Replay AI: Rebuilding Design Systems From Existing Web Applications in 2026

TL;DR: Replay AI leverages video analysis and behavior-driven reconstruction to rebuild design systems from existing web applications, offering a faster and more accurate approach compared to traditional screenshot-based or manual methods.

Rebuilding design systems from existing web applications is a common, yet incredibly tedious task. Traditional approaches often involve reverse-engineering code, manually documenting components, or relying on static screenshots. These methods are time-consuming, error-prone, and struggle to capture the dynamic behavior of modern web UIs. Imagine trying to reconstruct the intricate animations and state management of a complex dashboard just from static images. Nightmare fuel, right?

Fortunately, a new paradigm is emerging: behavior-driven reconstruction. And at the forefront of this revolution is Replay.

The Problem: Design System Reverse Engineering is Painful#

Manually rebuilding design systems is a recipe for frustration. Here’s why:

• •Static Images Lack Context: Screenshots provide a visual representation but fail to capture interactive elements, animations, and state changes.
• •Code Reverse Engineering is Time-Consuming: Diving into existing codebases to extract component logic and styles is a slow and error-prone process.
• •Documentation is Often Outdated: Existing documentation may not reflect the current state of the application, leading to inconsistencies and rework.
• •Maintaining Consistency is Difficult: Ensuring all components adhere to the design system's principles requires meticulous attention to detail and constant vigilance.

This is precisely the gap Replay aims to fill.

Replay: Video as the Source of Truth#

Replay approaches design system reconstruction differently. Instead of relying on static assets or manual code analysis, Replay uses video recordings of the existing application as the primary source of truth. By analyzing user interactions and UI behavior captured in video, Replay can automatically reconstruct functional UI components and their associated styles. This "Behavior-Driven Reconstruction" offers several key advantages:

• •Captures Dynamic Behavior: Replay understands how components respond to user input, including animations, state changes, and data updates.
• •Automates Component Extraction: Replay automatically identifies and extracts reusable UI components from the video recording.
• •Generates Functional Code: Replay generates clean, well-structured code that accurately reflects the behavior of the original components.
• •Facilitates Design System Integration: Replay makes it easy to integrate reconstructed components into an existing design system.

How Replay Works: Under the Hood#

Replay leverages advanced AI algorithms, including Gemini, to analyze video recordings and reconstruct UI components. The process typically involves the following steps:

1. •Video Upload and Processing: The user uploads a video recording of the target application.
2. •Behavioral Analysis: Replay analyzes the video to identify UI elements, user interactions, and state changes. This involves object detection, action recognition, and state management analysis.
3. •Component Reconstruction: Based on the behavioral analysis, Replay reconstructs the UI components, including their structure, styles, and functionality.
4. •Code Generation: Replay generates clean, well-structured code for the reconstructed components, typically in React, Vue, or Angular.
5. •Integration and Customization: The user can integrate the generated code into their design system and customize the components as needed.

Step 1: Recording the Application#

Use any screen recording tool to capture the application's behavior. Focus on demonstrating all states and interactions of the components you want to rebuild.

Step 2: Uploading to Replay#

Upload the video to Replay. The AI engine will begin analyzing the video.

Step 3: Reviewing and Refining#

Replay will present a breakdown of the identified components. Review and refine the results as needed. You can adjust the component boundaries and specify component names.

Step 4: Code Generation and Integration#

Generate the code and integrate it into your design system.

typescript
// Example of a reconstructed React component generated by Replay
import React, { useState } from 'react';
import './ReconstructedButton.css'; // Injected styles

interface ReconstructedButtonProps {
  label: string;
  onClick: () => void;
}

const ReconstructedButton: React.FC<ReconstructedButtonProps> = ({ label, onClick }) => {
  const [isHovered, setIsHovered] = useState(false);

  return (
    <button
      className={`reconstructed-button ${isHovered ? 'hovered' : ''}`}
      onClick={onClick}
      onMouseEnter={() => setIsHovered(true)}
      onMouseLeave={() => setIsHovered(false)}
    >
      {label}
    </button>
  );
};

export default ReconstructedButton;

💡 Pro Tip: Focus your initial recordings on components with clear, distinct behaviors. This makes it easier for Replay to accurately reconstruct them.

Replay Features: Powering Design System Reconstruction#

Replay offers a range of features designed to streamline the design system reconstruction process:

• •Multi-Page Generation: Replay can analyze videos spanning multiple pages, allowing for the reconstruction of complex product flows.
• •Supabase Integration: Seamlessly integrate Replay with Supabase to manage data and backend logic.
• •Style Injection: Replay can inject styles directly into the generated components, ensuring visual consistency with the original application.
• •Product Flow Maps: Replay generates visual maps of user flows, providing valuable insights into user behavior.

Replay vs. Traditional Methods: A Comparison#

Addressing Common Concerns#

• •Video Quality: Replay requires reasonably clear video recordings to accurately analyze UI elements and user interactions. However, it is surprisingly resilient to minor imperfections.
• •Complex Animations: While Replay excels at capturing dynamic behavior, extremely complex animations may require manual refinement.
• •Accuracy Limitations: Although Replay is designed to generate accurate code, manual review and customization may be necessary in some cases.

⚠️ Warning: Ensure the video recording clearly showcases all states and interactions of the components you want to reconstruct.

The Future of Design Systems: Behavior-Driven Development#

Replay represents a significant step towards the future of design systems, where behavior-driven development becomes the norm. By leveraging video analysis and AI-powered reconstruction, Replay empowers developers to rebuild design systems faster, more accurately, and with greater confidence. Imagine a world where design systems are automatically updated based on real user behavior. That's the future Replay is building.

Here are some potential benefits:

• •Faster iteration cycles for design systems.
• •Reduced manual effort in component creation and maintenance.
• •Improved consistency and accuracy in UI implementations.
• •Enhanced understanding of user behavior and design effectiveness.

Frequently Asked Questions#

Is Replay free to use?#

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

How is Replay different from v0.dev?#

While both tools aim to generate code from visual inputs, Replay distinguishes itself by using video recordings as the primary input source. This allows Replay to capture dynamic behavior and user interactions, providing a more complete and accurate representation of the UI. V0.dev primarily uses text prompts and component libraries to generate code.

What types of applications can Replay reconstruct?#

Replay can reconstruct a wide range of web applications, including e-commerce sites, dashboards, and mobile apps. The key requirement is that the application can be captured in a video recording.

What code languages and frameworks does Replay support?#

Currently, Replay primarily supports React, Vue, and Angular. Support for other languages and frameworks is planned for future releases.

How does Replay handle authentication and data fetching?#

Replay can analyze authentication flows and data fetching patterns in the video recording. It can generate code that handles authentication and data fetching using common libraries and frameworks. Supabase integration further simplifies backend management.

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