Replay vs Builder.io (2026): Which AI Code Generator is Best for E-commerce Sites?

TL;DR: Replay leverages behavior-driven reconstruction from video to generate functional e-commerce UI, surpassing Builder.io's component-based approach by understanding user intent and creating complete product flows.

Replay vs Builder.io (2026): Which AI Code Generator is Best for E-commerce Sites?#

The landscape of AI-powered code generation is rapidly evolving. In 2026, the question isn't just can AI generate code, but how well can it understand user needs and translate them into functional, maintainable applications. For e-commerce sites, the stakes are especially high – a seamless user experience directly impacts conversion rates. Two prominent players in this space are Replay and Builder.io, but they approach the problem from drastically different angles.

Builder.io focuses on a component-based, drag-and-drop approach with AI assistance. Replay, on the other hand, pioneers a "Behavior-Driven Reconstruction" method that leverages video analysis to understand user intent and generate complete, working UI directly from screen recordings. Let's dive into the specifics.

Understanding the Core Differences#

The fundamental difference lies in the source of truth. Builder.io relies on pre-built components and visual design inputs, while Replay uses video recordings of user interactions as its primary data source. This distinction has profound implications for the type of applications each tool is best suited for.

The Power of Behavior-Driven Reconstruction#

Replay's core strength lies in its ability to analyze video recordings to understand what users are trying to achieve, not just what they see. This "Behavior-Driven Reconstruction" approach allows Replay to generate more than just static UI elements; it reconstructs the entire user flow, including state management, API calls, and event handling.

💡 Pro Tip: Think of Replay as an AI developer observing a user interacting with your (or your competitor's) e-commerce site and then automatically building a similar experience from scratch.

Consider a user adding an item to their cart on an e-commerce site. Replay captures this interaction, analyzes the video, and understands the following:

1. •The user clicked on a specific product.
2. •The user selected a size and color.
3. •The user clicked the "Add to Cart" button.
4. •The cart quantity was updated.

Replay then generates the necessary code to replicate this entire flow, including the UI elements, event handlers, and API calls to update the cart in the backend.

Implementing Replay in Your E-commerce Workflow#

Here's a practical example of how you can use Replay to reconstruct a product page from a video recording:

Step 1: Capture the Video#

Record a video of a user interacting with a product page on your existing e-commerce site (or a competitor's site for inspiration). Make sure the video clearly shows all the user interactions, including scrolling, clicking, and typing.

Step 2: Upload to Replay#

Upload the video to the Replay platform. Replay will automatically analyze the video and begin reconstructing the UI.

Step 3: Review and Refine the Generated Code#

Replay will generate a fully functional product page, complete with UI elements, event handlers, and backend integration. Review the generated code and make any necessary adjustments to match your specific requirements.

Here's an example of the generated code (simplified for brevity):

typescript
// Generated by Replay
import React, { useState, useEffect } from 'react';

const ProductPage = () => {
  const [product, setProduct] = useState({});
  const [quantity, setQuantity] = useState(1);

  useEffect(() => {
    // Fetch product data from API
    const fetchProduct = async () => {
      const response = await fetch('/api/products/123');
      const data = await response.json();
      setProduct(data);
    };

    fetchProduct();
  }, []);

  const handleAddToCart = async () => {
    // Add product to cart via API
    await fetch('/api/cart', {
      method: 'POST',
      body: JSON.stringify({
        productId: product.id,
        quantity: quantity,
      }),
    });
    alert('Product added to cart!');
  };

  return (
    <div>
      <h1>{product.name}</h1>
      <p>{product.description}</p>
      <input
        type="number"
        value={quantity}
        onChange={(e) => setQuantity(parseInt(e.target.value))}
      />
      <button onClick={handleAddToCart}>Add to Cart</button>
    </div>
  );
};

export default ProductPage;

📝 Note: This is a simplified example. Replay generates much more complex code, including styling, responsive layouts, and error handling.

Builder.io: Component-Based Creation#

Builder.io excels at building content-rich pages and landing pages. Its visual editor allows users to drag and drop pre-built components and customize their appearance and behavior. AI assistance can help with content generation and suggesting relevant components. However, Builder.io's component-based approach can be limiting when it comes to building complex, interactive e-commerce flows. It lacks the nuanced understanding of user intent that Replay provides.

Feature Comparison: Deep Dive#

Let's compare some key features in more detail:

When to Choose Replay#

Replay is the ideal choice for e-commerce sites that require:

• •Complex product flows, such as multi-step checkout processes or personalized product recommendations.
• •Deep integration with backend systems, such as inventory management and order processing.
• •A focus on user experience and conversion optimization.
• •Rapid prototyping and iteration based on real-world user behavior.

Addressing Potential Concerns#

⚠️ Warning: Replay's reliance on video analysis means that the quality of the generated code is directly dependent on the quality of the video recording. Make sure to capture clear, high-resolution videos that accurately reflect user interactions.

Some might argue that Replay's output requires more developer oversight compared to Builder.io's visual approach. While code review is crucial, the time saved by automating the initial UI reconstruction and backend integration far outweighs the effort required for manual coding. Replay generates a solid foundation, allowing developers to focus on fine-tuning and optimization.

Code Example: Supabase Integration#

Replay offers seamless integration with Supabase, allowing you to easily connect your generated UI to a scalable and secure backend. Here's an example of how Replay can automatically generate code to fetch product data from a Supabase database:

typescript
// Generated by Replay
import { createClient } from '@supabase/supabase-js';

const supabaseUrl = 'YOUR_SUPABASE_URL';
const supabaseKey = 'YOUR_SUPABASE_ANON_KEY';
const supabase = createClient(supabaseUrl, supabaseKey);

const fetchProduct = async (productId: string) => {
  const { data, error } = await supabase
    .from('products')
    .select('*')
    .eq('id', productId)
    .single();

  if (error) {
    console.error('Error fetching product:', error);
    return null;
  }

  return data;
};

export default fetchProduct;

This code snippet demonstrates how Replay automatically generates the necessary Supabase client and query to fetch product data based on the user's interaction in the video recording.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features and usage. Paid plans are available for more advanced features and higher usage limits. Check the Replay pricing page for details.

How is Replay different from v0.dev?#

While both tools aim to generate code from prompts, Replay uniquely uses video as the primary input. v0.dev relies on text prompts and pre-existing code snippets, limiting its ability to understand complex user flows and generate complete applications. Replay's behavior-driven approach provides a more comprehensive and accurate reconstruction of the desired UI.

Can Replay handle dynamic content?#

Yes, Replay can handle dynamic content by analyzing the video recording to identify the data sources and API calls required to populate the UI with real-time information. It can then generate the necessary code to fetch and display the dynamic content.

What frameworks and libraries does Replay support?#

Replay supports a wide range of popular frameworks and libraries, including React, Vue.js, Angular, and Next.js. The generated code is clean, well-structured, and easy to integrate into existing projects.

---

Ready to try behavior-driven code generation? Get started with Replay - transform any video into working code in seconds.