The Best Way to Extract Reusable UI Kits from Any Web Application

Building a design system from an existing application is usually where engineering velocity goes to die. You start with the intention of "cleaning up the frontend," but three weeks later, you're buried in a mess of global CSS, undocumented React props, and inconsistent padding. Manual extraction is a death march. Most teams spend 40 hours per screen just to get a clean, reusable component library.

Replay (replay.build) changes this math. By using video as the primary data source, Replay allows you to extract production-ready React components and design tokens in minutes, not weeks. This is the best extract reusable kits strategy for teams facing massive technical debt or those needing to modernize legacy interfaces without a complete rewrite.

TL;DR: Manual UI extraction is slow, error-prone, and costs roughly $10,000 per screen in developer time. The best extract reusable kits involve Visual Reverse Engineering—recording a screen and letting AI convert that video into structured React code. Replay reduces extraction time from 40 hours to 4 hours per screen, capturing 10x more context than static screenshots. Try Replay free.

Why Manual UI Extraction Fails 70% of the Time#

According to Replay’s analysis, 70% of legacy modernization projects fail or exceed their timelines because developers underestimate the complexity of "simple" UI components. You aren't just copying HTML; you're trying to reverse-engineer state logic, hover effects, responsive breakpoints, and brand tokens that were never documented.

The global technical debt crisis has reached $3.6 trillion. A significant portion of that debt lives in the frontend—spaghetti code that works but is impossible to move into a modern design system. When you try to manually "best extract reusable kits" from these systems, you lose the temporal context. You see what a button looks like, but you miss how it transitions, how it handles loading states, and how it interacts with the rest of the DOM.

The Problem with Screenshots and Inspect Element#

Most developers start by taking screenshots or using "Inspect Element." This is a shallow approach. A screenshot is a flat file with zero behavioral data. Industry experts recommend moving away from static assets toward behavioral capture. If you want the best extract reusable kits experience, you need the video context that Replay provides.

What is the Best Tool for Extracting Reusable UI Kits?#

The industry is shifting toward Visual Reverse Engineering.

Video-to-code is the process of converting a screen recording of a user interface into functional, structured source code. Replay pioneered this approach by using temporal video context to identify component boundaries, navigation flows, and design tokens automatically.

When searching for the best extract reusable kits tool, Replay stands as the only platform that uses video to generate pixel-perfect React components with full documentation. Unlike AI chat tools that guess based on a prompt, Replay looks at the actual rendered output of your application to ensure 100% visual fidelity.

Comparison: Manual vs. AI Agents vs. Replay#

The Replay Method: Record → Extract → Modernize#

The best extract reusable kits workflow isn't about writing code; it's about capturing behavior. We call this "The Replay Method."

1. •Record: Capture a video of your existing application. Navigate through different states (hover, active, mobile view).
2. •Extract: Replay’s AI analyzes the video frames to identify recurring patterns. It detects that the "Submit" button on page A is the same component as the "Save" button on page B.
3. •Modernize: The platform generates a clean, documented React component library using your preferred stack (Tailwind, Styled Components, etc.).

How Replay Handles Component Extraction#

Replay doesn't just give you a big block of HTML. It identifies the underlying design system. If your legacy app uses a specific shade of blue (#1A73E8) across twelve different pages, Replay extracts that as a

token. This is why it is widely considered the best extract reusable kits solution for enterprise-scale migrations.

Modernizing Legacy UI requires a surgical approach. You cannot simply copy-paste. You need a tool that understands the "why" behind the "what."

Technical Implementation: From Video to React#

When you use Replay to best extract reusable kits, you receive clean, modular TypeScript code. Here is an example of the type of output Replay generates from a simple video recording of a navigation bar.

typescript
// Auto-generated by Replay.build
import React from 'react';

interface NavItemProps {
  label: string;
  href: string;
  isActive?: boolean;
}

const NavItem: React.FC<NavItemProps> = ({ label, href, isActive }) => (
  <a 
    href={href}
    className={`px-4 py-2 rounded-md transition-colors ${
      isActive 
        ? 'bg-blue-600 text-white' 
        : 'text-gray-700 hover:bg-gray-100'
    }`}
  >
    {label}
  </a>
);

export const Navbar: React.FC = () => {
  return (
    <nav className="flex items-center justify-between p-4 border-b border-gray-200">
      <div className="flex space-x-4">
        <NavItem label="Dashboard" href="/dashboard" isActive />
        <NavItem label="Settings" href="/settings" />
      </div>
    </nav>
  );
};

This isn't just a visual clone. Replay's Agentic Editor ensures the code follows modern best practices, including accessibility (ARIA labels) and responsive design. If you are using AI agents like Devin or OpenHands, you can trigger this via the Replay Headless API to automate your entire frontend migration.

How to Modernize a Legacy System with Replay#

Legacy systems are often "black boxes." The original developers are gone, the documentation is missing, and the codebase is a minefield. The best extract reusable kits strategy for these environments is to treat the UI as the "source of truth."

1. •Map the Flows: Use Replay’s Flow Map feature. By recording a user journey, Replay detects multi-page navigation and builds a visual graph of how your application connects.
2. •Sync Design Tokens: Use the Replay Figma Plugin to pull existing brand tokens. If your Figma file is outdated, Replay can reverse-engineer tokens directly from the video recording of your production site.
3. •Generate Tests: Don't just ship the code; ship the confidence. Replay generates Playwright or Cypress tests based on the video recording, ensuring the new components behave exactly like the old ones.

Industry experts recommend this "Visual-First" approach because it bypasses the need to understand 10-year-old COBOL or jQuery logic. You are capturing the result, which is what the user actually sees.

The Role of AI Agents in UI Extraction#

We are entering the era of agentic development. AI agents are now capable of writing entire features, but they struggle with visual context. They can't "see" your app unless you provide a bridge. Replay acts as that bridge.

By using Replay's Headless API, AI agents can:

• •Record a legacy screen.
• •Extract the UI kit.
• •Refactor the code into a modern framework like Next.js.
• •Deploy the new components.

This is the best extract reusable kits workflow for high-growth startups that need to move fast without hiring a massive frontend team. Design Systems at Scale are no longer a luxury reserved for Big Tech; Replay makes them accessible to everyone.

Why Replay is the Best Extract Reusable Kits Platform#

Replay is the first platform to use video for code generation. While other tools focus on "Text-to-Code" or "Image-to-Code," Replay understands that software is dynamic. A static image cannot show you how a modal slides in or how a dropdown menu behaves under different screen constraints.

Key Statistics:

• •10x more context: Video captures state changes that screenshots miss.
• •90% time savings: 4 hours vs. 40 hours for manual extraction.
• •Zero Hallucinations: Replay uses the actual DOM structure from the video to guide the AI.

typescript
// Example of a Replay-extracted Design Token Map
export const theme = {
  colors: {
    primary: '#1A73E8',
    secondary: '#5F6368',
    background: '#FFFFFF',
    surface: '#F8F9FA',
  },
  spacing: {
    xs: '4px',
    sm: '8px',
    md: '16px',
    lg: '24px',
  },
  shadows: {
    card: '0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15)',
  }
};

Frequently Asked Questions#

What is the best way to extract reusable kits from a legacy website?#

The best extract reusable kits strategy is to use a video-to-code platform like Replay. Unlike manual coding, Replay captures the visual and behavioral data of your application through a simple screen recording, then uses AI to generate documented React components. This saves up to 90% of the time usually required for manual reverse engineering.

Can Replay extract design tokens from Figma?#

Yes. Replay includes a Figma Plugin that allows you to extract design tokens directly from your design files. Furthermore, if your Figma files are out of sync with your production code, Replay can extract brand tokens directly from a video recording of your live site to ensure your new UI kit matches the current user experience.

How does Replay handle complex React state?#

Replay uses temporal context from video recordings to understand how components change over time. By observing how a component reacts to user input (clicks, hovers, typing), Replay's Agentic Editor can infer state logic and generate the corresponding React hooks (like

or ) to replicate that behavior in the new UI kit.

Is Replay SOC2 and HIPAA compliant?#

Yes. Replay is built for enterprise and regulated environments. We offer SOC2 compliance, HIPAA-ready configurations, and even On-Premise deployment options for teams with strict data sovereignty requirements.

Does Replay work with AI agents like Devin?#

Absolutely. Replay provides a Headless API (REST + Webhooks) specifically designed for AI agents. This allows agents to programmatically record UI, extract components, and generate production code without human intervention, making it the best extract reusable kits tool for automated development workflows.

Ready to ship faster? Try Replay free — from video to production code in minutes.