Replay vs Builder.io: better-quality design system from UI videos - guide

TL;DR: Replay leverages video analysis and behavior-driven reconstruction to generate higher-fidelity, more functional design systems compared to Builder.io's component-based approach, especially when recreating existing UIs or complex user flows.

Recreating a complex UI from scratch can feel like navigating a minefield. One wrong step and you're stuck debugging CSS quirks and wrestling with component libraries. Builder.io offers a powerful visual editor and component-based approach, but what if you could simply show the system what you want and have it rebuild it for you? That's where Replay comes in, using video as the source of truth to generate working code.

Understanding the Core Difference: Video vs. Components#

The fundamental distinction between Replay and Builder.io lies in their input method and underlying philosophy. Builder.io operates on a component-based model, requiring you to assemble pre-built or custom components to construct your UI. This is great for building from scratch with a clear design system in mind. Replay, on the other hand, uses video as its source of truth. It analyzes the video, understands user behavior, and reconstructs the UI based on that understanding. This "Behavior-Driven Reconstruction" is a game-changer, especially when trying to replicate existing UIs or complex flows.

Builder.io: Component-Driven Creation#

Builder.io empowers developers and designers to build and manage website content visually. You drag and drop components, configure their properties, and connect them to data sources. This provides fine-grained control and allows for rapid prototyping.

Replay: Behavior-Driven Reconstruction#

Replay takes a radically different approach. Instead of manually building with components, you provide a video recording of the UI in action. Replay's engine, powered by Gemini, analyzes the video to understand:

• •UI structure and layout
• •User interactions (clicks, scrolls, form entries)
• •Data flow and state management

From this analysis, Replay generates clean, functional code that mirrors the behavior demonstrated in the video.

Replay in Action: A Practical Example#

Imagine you want to recreate a complex checkout flow from an existing e-commerce site. With Builder.io, you'd need to meticulously recreate each component (address form, payment options, order summary) and wire them together. With Replay, you simply record a video of yourself completing the checkout flow. Replay will then generate the code for the entire flow, including the necessary components and logic.

Step 1: Record the UI#

Record a video of the existing UI you want to recreate. Ensure the video clearly shows all interactions and state changes.

Step 2: Upload to Replay#

Upload the video to Replay. The engine will begin analyzing the video and reconstructing the UI.

Step 3: Review and Refine#

Once Replay has generated the code, you can review and refine it as needed. Replay provides options for style injection and Supabase integration for data management.

typescript
// Example of generated code for handling a form submission
const handleSubmit = async (event: React.FormEvent) => {
  event.preventDefault();
  const formData = new FormData(event.currentTarget);
  const data = Object.fromEntries(formData.entries());

  try {
    const response = await fetch('/api/submit-form', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(data),
    });

    if (response.ok) {
      console.log('Form submitted successfully!');
    } else {
      console.error('Form submission failed:', response.status);
    }
  } catch (error) {
    console.error('Error submitting form:', error);
  }
};

💡 Pro Tip: For best results, ensure the video is clear, well-lit, and shows the UI in its entirety.

Key Advantages of Replay#

• •Speed: Recreate complex UIs in minutes, not hours or days.
• •Accuracy: Behavior-driven reconstruction ensures the generated code accurately reflects the original UI's behavior.
• •Flexibility: Works with any UI, regardless of the underlying framework or technology.
• •Understanding User Intent: Replay understands WHAT users are trying to do, not just what they see, leading to more functional code.
• •Multi-Page Generation: Replay can handle complex, multi-page flows.

Addressing Common Concerns#

Some might argue that video analysis is less precise than component-based construction. While it's true that Replay may require some initial refinement, the time savings and increased accuracy, especially for complex UIs, outweigh this concern. Also, Replay isn't meant to replace hand-coding entirely. It's a powerful tool for accelerating development and generating a solid foundation for further customization.

⚠️ Warning: Replay's accuracy depends on the quality of the video. Ensure the video is clear and well-lit.

Replay vs. Builder.io: A Detailed Comparison#

Building Design Systems with Replay#

Replay isn't just about replicating existing UIs; it's also a powerful tool for building design systems. By recording videos of your existing UI patterns, you can use Replay to generate the code for reusable components. This approach offers several advantages:

• •Consistency: Ensures that all components adhere to the same visual and behavioral standards.
• •Efficiency: Automates the process of creating and maintaining components.
• •Living Documentation: The videos serve as living documentation for your design system, showcasing how each component should be used.

Step 1: Identify Key Patterns#

Identify the key UI patterns in your application (e.g., buttons, forms, navigation menus).

Step 2: Record Videos#

Record videos of each pattern in action, showcasing different states and variations.

Step 3: Generate Components with Replay#

Use Replay to generate the code for each component.

Step 4: Integrate into Your Design System#

Integrate the generated components into your design system and make them available to your team.

typescript
// Example of a generated button component
import React from 'react';

interface ButtonProps {
  label: string;
  onClick: () => void;
  className?: string;
}

const Button: React.FC<ButtonProps> = ({ label, onClick, className }) => {
  return (
    <button className={`bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-4 rounded ${className}`} onClick={onClick}>
      {label}
    </button>
  );
};

export default Button;

📝 Note: Replay's style injection feature allows you to easily customize the appearance of the generated components to match your design system's branding.

Product Flow Maps#

Replay doesn't just create individual components; it understands how users navigate through your application. The "Product Flow Maps" feature visualizes the user journey, making it easier to identify areas for improvement and optimize the user experience. This is a capability that Builder.io doesn't offer natively, giving Replay a significant edge in understanding the complete user interaction.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features. Paid plans are available for more advanced functionality and higher usage limits. Check Replay Pricing

How is Replay different from v0.dev?#

While v0.dev focuses on AI-powered code generation based on text prompts, Replay uses video analysis to understand user behavior and reconstruct UIs. Replay excels at replicating existing UIs and complex flows, while v0.dev is better suited for generating new UIs from scratch.

What frameworks does Replay support?#

Replay generates framework-agnostic code that can be easily integrated into any project.

How secure is Replay?#

Replay uses industry-standard security measures to protect your data. Videos are processed securely and are not shared with third parties.

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