Replay vs. Lovable.dev: Building Clean UI Code With Proper Component Structure? (2026)

TL;DR: Replay leverages video analysis and behavior-driven reconstruction to generate clean, component-based UI code, offering a significant advantage over screenshot-to-code tools like Lovable.dev, particularly in understanding user intent and complex multi-page flows.

The promise of AI-powered UI generation has arrived, but the devil is in the details. While tools like Lovable.dev can generate code from screenshots, they often fall short when it comes to understanding user intent and creating maintainable, component-based code. This is where Replay steps in, offering a fundamentally different approach based on video analysis and "Behavior-Driven Reconstruction."

Understanding the Problem: Beyond Screenshots#

Screenshot-to-code tools are limited by their input: static images. They can translate visual elements into code, but they lack the context of how a user interacts with the interface. This leads to:

• •Poor Component Structure: Code often lacks proper componentization, making it difficult to maintain and reuse.
• •Missing Logic: Interactions, animations, and state management are often ignored, requiring significant manual implementation.
• •Multi-Page Blindness: Generating code for multi-page flows is a challenge, as the tool only sees one screen at a time.

Replay addresses these limitations by analyzing video recordings of user interactions. This allows it to understand the behavior behind the UI, not just its appearance.

Replay: Behavior-Driven Reconstruction in Action#

Replay uses a video as the source of truth, employing AI (powered by Gemini) to reconstruct a working UI. This "Behavior-Driven Reconstruction" approach offers several key advantages:

• •Video as Input: Analyzes video recordings of user interactions, capturing the full context of user behavior.
• •Multi-Page Generation: Can generate code for entire product flows, not just individual screens.
• •Supabase Integration: Seamlessly integrates with Supabase for backend functionality.
• •Style Injection: Allows for easy customization and branding.
• •Product Flow Maps: Visualizes user flows, providing a clear understanding of the application's logic.

A Concrete Example: Building a Simple Task List#

Let's say you want to build a simple task list application. With Lovable.dev, you would need to provide screenshots of each state (empty list, list with items, editing an item, etc.). Replay, on the other hand, only needs a video recording of you interacting with a similar task list application.

Here's a simplified example of the code Replay might generate (using React and TypeScript):

typescript
// TaskItem.tsx
import React, { useState } from 'react';

interface TaskItemProps {
  task: { id: number; text: string; completed: boolean };
  onUpdate: (id: number, updatedTask: { text: string; completed: boolean }) => void;
  onDelete: (id: number) => void;
}

const TaskItem: React.FC<TaskItemProps> = ({ task, onUpdate, onDelete }) => {
  const [isEditing, setIsEditing] = useState(false);
  const [editText, setEditText] = useState(task.text);

  const handleUpdate = () => {
    onUpdate(task.id, { text: editText, completed: task.completed });
    setIsEditing(false);
  };

  return (
    <li>
      {isEditing ? (
        <>
          <input
            type="text"
            value={editText}
            onChange={(e) => setEditText(e.target.value)}
          />
          <button onClick={handleUpdate}>Save</button>
          <button onClick={() => setIsEditing(false)}>Cancel</button>
        </>
      ) : (
        <>
          <input
            type="checkbox"
            checked={task.completed}
            onChange={(e) => onUpdate(task.id, { ...task, completed: e.target.checked })}
          />
          <span style={{ textDecoration: task.completed ? 'line-through' : 'none' }}>
            {task.text}
          </span>
          <button onClick={() => setIsEditing(true)}>Edit</button>
          <button onClick={() => onDelete(task.id)}>Delete</button>
        </>
      )}
    </li>
  );
};

export default TaskItem;

//TaskList.tsx
import React, { useState } from 'react';
import TaskItem from './TaskItem';

interface Task {
  id: number;
  text: string;
  completed: boolean;
}

const TaskList: React.FC = () => {
  const [tasks, setTasks] = useState<Task[]>([
    { id: 1, text: 'Learn Replay', completed: false },
    { id: 2, text: 'Build a Task List', completed: true },
  ]);
  const [newTaskText, setNewTaskText] = useState('');

  const handleAddTask = () => {
    if (newTaskText.trim() !== '') {
      setTasks([...tasks, { id: Date.now(), text: newTaskText, completed: false }]);
      setNewTaskText('');
    }
  };

  const handleUpdateTask = (id: number, updatedTask: { text: string; completed: boolean }) => {
    setTasks(tasks.map((task) => (task.id === id ? { ...task, ...updatedTask } : task)));
  };

  const handleDeleteTask = (id: number) => {
    setTasks(tasks.filter((task) => task.id !== id));
  };


  return (
    <div>
      <h1>Task List</h1>
      <input
        type="text"
        placeholder="Add new task"
        value={newTaskText}
        onChange={(e) => setNewTaskText(e.target.value)}
      />
      <button onClick={handleAddTask}>Add Task</button>
      <ul>
        {tasks.map((task) => (
          <TaskItem
            key={task.id}
            task={task}
            onUpdate={handleUpdateTask}
            onDelete={handleDeleteTask}
          />
        ))}
      </ul>
    </div>
  );
};

export default TaskList;

This code demonstrates how Replay can generate a functional task list with proper component structure, including state management and event handling, based on a video of user interaction. Lovable.dev, based on screenshots, would likely generate a static representation of the UI, lacking the interactive elements.

Replay vs. Lovable.dev: A Detailed Comparison#

The following table highlights the key differences between Replay and Lovable.dev:

💡 Pro Tip: When recording your video for Replay, focus on clearly demonstrating the different states and interactions of your UI. This will help Replay generate more accurate and complete code.

Addressing Common Concerns#

One common concern is the accuracy and reliability of AI-generated code. While no tool is perfect, Replay's behavior-driven approach significantly reduces the risk of errors. By analyzing video, it can understand the intended behavior and generate code that accurately reflects that behavior.

⚠️ Warning: Always review the generated code carefully and test it thoroughly. AI-generated code is a great starting point, but it may still require manual adjustments and refinements.

Another concern is the learning curve. While Replay is designed to be user-friendly, understanding the principles of behavior-driven reconstruction can help you get the most out of the tool.

Step-by-Step Guide: Using Replay to Generate UI Code#

Here's a simplified guide to using Replay:

Step 1: Record a Video#

Record a video of yourself interacting with a UI that is similar to the one you want to generate. Be sure to demonstrate all the key states and interactions.

Step 2: Upload the Video to Replay#

Upload the video to the Replay platform.

Step 3: Review and Customize#

Review the generated code and make any necessary adjustments. Use the style injection feature to customize the appearance of the UI.

Step 4: Integrate with Your Project#

Integrate the generated code into your project.

📝 Note: Replay is constantly evolving, with new features and improvements being added regularly. Be sure to check the documentation for the latest information.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features. Paid plans are available for more advanced functionality.

How is Replay different from v0.dev?#

While both tools aim to generate UI code, Replay uses video analysis to understand user behavior, while v0.dev primarily relies on text prompts. Replay's approach allows for more accurate and complete code generation, particularly for complex interactions and multi-page flows.

What frameworks and libraries does Replay support?#

Replay currently supports React, Vue, and Angular. Support for other frameworks is planned for the future.

How secure is Replay?#

Replay uses industry-standard security measures to protect your data. All video recordings are stored securely and encrypted.

Conclusion: The Future of UI Generation#

Replay represents a significant step forward in the field of AI-powered UI generation. By focusing on behavior and understanding user intent, it offers a more accurate, efficient, and maintainable solution than traditional screenshot-to-code tools. While tools like Lovable.dev have their place, Replay's video-driven approach is poised to become the new standard for building clean, component-based UI code.

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