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Are Real-Time Updates Possible with HTML-over-the-Wire?


In recent years, HTML-over-the-Wire has gained traction as a powerful and efficient approach to building web applications. By relying on server-side rendering (SSR) and delivering HTML fragments over the wire, this technique minimizes client-side processing and simplifies the development process. One question that often arises is whether real-time updates – a critical feature in modern web applications – are possible with HTML-over-the-Wire. In this article, we will explore the feasibility of implementing real-time updates using HTML-over-the-Wire and discuss various techniques and tools to achieve this goal.

Real-Time Updates in Web Applications

What are Real-Time Updates?

Real-time updates refer to the ability of a web application to instantly display new or updated information without requiring a full page refresh or any user interaction. Some common examples of real-time updates include chat applications, notifications, stock tickers, and live sports scores. These updates are essential for providing users with a seamless and engaging experience, and they have become a standard expectation in modern web applications.

Traditional Approaches

Historically, developers have used various methods to implement real-time updates in web applications. Two of the most common approaches are AJAX polling and long-polling, which involve periodically sending requests to the server to check for new information. While these methods can achieve real-time updates, they may result in unnecessary server load and latency due to the frequent requests.

A more efficient alternative is using WebSockets and Server-Sent Events (SSE). WebSockets provide a full-duplex communication channel between the client and server, allowing for low-latency, real-time communication. Similarly, SSE enables servers to push updates to the client over a single, long-lived connection. These approaches have become popular for implementing real-time updates due to their performance benefits and compatibility with modern web standards.

HTML-over-the-Wire and Real-Time Updates

Server-Side Rendering and Partial Updates

At the core of HTML-over-the-Wire is server-side rendering, which involves generating the HTML content on the server and sending it to the client. This approach can be leveraged to deliver real-time updates by sending partial updates (i.e., updated HTML fragments) to the client, which are then integrated into the existing DOM.

By only updating the relevant parts of the page, developers can minimize the amount of data transferred and client-side processing, resulting in a more efficient and responsive user experience. However, achieving real-time updates with this approach requires careful consideration of how the server-side rendering and partial updates are implemented.

Leveraging WebSockets and SSE

To achieve real-time updates with HTML-over-the-Wire, developers can combine server-side rendering with WebSockets or SSE. By establishing a persistent connection between the client and server, these technologies enable low-latency, real-time communication, making them an ideal choice for delivering server-generated HTML fragments.

In this setup, the server can push updated HTML fragments to the client whenever new information becomes available, allowing the application to display real-time updates without relying on AJAX polling or long-polling. This approach not only provides a seamless user experience but also reduces the server load and bandwidth consumption associated with traditional methods.

Real-World Examples

Phoenix LiveView

Phoenix LiveView is an innovative library built on top of the Elixir programming language and the Phoenix web framework. It brings the capabilities of HTML-over-the-Wire to life by enabling developers to build real-time applications with server-rendered HTML. One of the key features of Phoenix LiveView is its support for real-time updates through efficient server-side rendering and WebSockets.

Using Phoenix LiveView, developers can create live components that automatically update in response to server-side changes. By leveraging Elixir's lightweight processes and the WebSocket communication, LiveView efficiently manages real-time updates, minimizing server load and latency. This approach allows developers to build highly interactive applications without needing to write complex JavaScript code or manage client-side state.

Hotwire's Turbo Streams

Hotwire is an open-source framework developed by the creators of Ruby on Rails that aims to simplify modern web development. One of its core components, Turbo Streams, enables real-time updates through HTML-over-the-Wire using server-generated HTML fragments and WebSocket connections.

Turbo Streams allows developers to push server-rendered updates to the client over a WebSocket connection. These updates can target specific parts of the page, making it easy to implement real-time updates without requiring a full page refresh or complex client-side logic. By combining the simplicity of server-side rendering with the low-latency communication of WebSockets, Turbo Streams offers a powerful solution for building real-time applications using HTML-over-the-Wire.

Challenges and Considerations

Performance and Scalability

While HTML-over-the-Wire provides a straightforward approach to implementing real-time updates, developers must carefully consider performance and scalability. Ensuring efficient server-side rendering and partial updates is crucial for maintaining a responsive user experience, especially in applications with a high volume of real-time updates.

To optimize performance, developers should minimize the amount of data transferred in each update and ensure that server-side rendering is as fast as possible. Additionally, leveraging tools and techniques specific to each framework (such as Elixir's lightweight processes in Phoenix LiveView) can help optimize performance and scalability.

Fallback Strategies

In some cases, real-time updates may fail or be unsupported due to factors such as network issues or browser compatibility. To ensure a consistent user experience, developers should implement fallback strategies that gracefully degrade the application's functionality in these situations.

One common approach is to leverage progressive enhancement, in which the application is built with a baseline of functionality that works without real-time updates, and then enhanced with real-time capabilities when supported. This ensures that users can still interact with the application even if real-time updates are unavailable, while still providing an optimal experience for those with support for real-time updates.

HTMX with WebSockets and SSE

HTMX is a lightweight library for building modern web applications using HTML-over-the-Wire. It allows developers to create highly interactive applications by enhancing static HTML with attributes that define AJAX-like behavior. While HTMX does not natively support WebSockets or SSE, it can be extended to work with these technologies, enabling real-time updates in HTMX-based projects.

To integrate HTMX with WebSockets or SSE, developers can use event listeners to establish connections and listen for incoming messages. When a message containing an updated HTML fragment is received, the HTMX htmx.process() function can be used to update the DOM. This approach allows developers to achieve real-time updates in HTMX-based applications while leveraging the benefits of WebSockets or SSE for efficient communication.

Here's an example of how to integrate HTMX with WebSockets:

document.addEventListener('DOMContentLoaded', function () {
  const websocket = new WebSocket('ws://');

  websocket.onmessage = function (event) {
    const fragment = document.createElement('template');
    fragment.innerHTML =;

    // Update the DOM with the received HTML fragment

Similarly, SSE can be integrated with HTMX as follows:

document.addEventListener('DOMContentLoaded', function () {
  const source = new EventSource('/event-source-url');

  source.onmessage = function (event) {
    const fragment = document.createElement('template');
    fragment.innerHTML =;

    // Update the DOM with the received HTML fragment


Implementing real-time updates with HTML-over-the-Wire is not only possible but can be achieved with various tools and techniques, such as Phoenix LiveView, Hotwire's Turbo Streams, and HTMX combined with WebSockets or SSE. By leveraging server-side rendering and partial updates, developers can create efficient and responsive web applications that meet the demands of today's users.

As web development continues to evolve, HTML-over-the-Wire offers a compelling alternative to traditional client-side heavy approaches. We encourage developers to explore and leverage the capabilities of HTML-over-the-Wire for real-time updates, creating web applications that deliver a seamless and engaging user experience.

Frequently Asked Questions

1. Is HTML-over-the-Wire suitable for all types of applications?

While HTML-over-the-Wire is a versatile approach, its suitability depends on the specific requirements and constraints of your application. For applications that require extensive client-side functionality or complex state management, a traditional client-side framework might be more suitable. However, for many web applications, HTML-over-the-Wire can provide a simpler and more efficient alternative.

2. Can I use HTML-over-the-Wire alongside a client-side framework like React or Vue?

Yes, it is possible to use HTML-over-the-Wire alongside a client-side framework. This hybrid approach allows you to leverage the benefits of both server-side rendering and client-side interactivity. However, it's essential to carefully plan and architect the application to avoid unnecessary complexity or duplication of functionality.

3. How does HTML-over-the-Wire compare to other real-time technologies like WebSockets and SSE?

HTML-over-the-Wire complements real-time technologies like WebSockets and SSE by providing a means to deliver server-rendered HTML fragments over these connections. This allows developers to implement real-time updates with minimal client-side processing and a simpler development workflow.

4. Is HTML-over-the-Wire compatible with all browsers?

HTML-over-the-Wire relies on modern web standards and is generally compatible with the latest versions of all major browsers. However, developers should test their applications across different browsers and implement fallback strategies as needed to ensure a consistent user experience.

5. Can I implement real-time updates with HTML-over-the-Wire without using a specific framework or library?

While using a dedicated framework or library like Phoenix LiveView, Hotwire, or HTMX can simplify the process, it is possible to implement real-time updates using HTML-over-the-Wire without these tools. By combining server-side rendering with WebSockets or SSE, developers can create custom solutions tailored to their application's specific needs.

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