Replay vs Builder.io: Which is faster for generating CRUD apps from video input for complex apps

TL;DR: Replay generates working CRUD apps from video recordings faster and with more functional fidelity than Builder.io, especially for complex applications requiring multi-page workflows and data integration.

The promise of AI-powered code generation is tantalizing: turn ideas into working software in minutes. But when you're dealing with complex applications, the devil is in the details. Can these tools truly handle the nuances of user behavior and data interactions? We put Replay and Builder.io head-to-head, focusing on the speed and accuracy of generating CRUD (Create, Read, Update, Delete) applications from video input.

The Challenge: Building a Multi-Page Task Management App#

We tasked both Replay and Builder.io with generating a basic task management application. The input? A 2-minute video recording demonstrating the creation, editing, and deletion of tasks across multiple pages, including integration with a mock Supabase backend. This wasn't just about generating static layouts; we needed functional components, data binding, and working API calls.

Round 1: Setup and Input#

Builder.io#

Builder.io primarily focuses on visual editing and content management. While it offers AI-powered code generation, it's more geared towards converting designs or screenshots into code. Using video as a direct input isn't its primary strength. We had to manually extract key screens from the video and feed them into Builder.io's AI assistant.

Replay#

Replay, on the other hand, is built from the ground up to analyze video recordings. It uses "Behavior-Driven Reconstruction," meaning it analyzes user interactions within the video to understand the intent behind the actions.

Step 1: Uploading the Video to Replay#

1. •Sign up for a Replay account at https://replay.build.
2. •Create a new project and upload the 2-minute task management app video.
3. •Replay automatically processes the video, identifying key UI elements, user interactions, and page transitions.

💡 Pro Tip: Ensure your video is clear and well-lit for optimal analysis by Replay. Speak clearly while demonstrating the workflow.

Round 2: Code Generation and Functionality#

Builder.io#

Builder.io generated a basic layout based on the screenshots we provided. However, the functionality was limited. Data binding to the mock Supabase backend required significant manual coding. Multi-page navigation also needed custom implementation.

Replay#

Replay generated a fully functional multi-page application, including:

• •Working CRUD operations for tasks.
• •Data binding to the mock Supabase backend (configured during setup).
• •Navigation between pages.
• •Basic styling that mirrored the video recording.

Step 2: Integrating Supabase with Replay#

Replay simplifies backend integration with Supabase. Here's how:

1. •In your Replay project, navigate to the "Integrations" tab.
2. •Enter your Supabase URL and API key.
3. •Replay automatically infers the database schema from your Supabase project.
4. •Specify the table name for your tasks (e.g., "tasks").

Step 3: Reviewing and Customizing the Generated Code#

Replay generates clean, readable code that you can easily customize. Here's an example of a generated React component for creating a new task:

typescript
// Replay generated code for creating a new task
import { useState } from 'react';
import { supabase } from './supabaseClient'; // Assuming you have a supabaseClient.js

const CreateTask = () => {
  const [title, setTitle] = useState('');
  const [description, setDescription] = useState('');

  const handleSubmit = async (e) => {
    e.preventDefault();

    try {
      const { data, error } = await supabase
        .from('tasks')
        .insert([{ title, description }]);

      if (error) {
        console.error('Error creating task:', error);
      } else {
        console.log('Task created successfully:', data);
        // Reset the form
        setTitle('');
        setDescription('');
      }
    } catch (error) {
      console.error('An unexpected error occurred:', error);
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="title">Title:</label>
        <input
          type="text"
          id="title"
          value={title}
          onChange={(e) => setTitle(e.target.value)}
        />
      </div>
      <div>
        <label htmlFor="description">Description:</label>
        <textarea
          id="description"
          value={description}
          onChange={(e) => setDescription(e.target.value)}
        />
      </div>
      <button type="submit">Create Task</button>
    </form>
  );
};

export default CreateTask;

📝 Note: This is a simplified example. Replay also generates code for updating and deleting tasks, as well as handling error states.

Round 3: Speed and Accuracy#

Replay significantly outperformed Builder.io in terms of both speed and accuracy. It took us several hours to get a partially functional app with Builder.io, requiring extensive manual coding. Replay generated a fully functional application in under 30 minutes, with minimal customization needed.

⚠️ Warning: While Replay significantly reduces development time, it's not a magic bullet. You'll still need to review and customize the generated code to meet your specific requirements.

Why Replay Wins for Complex Apps#

Replay's "Behavior-Driven Reconstruction" is the key differentiator. It doesn't just generate code based on static screenshots; it understands the flow of the application, the user's intent, and the relationships between different UI elements. This allows it to generate more functional and complete code, especially for complex applications with multi-page workflows and data interactions.

Here's a breakdown of Replay's key advantages:

• •Video as Source of Truth: Eliminates the need for manual design specifications or mockups.
• •Behavior-Driven Reconstruction: Understands user intent and generates functional code accordingly.
• •Multi-Page Generation: Automatically handles navigation and data flow between pages.
• •Supabase Integration: Simplifies backend integration and data binding.
• •Style Injection: Captures the visual style from the video and applies it to the generated code.
• •Product Flow Maps: Replay can also generate visual diagrams of the user flow, useful for documentation and collaboration.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features. Paid plans are available for more advanced features and higher usage limits. Check https://replay.build for current pricing.

How is Replay different from v0.dev?#

While both tools aim to generate code, Replay focuses on video input and behavior-driven reconstruction. v0.dev relies on text prompts and generates code based on pre-defined templates. Replay is better suited for capturing existing workflows and translating them into working code.

What kind of applications can I build with Replay?#

Replay is ideal for building CRUD applications, internal tools, dashboards, and other applications with complex user flows. Any application that can be demonstrated in a video can be reconstructed with Replay.

What frameworks does Replay support?#

Currently, Replay primarily generates React code. Support for other frameworks is planned for future releases.

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