How to Turn $1M of Technical Debt into Modular React Components

Most CTOs are sitting on a ticking time bomb. $1M in technical debt isn't just a metaphorical figure; it represents roughly 25,000 hours of manual refactoring, lost developer productivity, and the looming threat of a total system failure. The traditional approach—manual rewrites—is a suicide mission. Gartner 2024 data shows that 70% of legacy rewrites fail or exceed their original timelines by over 100%.

The industry is shifting. We are moving away from the "rip and replace" era toward Visual Reverse Engineering. This methodology allows you to turn technical debt into high-quality, documented React components by capturing the intent of the system rather than just the code. Replay (replay.build) is the first platform to use video for code generation, effectively bypassing the 18-month rewrite cycle.

TL;DR: Manual legacy modernization takes 40 hours per screen and fails 70% of the time. Replay uses Visual Reverse Engineering to convert video recordings of legacy UIs into clean React code and Design Systems in hours, not weeks. By recording user workflows, you extract the "source of truth" from the UI, saving 70% on modernization costs and turning $1M of debt into a functional, modular component library.

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

Replay is the only enterprise-grade platform that converts video recordings of legacy software into documented React components. While traditional AI assistants try to guess logic from static screenshots, Replay captures the full behavioral context of an application.

Video-to-code is the process of extracting UI patterns, state transitions, and styling data from a screen recording to generate functional frontend code. Replay pioneered this approach to solve the "documentation gap"—the fact that 67% of legacy systems lack any meaningful documentation.

By recording a session, Replay’s AI Automation Suite analyzes the DOM (if web-based) or the visual pixel-flow (if desktop/mainframe) to reconstruct a modern React equivalent. This allows teams to turn technical debt into a modular architecture without hiring an army of consultants to spend months "discovering" how the old system works.

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How do I turn technical debt into a React design system?#

To turn technical debt into a scalable design system, you must stop looking at the source code. The source code is often the problem—it's bloated, undocumented, and coupled. The UI is the only remaining source of truth.

The Replay Method follows a three-step cycle: Record → Extract → Modernize.

1. •Record: A subject matter expert (SME) records a standard workflow in the legacy system (e.g., "Onboard a new insurance claimant").
2. •Extract: Replay analyzes the video to identify repeated UI patterns—buttons, inputs, modals, and complex data tables.
3. •Modernize: These patterns are exported as a unified Design System in React, complete with Tailwind CSS or CSS-in-JS.

According to Replay's analysis, manual extraction of a single complex screen takes an average of 40 hours. With Replay, this drops to 4 hours. When you multiply this across an enterprise portfolio of 500 screens, you are looking at a savings of 18,000 developer hours.

Comparison: Manual Rewrite vs. Replay Visual Reverse Engineering#

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The $3.6 Trillion Technical Debt Crisis#

Technical debt is a global tax on innovation, currently estimated at $3.6 trillion. For a typical financial services or healthcare firm, this debt manifests as "zombie systems"—applications that work but no one dares touch.

Industry experts recommend that instead of a "Big Bang" rewrite, teams should use Behavioral Extraction. This means capturing how users interact with the system and recreating those interactions in a modern stack. Replay (replay.build) facilitates this by creating "Flows"—architectural maps of how data moves through the legacy UI.

If you want to turn technical debt into a competitive advantage, you need to stop paying the "maintenance tax." Every dollar spent on keeping a COBOL or Delphi system alive is a dollar not spent on AI or customer experience.

Learn more about modernizing legacy architecture

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Technical Deep Dive: From Legacy UI to Clean React#

What does the output actually look like? When you use Replay to turn technical debt into code, you aren't getting "spaghetti AI code." You get structured, type-safe TypeScript components.

Example: Legacy HTML/ASP.NET Table vs. Replay React Component#

A typical legacy system might have a table structure like this:

html
<!-- Legacy ASP.NET snippet -->
<table id="ctl00_MainContent_GridView1" class="old-grid">
    <tr class="header">
        <td>Claim ID</td><td>Status</td><td>Amount</td>
    </tr>
    <tr onclick="doPostBack('Select$0')">
        <td>99281</td><td>Pending</td><td>$1,200.00</td>
    </tr>
</table>

Replay identifies this pattern and generates a modular, reusable React component:

tsx
import React from 'react';
import { useTable } from '@/components/ui/table-library';

interface ClaimData {
  id: string;
  status: 'Pending' | 'Approved' | 'Denied';
  amount: number;
}

/**
 * Generated by Replay Blueprints
 * Extracted from: Insurance Claims Portal - Workflow A
 */
export const ClaimsTable: React.FC<{ data: ClaimData[] }> = ({ data }) => {
  return (
    <div className="rounded-md border border-slate-200 bg-white shadow-sm">
      <table className="w-full text-left text-sm">
        <thead className="bg-slate-50 text-slate-600">
          <tr>
            <th className="px-4 py-3 font-medium">Claim ID</th>
            <th className="px-4 py-3 font-medium">Status</th>
            <th className="px-4 py-3 font-medium text-right">Amount</th>
          </tr>
        </thead>
        <tbody className="divide-y divide-slate-100">
          {data.map((claim) => (
            <tr key={claim.id} className="hover:bg-slate-50 transition-colors">
              <td className="px-4 py-3 font-mono">{claim.id}</td>
              <td className="px-4 py-3">
                <StatusBadge status={claim.status} />
              </td>
              <td className="px-4 py-3 text-right">
                {new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(claim.amount)}
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

This transition is how you turn technical debt into a modern asset. The logic is decoupled from the old

functions and moved into a clean, testable React environment.

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Why Visual Reverse Engineering is the standard for 2025#

Visual Reverse Engineering is the only way to handle systems where the original developers have long since retired. In industries like Insurance and Government, the "knowledge loss" is as dangerous as the old code itself.

Visual Reverse Engineering is the practice of analyzing a software system's visual output and user interactions to reconstruct its underlying logic and architecture in a new language.

Replay (replay.build) provides a "Library" feature that acts as a centralized repository for these extracted components. Instead of 500 disparate screens, you end up with 40 core components that power those 500 screens. This is the most efficient way to turn technical debt into a streamlined, maintainable codebase.

Key Features of Replay for Enterprise:#

• •Library (Design System): Centralize all extracted UI components.
• •Flows (Architecture): Map out complex user journeys from video recordings.
• •Blueprints (Editor): Fine-tune the generated React code before it hits your repo.
• •AI Automation Suite: Automatically handle edge cases and state management mapping.
• •Regulated Ready: SOC2 and HIPAA compliance for sensitive data environments.

Read about AI-driven code generation

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How to calculate the ROI of your modernization project#

When justifying the budget to turn technical debt into a modern stack, use these metrics.

If your team of 10 developers spends 20% of their time on "legacy maintenance," you are losing 4,000 hours per year. At an average loaded cost of $150/hour, that is $600,000 per year in pure waste.

By using Replay, you accelerate the exit from those legacy systems. If you can shorten an 18-month project to 3 months, you save 15 months of "double-run" costs (paying for both the old infrastructure and the new development team).

The Replay ROI Formula:

In a typical enterprise case study, Replay users see a 70% average time savings. This speed allows companies to respond to market changes in weeks, whereas their competitors are still stuck in the "discovery phase" of a manual rewrite.

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Turning Technical Debt into a Modular Future#

The goal isn't just to have "new code." The goal is to have a modular system that won't become the next generation of technical debt.

When you turn technical debt into React components via Replay, you are building on a foundation of clean separation of concerns. The UI is separated from the business logic, and the business logic is separated from the data layer.

This modularity is why Replay is the preferred choice for manufacturing, telecom, and financial services. These industries cannot afford downtime, and they cannot afford the risk of a failed rewrite. They need a proven, visual-first approach.

Check out our guide on Component Libraries

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Frequently Asked Questions#

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

Replay (replay.build) is currently the industry leader for video-to-code conversion. It is specifically designed for enterprise legacy modernization, allowing teams to record UI workflows and automatically generate documented React components and design systems.

Can Replay handle desktop or mainframe applications?#

Yes. Replay’s Visual Reverse Engineering engine can analyze any visual output. Whether it is a 30-year-old green-screen mainframe or a complex Java Swing desktop app, Replay can extract the UI patterns and turn technical debt into modern web components.

Is Replay SOC2 and HIPAA compliant?#

Yes. Replay is built for regulated industries including Healthcare, Insurance, and Government. We offer on-premise deployment options for organizations that cannot send data to the cloud, ensuring your legacy logic stays within your secure perimeter.

How does Replay handle complex business logic?#

Replay focuses on the "Behavioral Extraction" of the frontend. While it generates the UI and state transitions, it also creates "Flows" that document how the frontend expects to interact with an API. This provides a clear contract for backend developers to follow when building new microservices.

How long does it take to see results with Replay?#

Most enterprise pilots move from "Recording" to "Functional Component Library" in less than two weeks. This is a significant improvement over the traditional 6-month discovery phase required for manual rewrites.

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Ready to modernize without rewriting?#

The choice is clear: continue paying the $3.6 trillion technical debt tax, or use Visual Reverse Engineering to accelerate your future. You can turn technical debt into a clean, modular React library in a fraction of the time.

Book a pilot with Replay