integrate Apache Kafka.

In Apache Kafka, a Kafka broker is a single instance of the Kafka server that serves as a message broker within a Kafka cluster. It is responsible for handling incoming data streams, storing and replicating messages across the cluster, and serving client requests.

First, you'll create a Kafka topic, which serves as a channel for publishing and consuming event data. Topics allow you to organize and categorize your data streams effectively. You can also think of a topic as a table that will be used to store specific events within a database. You can create a topic using Kafka's command-line tools or administrative interfaces like Kafka Manager.

In Apache Kafka, topics are divided into multiple partitions, with each partition being managed by a specific broker. These brokers are responsible for various aspects of partition management, including overseeing the leader and follower replicas for each partition. When setting up your Kafka cluster, you'll need to specify the number of partitions, which determines how the cluster handles scalability and distribution of data.

The next step to integrating Apache Kafka into your JavaScript website is to install the Kafka JavaScript client, which is available via npm. The Kafka JavaScript client provides a simple and easy-to-use API for interacting with Apache Kafka from your JavaScript code.

To interact with Kafka from your JavaScript website, you'll need to choose a suitable Kafka client library. There are several options available, but two popular choices are kafka-node and node-rdkafka. These client libraries provide the necessary functionalities for producing and consuming messages from Kafka topics.

Installing the Kafka JavaScript Client

To install the Kafka JavaScript client, simply run the following command in your project directory:

npm install kafka-node --save

This will install the Kafka JavaScript client and add it as a dependency to your project.

You will need to configure the connection to your Kafka cluster by specifying the broker addresses and topic details. Refer to the documentation of the chosen library as well as Kafka provider for specific configuration instructions.

Once the installation is complete, you can start using the Kafka client in your code. You can import the Kafka client using the following code:

const kafka = require('kafka-node');

Configuring the Kafka Producer and Consumer

Before we can start sending data to Kafka, we'll need to configure our producer and consumer. The producer is responsible for writing data to the Kafka cluster, while the consumer reads that data and processes it. In our case, we'll be using a simple implementation where the producer and consumer are both hosted on the same server.

To configure our Kafka producer, we'll need to create a new instance of the kafka.Producer class, passing in the appropriate configuration details. This will typically include the IP address and port of the Kafka cluster, as well as any authentication credentials if necessary. The producer can then be used to send messages to the Kafka cluster using the send() method:

const kafka = require('kafka-node');
const Producer = kafka.Producer;
const client = new kafka.KafkaClient({ kafkaHost: localhost:9092});
const producer = new Producer(client);
const topic = 'your-topic-name';
producer.on('ready', () => {
const message = { key: 'your-key', value: 'your-value' };
const payloads = [{ topic: topic, messages: [JSON.stringify(message)] }];
producer.send(payloads, (error, data) => {
if (error) {
console.error('Error sending message to Kafka:', error);
} else {
console.log('Message sent to Kafka:', data);
producer.on('error', (error) => {
console.error('Error connecting to Kafka:', error);

Make sure to replace 'your-topic-name', 'your-key', and 'your-value' with the appropriate values for your scenario.

Next step would be consuming event data from the broker. In Apache Kafka, consumers are applications or components that read and process data from Kafka topics. They allow you to consume and react to the messages published to Kafka in real-time.

Consumers may exist within consumer groups. Each consumer within a group is assigned to consume from a subset of partitions within the topics it subscribes to. The partitions are distributed across the consumers in a balanced manner. This parallelism allows for high throughput and fault tolerance.

Similarly, to configure our Kafka consumer, we'll need to create a new instance of the kafka.Consumer class, again passing in the appropriate configuration details. We'll also need to specify the topics that the consumer should be listening to, which is the same topic that our producer will be writing to. The consumer can then be used to read messages from the Kafka cluster using the on() method.

const kafka = require('kafka-node');
const Consumer = kafka.Consumer;
const client = new kafka.KafkaClient({ kafkaHost: localhost:9092 });
const topic = 'your-topic-name';
const consumer = new Consumer(client, [{ topic: topic, partition: 0 }], { autoCommit: false });
consumer.on('message', (message) => {
console.log('Received message:', message.value);
// Perform your desired operations with the received message here
consumer.on('error', (error) => {
console.error('Error occurred while consuming:', error);
process.on('SIGINT', () => {
consumer.close(true, () => {
console.log('Kafka consumer closed.');

By using Apache Kafka in your JavaScript website, you can easily handle real-time data feeds and messaging between your website and other systems. With the Kafka JavaScript client, it's easy to configure and use both producers and consumers, allowing you to easily send and receive messages between the Kafka cluster and your web app.


In this article, we've explored the steps involved in sending data from your JavaScript website to Apache Kafka. We've covered topics such as understanding Apache Kafka and its role in data streaming, setting up your JavaScript website, integrating Apache Kafka into your code, and sending and consuming data from Kafka. By following these steps, you should be able to effectively send and receive data in real-time with the help of Apache Kafka. Check out RudderStack's Javascript website to Apache Kafka integration.

Don't want to go through the pain of direct integration? RudderStack's JavaScript SDK makes it easy to send data from your JavaScript website to Apache Kafka .