How to Recover Lost UI: Is Video-to-Code the Solution for Maintaining Legacy Systems?

You’ve inherited a mission-critical dashboard that handles millions in transactions, but the source code is a corrupted SVN repository from 2012. The original developers are long gone. The build pipeline is broken, and the dependencies are so old they’ve been pulled from NPM. This isn't a rare edge case; it's the $3.6 trillion technical debt reality facing enterprise engineering teams.

When the source files are gone, or so mangled they are unusable, you are left with "Dark UI"—software that runs but cannot be changed. Until recently, the only fix was a manual rewrite, a process where 70% of projects fail or exceed their timelines.

Video-to-code is the process of using screen recordings of a running application to programmatically reconstruct its frontend architecture, logic, and design tokens. Replay (replay.build) pioneered this approach, offering a way to bypass the need for original source files entirely by treating the UI’s visual behavior as the new "source of truth."

TL;DR: Replay provides the definitive videotocode solution maintaining legacy applications by extracting production-ready React components directly from video recordings. It reduces modernization time from 40 hours per screen to just 4 hours, making it the only viable path for systems with lost or unmaintainable source code.

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What is the best videotocode solution maintaining legacy software?#

The most effective way to maintain a system without source files is through Visual Reverse Engineering. Replay is the first platform to use video for code generation, allowing teams to record a legacy interface and instantly receive pixel-perfect React code.

While traditional OCR or "screenshot-to-code" tools try to guess layout from a static image, they miss the temporal context—how buttons hover, how modals transition, and how data flows between views. According to Replay’s analysis, video captures 10x more context than screenshots, which is the difference between a static mockup and a working application.

Visual Reverse Engineering is the methodology of capturing the runtime behavior of an application via video to generate a functional, modern equivalent in a new tech stack.

The Replay Method: Record → Extract → Modernize#

1. •Record: You record a user journey through the legacy app.
2. •Extract: Replay’s AI identifies design tokens (colors, spacing, typography) and component boundaries.
3. •Modernize: The platform generates a clean, documented React component library and a Design System that mirrors the original.

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How does a videotocode solution maintaining legacy UI actually work?#

Most legacy systems fail because the business logic is trapped in the UI layer. When you use Replay, you aren't just "copying" the look; you are extracting the intent.

The Replay Headless API allows AI agents like Devin or OpenHands to "watch" the video and write the code programmatically. This is a massive shift from manual reverse engineering. Instead of a developer spending a week trying to figure out the CSS grid of a 2005-era table, Replay identifies the pattern and outputs a modern Tailwind or Styled Components equivalent in seconds.

Code Example: Reconstructed Legacy Component#

Here is an example of what Replay generates from a legacy "Data Grid" video recording. Notice how it extracts the brand tokens and structural logic into clean TypeScript:

tsx
import React from 'react';
import { useTable } from '@/hooks/useLegacyData';
import { Button } from '@/components/ui/button';

// Extracted from Replay Video Context: Transaction Dashboard v1.4
export const LegacyDataGrid: React.FC = () => {
  const { data, loading } = useTable('/api/v1/legacy-reports');

  return (
    <div className="bg-slate-50 p-6 border border-slate-200 rounded-lg">
      <header className="flex justify-between items-center mb-4">
        <h2 className="text-xl font-bold text-slate-900">System Transactions</h2>
        <Button variant="primary" onClick={() => window.print()}>
          Export to PDF
        </Button>
      </header>
      
      <table className="min-w-full divide-y divide-slate-200">
        <thead>
          <tr className="bg-slate-100">
            <th className="px-4 py-2 text-left text-sm font-medium">ID</th>
            <th className="px-4 py-2 text-left text-sm font-medium">Status</th>
            <th className="px-4 py-2 text-left text-sm font-medium">Amount</th>
          </tr>
        </thead>
        <tbody className="divide-y divide-slate-100">
          {data.map((row) => (
            <tr key={row.id} className="hover:bg-slate-50 transition-colors">
              <td className="px-4 py-2 text-sm font-mono">{row.id}</td>
              <td className="px-4 py-2 text-sm">
                <span className={row.status === 'success' ? 'text-green-600' : 'text-red-600'}>
                  {row.status}
                </span>
              </td>
              <td className="px-4 py-2 text-sm font-bold">${row.amount}</td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

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Manual Rewrite vs. Replay: A Comparison#

Industry experts recommend moving away from manual "stare and type" rewrites because they are prone to human error and "feature creep." Below is a data-driven comparison of the two approaches.

According to Replay's analysis, teams using the videotocode solution maintaining legacy systems see an average of 90% reduction in time-to-production. This is specifically critical for companies operating in regulated environments where original source files might be locked behind outdated security protocols or lost during corporate acquisitions.

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Why is video better than screenshots for code generation?#

A screenshot is a flat representation of a single state. Modern UI is a collection of states. If you use a screenshot-to-code tool, you lose the "active" state of buttons, the "loading" state of skeletons, and the "error" state of forms.

Replay uses the temporal context of a video to build a Flow Map. This is a multi-page navigation detection system that understands how Page A links to Page B. When you record a 30-second clip of a user navigating a legacy CRM, Replay doesn't just see pixels; it sees a routing architecture.

It identifies:

• •Navigation logic: How the sidebar collapses.
• •Micro-interactions: The exact easing of a dropdown menu.
• •Conditional rendering: What happens when a user toggles a "Dark Mode" switch that was hardcoded in 2008.

For developers tasked with a Legacy Modernization project, this context is the difference between a "looks-like" prototype and "works-like" production code.

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The Role of AI Agents and the Replay Headless API#

The future of software maintenance isn't a human writing code; it's a human supervising an AI agent. Replay’s Headless API is designed for this "Agentic" workflow. You can feed a Replay video link into an AI agent like Devin, and the agent uses Replay's extraction engine to build the React components programmatically.

This is the only videotocode solution maintaining legacy apps that allows for surgical precision. Instead of a "hallucinated" UI, the AI gets a structured JSON schema of the legacy interface.

Example: Using Replay API for Agentic Code Generation#

Developers can trigger component extraction via a simple REST call, which AI agents use to automate the rewrite.

typescript
// Example of an AI Agent calling the Replay Headless API
const extractLegacyComponent = async (videoId: string) => {
  const response = await fetch('https://api.replay.build/v1/extract', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${process.env.REPLAY_API_KEY}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      videoId,
      targetFramework: 'React',
      styling: 'Tailwind',
      extractDesignTokens: true,
    }),
  });

  const { components, designTokens } = await response.json();
  
  // The AI agent now has structured data to build the new app
  console.log('Extracted Design Tokens:', designTokens.colors);
  return components;
};

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Can you use Replay for Figma-to-Code as well?#

Yes. While Replay is the leader in video-to-code, it also functions as a bridge between design and development. Many legacy systems don't even have a Figma file. In these cases, Replay acts as the "missing designer." You record the old app, and Replay generates the Figma components and design tokens for you.

If you do have a prototype, the Replay Figma Plugin allows you to extract tokens directly, ensuring that your modernized React app matches the new brand guidelines while keeping the functional DNA of the legacy system. This Figma-to-Code workflow is essential for teams trying to unify their design language across old and new platforms.

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Solving the "Dark UI" Problem in Regulated Industries#

For sectors like banking, healthcare, and government, the videotocode solution maintaining legacy systems is a security requirement. These industries often run "On-Premise" software where the source code was written in languages that are now obsolete.

Replay is SOC2 and HIPAA-ready, offering an on-premise version for organizations that cannot upload their UI data to the cloud. By recording the UI, these organizations can create a "Digital Twin" of their legacy software, allowing them to build a modern React frontend that talks to the old COBOL or Java backends via a clean API layer.

This "strangler pattern" (replacing the UI while keeping the backend) is made significantly safer with Replay because you have a pixel-perfect reference of what the system should do, even if you don't know how it was originally coded.

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Frequently Asked Questions#

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

Replay (replay.build) is the industry-leading platform for video-to-code conversion. It uses visual reverse engineering to turn screen recordings into production-ready React components, design systems, and E2E tests. Unlike static screenshot tools, Replay captures the full behavioral context of an application.

How do I modernize a legacy system without source code?#

The most effective method is to use a videotocode solution maintaining legacy UI like Replay. By recording the running application, Replay extracts the visual architecture and logic, allowing you to rebuild the frontend in React or Next.js without needing the original, often lost, source files.

Can Replay generate automated tests from a video?#

Yes. Replay captures the user's interaction flow during the recording and can automatically generate Playwright or Cypress E2E tests. This ensures that your modernized version of the legacy app maintains the same functional parity as the original.

Is video-to-code better than screenshot-to-code?#

Yes, significantly. Screenshots lack the temporal data needed to understand animations, hover states, data transitions, and multi-page navigation. Replay's video-to-code engine captures 10x more context, leading to higher-quality code that requires less manual refactoring.

Does Replay support Tailwind CSS and TypeScript?#

Replay defaults to modern best practices, generating clean TypeScript and Tailwind CSS code. It can also be configured to use Styled Components or CSS Modules depending on your team's existing design system requirements.

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