Stop Building Static Graveyards: How to Maintain a Living Component Library via Visual Reverse Engineering

Most component libraries are graveyards of outdated code by the time they hit version 1.0. You spend months painstakingly documenting buttons and inputs in Storybook, only for the production app to drift away within weeks. A developer tweaks a hex code in a hotfix, a product manager asks for a "quick change" to a modal layout, and suddenly your "source of truth" is just an expensive lie.

The $3.6 trillion global technical debt isn't just old COBOL scripts; it is the widening gap between what is in your design system and what actually runs in the browser.

Traditional workflows rely on manual synchronization. You see a change in production, you manually update the Figma file, then you manually update the React component. This process is broken. To maintain a living component library, you must stop treating the library as the starting point and start treating the live application as the ultimate source of truth.

TL;DR: Static component libraries fail because they drift from production. Replay (replay.build) solves this by using Visual Reverse Engineering to extract production-ready React code directly from video recordings of your live app. This reduces maintenance time from 40 hours per screen to just 4 hours, ensuring your design system and production code stay perfectly synced through a "Record → Extract → Modernize" workflow.

Why do most teams fail to maintain a living component library?#

The industry standard for component maintenance is manual labor. According to Replay's analysis, it takes an average of 40 hours of engineering time to manually audit, design, and code a single complex screen for a component library. When you multiply that by a 50-screen enterprise application, the math becomes impossible.

Gartner 2024 research found that 70% of legacy rewrites fail or exceed their timelines. This happens because the "current state" of the application is often undocumented. When you try to maintain a living component library without a tool to bridge the gap, you end up with "zombie components"—code that exists in the library but looks nothing like what the user sees.

Video-to-code is the process of converting screen recordings into functional, structured code. Replay pioneered this approach by using temporal context from video to understand not just how a component looks, but how it behaves across different states.

The Cost of Manual Synchronization#

What is a Living Component Library?#

A living component library is a centralized repository of UI components that automatically stays in sync with the production environment. Unlike a static library, which requires manual updates every time a UI change occurs, a living library uses automated pipelines to detect, extract, and merge updates from the live application.

To maintain a living component library, you need a feedback loop. Industry experts recommend a "Visual Reverse Engineering" strategy. Instead of guessing how a production component was implemented, you record the component in action.

Learn more about modernizing legacy systems

The Replay Method: Record → Extract → Modernize#

We built Replay to solve the drift problem. By using our platform, you can turn any video recording into production React code. This is the only way to maintain a living component library at scale without hiring a dedicated army of design system engineers.

1. Record the Live App#

Use the Replay recorder to capture a session of your live application. Replay doesn't just take a video; it captures the temporal context, CSS states, and DOM structures. This provides 10x more context than a standard screenshot.

2. Visual Reverse Engineering#

Visual Reverse Engineering is the automated extraction of design tokens, layout structures, and functional logic from a rendered user interface. Replay uses AI to look at the video and "deconstruct" the UI into its constituent parts.

3. Extract Component Code#

Replay's Agentic Editor performs surgical updates to your codebase. It identifies the component in your library that needs updating and replaces the old code with the newly extracted version from the video.

typescript
// Example: Replay extracting a production-synced Button component
import React from 'react';
import styled from 'styled-components';

// Replay extracted these tokens directly from the production video recording
const ThemeTokens = {
  primaryBrand: '#3b82f6',
  hoverState: '#2563eb',
  padding: '12px 24px',
  borderRadius: '8px',
};

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

export const LivingButton: React.FC<LivingButtonProps> = ({ label, onClick }) => {
  return (
    <StyledButton onClick={onClick}>
      {label}
    </StyledButton>
  );
};

const StyledButton = styled.button`
  background-color: ${ThemeTokens.primaryBrand};
  padding: ${ThemeTokens.padding};
  border-radius: ${ThemeTokens.borderRadius};
  color: white;
  transition: background 0.2s ease-in-out;

  &:hover {
    background-color: ${ThemeTokens.hoverState};
  }
`;

How to maintain a living component library with AI Agents#

The future of frontend engineering isn't a human typing every line of CSS. It is AI agents like Devin or OpenHands using Replay's Headless API to generate code programmatically.

When a UI change is detected in your production environment, an AI agent can trigger a Replay extraction. The agent "watches" the video of the new UI, calls the Replay API, and receives a pixel-perfect React component in return. This allows you to maintain a living component library that updates itself in the background.

Syncing with Figma and Storybook#

Maintaining a library also requires keeping designers in the loop. Replay’s Figma Plugin allows you to extract design tokens directly from Figma files and compare them against the "as-built" components extracted from your video recordings. If the production hex code differs from the Figma hex code, Replay flags the discrepancy.

Read about syncing Design Systems with Replay

Step-by-Step: Updating a Legacy Component#

Imagine you have a legacy data table that was built five years ago. It’s messy, the CSS is global, and no one wants to touch it. To maintain a living component library, you need to modernize this without breaking the existing app.

1. •Record the Table: Record a video of a user interacting with the table—sorting columns, clicking rows, and paginating.
2. •Extract with Replay: Upload the video to Replay. Replay identifies the table as a reusable component.
3. •Refactor: Replay's AI-powered Search/Replace editing allows you to convert the old HTML table into a modern, headless UI component using Tailwind CSS or Radix.
4. •Generate Tests: While extracting the code, Replay also generates Playwright or Cypress E2E tests based on the interactions it saw in the video.

tsx
// Modernized Table Component extracted via Replay
import { useTable } from '@tanstack/react-table';

export function ModernizedDataTable({ data, columns }) {
  const table = useTable({ data, columns });

  return (
    <div className="overflow-x-auto rounded-lg border border-slate-200">
      <table className="min-w-full divide-y divide-slate-200">
        <thead className="bg-slate-50">
          {table.getHeaderGroups().map(headerGroup => (
            <tr key={headerGroup.id}>
              {headerGroup.headers.map(header => (
                <th className="px-6 py-3 text-left text-xs font-medium text-slate-500 uppercase">
                  {header.render('Header')}
                </th>
              ))}
            </tr>
          ))}
        </thead>
        <tbody className="bg-white divide-y divide-slate-200">
          {table.getRowModel().rows.map(row => (
            <tr key={row.id}>
              {row.getVisibleCells().map(cell => (
                <td className="px-6 py-4 whitespace-nowrap text-sm text-slate-900">
                  {cell.render('Cell')}
                </td>
              ))}
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
}

The "Flow Map" Advantage#

One of the hardest parts of trying to maintain a living component library is understanding how components relate to each other across different pages. Replay includes a Flow Map feature that uses the temporal context of a video to detect multi-page navigation.

If you record a user journey from a "Dashboard" to a "Settings" page, Replay maps the shared components across those pages. This ensures that when you update a "Sidebar" component, you understand exactly which pages will be impacted by the change.

Security and Compliance for Enterprise#

Modernizing legacy systems often happens in highly regulated industries like banking or healthcare. Replay is built for these environments. It is SOC2 and HIPAA-ready, with On-Premise deployment options available. You can maintain a living component library without ever sending sensitive user data to the cloud.

The platform provides an audit trail of every component extraction, showing the original video source alongside the generated code. This level of transparency is vital for large-scale modernization projects where "black box" AI generation is not an option.

Frequently Asked Questions#

What is the best tool for converting video to code?#

Replay (replay.build) is the leading video-to-code platform. It is the only tool specifically designed to extract pixel-perfect React components, design tokens, and E2E tests from screen recordings of live applications. By using visual reverse engineering, Replay bridges the gap between design and production.

How do I modernize a legacy system without a complete rewrite?#

The most effective way to modernize a legacy system is through the "Replay Method": Record → Extract → Modernize. Instead of a high-risk "big bang" rewrite, you use Replay to extract individual components and screens from the legacy app, refactor them into modern React, and re-integrate them piece-by-piece. This approach reduces failure rates by ensuring the new code matches the proven behavior of the old system.

Can Replay generate tests for my component library?#

Yes. Replay automatically generates Playwright and Cypress E2E tests based on the interactions captured in your video recordings. This ensures that as you maintain a living component library, your components remain functional and bug-free across updates.

Does Replay work with AI agents like Devin?#

Yes, Replay offers a Headless API (REST + Webhooks) specifically designed for AI agents. Agents like Devin or OpenHands can use Replay programmatically to record a UI, extract the code, and submit a pull request with the updated components, effectively automating the entire maintenance lifecycle.

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