Replay vs Builder.io: Which Generates the Most Scalable Code from Video in 2026?

TL;DR: Replay leverages video analysis and behavior-driven reconstruction to generate more scalable and maintainable code compared to Builder.io's screenshot-based approach, especially for complex, multi-page applications.

The promise of AI-powered code generation is alluring: turn ideas into working software faster than ever before. But most tools stumble when faced with real-world complexity. Screenshot-to-code solutions, like those offered by Builder.io, often fall short because they lack a deep understanding of user intent and application flow. They see what the user interface looks like, but not how the user interacts with it. This is where Replay shines.

Replay: Understanding Behavior, Not Just Pixels#

Replay uses video analysis to reconstruct working UI from screen recordings. This "Behavior-Driven Reconstruction" approach, powered by Gemini, allows Replay to go beyond simple visual replication. It understands the why behind user actions, enabling the generation of code that is not only visually accurate but also functionally robust and easily scalable.

Why Video Matters: Context is King#

The critical difference between Replay and other solutions like Builder.io lies in the input. While Builder.io relies on static screenshots, Replay analyzes video. This provides a wealth of contextual information:

• •User Flows: Replay tracks user navigation, button clicks, form submissions, and other interactions, allowing it to understand the intended application flow.
• •Dynamic Behavior: Video captures animations, transitions, and other dynamic UI elements that are impossible to represent in a static screenshot.
• •Data Dependencies: By observing how data changes during user interactions, Replay can infer data dependencies and generate code that correctly handles data fetching and manipulation.

Replay vs. Builder.io: A Head-to-Head Comparison#

Let's examine a direct comparison of Replay and Builder.io across key code generation features:

As the table illustrates, Replay offers a significant advantage in understanding user intent and generating scalable code, particularly for complex applications.

Building a Multi-Page Application: A Practical Example#

Imagine you want to rebuild a simple e-commerce application from a screen recording of a user browsing and purchasing a product. Let's explore how Replay handles this scenario, compared to a screenshot-based approach.

Step 1: Recording the User Flow#

First, record a video of a user navigating through the e-commerce application:

1. •Browsing the product catalog
2. •Selecting a product
3. •Adding the product to the cart
4. •Proceeding to checkout
5. •Entering shipping and payment information
6. •Completing the purchase

Step 2: Generating Code with Replay#

Upload the video to Replay. Replay's AI engine analyzes the video, identifies the different pages and components, and reconstructs the application's logic.

typescript
// Example Replay-generated component for the product details page
import React, { useState, useEffect } from 'react';
import { useParams } from 'react-router-dom';

const ProductDetails = () => {
  const { productId } = useParams();
  const [product, setProduct] = useState(null);

  useEffect(() => {
    const fetchProduct = async () => {
      const response = await fetch(`/api/products/${productId}`);
      const data = await response.json();
      setProduct(data);
    };

    fetchProduct();
  }, [productId]);

  if (!product) {
    return <div>Loading...</div>;
  }

  return (
    <div>
      <h1>{product.name}</h1>
      <img src={product.image} alt={product.name} />
      <p>{product.description}</p>
      <p>Price: ${product.price}</p>
      <button onClick={() => alert('Added to cart!')}>Add to Cart</button>
    </div>
  );
};

export default ProductDetails;

💡 Pro Tip: Replay automatically infers the API endpoint (

text

/api/products/${productId}

) and generates the necessary

text

useEffect

hook to fetch the product data.

Step 3: Style Injection and Customization#

Replay allows you to inject custom styles to match your design system. You can use CSS-in-JS libraries like Styled Components or Emotion to style the generated components.

javascript
// Example using Styled Components
import styled from 'styled-components';

const ProductDetailsContainer = styled.div`
  padding: 20px;
  border: 1px solid #ccc;
  border-radius: 5px;
`;

const ProductName = styled.h1`
  font-size: 24px;
  margin-bottom: 10px;
`;

// Use these styled components in your React component

📝 Note: Replay can also analyze existing style guides and automatically apply them to the generated code, ensuring consistency across your application.

Step 4: Supabase Integration#

Replay seamlessly integrates with Supabase, allowing you to quickly connect your generated application to a backend database. Replay can infer the necessary database schema and generate the code for data fetching and manipulation.

typescript
// Example of Supabase integration for fetching product data
import { createClient } from '@supabase/supabase-js';

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

const fetchProductFromSupabase = 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;
};

⚠️ Warning: Remember to replace

text

YOUR_SUPABASE_URL

and

text

YOUR_SUPABASE_ANON_KEY

with your actual Supabase credentials.

The Scalability Advantage#

The key difference between Replay and Builder.io in this scenario becomes apparent when considering scalability. A screenshot-based approach would likely generate static HTML or simple React components that require significant manual modification to handle dynamic data, state management, and complex user interactions.

Replay, on the other hand, generates code that is inherently more scalable because it understands the underlying application logic. It infers data dependencies, manages state, and handles user interactions in a way that is consistent and maintainable.

Beyond Code: Product Flow Maps#

Replay goes beyond simple code generation by providing visual product flow maps. These maps are automatically generated from the video analysis and provide a clear overview of the user's journey through the application. This can be invaluable for understanding user behavior, identifying potential bottlenecks, and optimizing the user experience.

Replay's Key Advantages:#

• •Behavior-Driven Reconstruction: Understands user intent, not just visual representation.
• •Multi-Page Generation: Handles complex, multi-page applications with ease.
• •Supabase Integration: Seamlessly connects to a powerful backend database.
• •Style Injection: Supports CSS-in-JS and theming for consistent styling.
• •Product Flow Maps: Provides visual insights into user behavior.

In contrast, Builder.io, while powerful for page building and visual editing, struggles with the dynamic and behavioral aspects of complex applications. Its screenshot-based approach limits its ability to understand user intent and generate truly scalable code.

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 Replay and v0.dev aim to generate code from AI, they differ significantly in their approach. v0.dev primarily focuses on generating UI components from text prompts, while Replay focuses on reconstructing entire applications from video recordings, with a strong emphasis on understanding user behavior and application flow. Replay's video-first approach allows it to capture nuances and context that are impossible to convey in a text prompt.

What frameworks does Replay support?#

Replay currently supports React and Next.js, with plans to add support for other popular frameworks in the future.

Can I use Replay to generate code for mobile applications?#

Yes, Replay can be used to generate code for mobile applications, as long as you have a screen recording of the user interacting with the mobile app.

How accurate is the code generated by Replay?#

The accuracy of the generated code depends on the quality of the video recording and the complexity of the application. However, Replay's Behavior-Driven Reconstruction approach ensures that the generated code is not only visually accurate but also functionally robust and maintainable.

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