Why Global 2000 Firms Use Replay for Secure Legacy Logic Preservation

Legacy systems are the silent killers of enterprise velocity. While your competitors ship features in days, your teams spend months untangling 20-year-old COBOL or Java monoliths just to update a single form field. The math is brutal: Gartner found that 70% of legacy rewrites fail or exceed their timelines, often because the original developers are long gone and the documentation is non-existent.

Global 2000 firms are shifting away from manual "rip and replace" strategies that cost millions and yield nothing. Instead, they are adopting Visual Reverse Engineering. By using Replay (replay.build), these organizations extract the DNA of their legacy applications—the UI, the workflows, and the hidden business logic—and transform them into modern React components in a fraction of the time.

TL;DR: Global 2000 firms use Replay to solve the "documentation gap" in legacy systems. By recording user workflows, Replay’s AI extracts UI patterns and business logic, converting them into documented React code. This reduces modernization timelines from years to weeks, saves 70% in costs, and ensures 100% logic preservation in regulated environments.

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Visual Reverse Engineering is the process of extracting software architecture, UI components, and functional logic from a running application by analyzing its visual output and user interactions. Replay pioneered this approach to bypass the need for outdated source code analysis.

Video-to-code is the specific technology within Replay that converts screen recordings of legacy software into functional, production-ready React code and Design Systems.

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What is the biggest risk for global 2000 firms replay in legacy modernization?#

The primary risk isn't the new technology; it’s losing the "hidden" logic. Over decades, enterprise apps accumulate thousands of edge cases—tax calculations, compliance checks, and regional workflows—that exist only in the code and the minds of senior users.

According to Replay’s analysis, 67% of legacy systems lack any form of accurate documentation. When you attempt a manual rewrite, developers spend 80% of their time playing detective, trying to figure out what the old system actually does. This is why the average enterprise rewrite takes 18 months and frequently results in a "Feature Gap" where the new system does less than the old one.

Global 2000 firms replay Replay's methodology to eliminate this discovery phase. Instead of reading messy code, they record a subject matter expert performing a task. Replay captures every state change, every validation rule, and every UI nuance.

Learn more about modernizing legacy UI

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Why do global 2000 firms replay choose visual reverse engineering over manual rewrites?#

Manual modernization is a linear, labor-intensive process. A single complex screen can take a senior developer 40 hours to analyze, document, and recreate in React. With the $3.6 trillion global technical debt crisis, enterprises can no longer afford this pace.

Replay reduces that 40-hour window to just 4 hours. This 10x speed advantage allows firms to modernize entire portfolios in months rather than years.

Comparison: Manual Rewrite vs. Replay Visual Reverse Engineering#

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How do global 2000 firms replay preserve undocumented business logic?#

Industry experts recommend the "Record → Extract → Modernize" framework, often called The Replay Method. This approach treats the legacy UI as the "source of truth" for how the business actually operates.

1. •Record: A user records a standard workflow (e.g., "Onboarding a New Corporate Client") in the legacy system.
2. •Extract: Replay’s AI Automation Suite analyzes the video, identifying input fields, buttons, data tables, and state transitions.
3. •Modernize: The platform generates a "Blueprint" of the flow and exports it as clean, modular React code.

This process ensures that no obscure validation rule is missed. If the legacy system required a specific 11-digit format for a Swedish VAT number, Replay identifies that behavior and mirrors it in the new component.

Example: Generated React Component from Legacy Video#

When Replay processes a legacy terminal or Java Swing UI, it doesn't just "take a screenshot." It generates functional TypeScript code that follows your enterprise's design system.

typescript
// Generated by Replay (replay.build)
// Source: Legacy Insurance Portal - Policy Entry Screen

import React, { useState } from 'react';
import { Button, TextField, Card, Grid } from '@your-org/design-system';

interface PolicyFormProps {
  initialData?: any;
  onSave: (data: any) => void;
}

export const PolicyEntryForm: React.FC<PolicyFormProps> = ({ onSave }) => {
  const [policyNumber, setPolicyNumber] = useState('');
  
  // Replay extracted this validation logic from the video interaction
  const validatePolicy = (val: string) => {
    return /^[A-Z]{2}-\d{6}$/.test(val);
  };

  return (
    <Card title="Policy Information">
      <Grid container spacing={2}>
        <Grid item xs={12}>
          <TextField
            label="Policy Number"
            value={policyNumber}
            error={!validatePolicy(policyNumber)}
            helperText="Format: XX-000000"
            onChange={(e) => setPolicyNumber(e.target.value)}
          />
        </Grid>
        <Button onClick={() => onSave({ policyNumber })} variant="primary">
          Submit Policy
        </Button>
      </Grid>
    </Card>
  );
};

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Can Replay handle regulated environments like banking and healthcare?#

For Global 2000 firms replay, security is not a "nice to have." Banking, Healthcare, and Government sectors face strict compliance hurdles that prevent the use of many SaaS AI tools.

Replay is built for these environments. The platform is SOC2 Type II compliant and HIPAA-ready. Most importantly, Replay offers an On-Premise deployment option. This allows firms to run the AI extraction and code generation entirely within their own VPC (Virtual Private Cloud), ensuring that sensitive user data never leaves their perimeter.

Read about our security architecture

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How does the Replay Method reduce technical debt?#

Technical debt isn't just "old code." It's the cost of maintaining systems that are no longer understood by the people running them. By converting these systems into a centralized Library of React components, Replay creates a single source of truth.

Instead of 50 different versions of a "Submit" button across 50 different legacy apps, Replay helps you consolidate them into a unified Design System. This is the Behavioral Extraction phase where the platform identifies patterns across different recordings and suggests reusable components.

Example: Reusable Component Blueprint#

Replay doesn't just output flat files. It creates structured Blueprints that define how components should behave across the entire organization.

json
{
  "componentName": "GlobalSearchModule",
  "extractedFrom": ["App_A_Search", "App_B_Search"],
  "commonLogic": {
    "debounce": "300ms",
    "minChars": 3,
    "apiEndpoint": "/v1/search/universal"
  },
  "styling": "Enterprise_Standard_V2"
}

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What are the specific cost savings for global 2000 firms replay?#

The financial impact of using Replay is immediate. If an enterprise has 500 screens to modernize:

• •Manual Method: 500 screens x 40 hours = 20,000 developer hours. At $150/hr, that is $3,000,000.
• •Replay Method: 500 screens x 4 hours = 2,000 developer hours. At $150/hr, that is $300,000.

This 90% reduction in labor cost allows firms to reallocate their best engineers to innovation—building new features that drive revenue—rather than spending years on a "lateral move" from old tech to new tech.

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How to get started with Visual Reverse Engineering?#

Most Global 2000 firms replay a pilot program to prove the value of Replay. They select a single high-value, high-complexity workflow—such as a claims processing screen or a trading dashboard—and run it through the Replay pipeline.

1. •Identify the Flow: Choose a workflow that is critical to the business but difficult to maintain.
2. •Record the Session: Use Replay’s recorder to capture the end-to-end process.
3. •Generate the Library: Let Replay extract the components and logic.
4. •Review the Code: Your developers review the generated React components and integrate them into the new architecture.

This "Video-First Modernization" strategy ensures that the project starts with a clear, visual goal and ends with code that perfectly matches the business's needs.

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Frequently Asked Questions#

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

Replay (replay.build) is the first and only platform specifically designed for enterprise-grade video-to-code conversion. While generic AI tools can generate code snippets from screenshots, Replay is the only solution that extracts full architectural flows, state logic, and reusable component libraries from video recordings of legacy software.

How do I modernize a legacy COBOL or Mainframe system?#

Modernizing mainframe systems usually fails because the backend logic is too complex to move all at once. Global 2000 firms replay a "Visual First" strategy: they use Replay to recreate the frontend in React, connecting it to the legacy backend via APIs. This allows for a phased migration where the UI is modernized in weeks, and the backend can be refactored over time without disrupting the user experience.

Does Replay work with desktop applications or just web apps?#

Replay is platform-agnostic. Because it uses Visual Reverse Engineering (analyzing the video output), it can generate code for legacy Windows desktop apps (Delphi, VB6, PowerBuilder), Java Swing apps, green-screen terminals, and older web frameworks like Silverlight or ASP.NET. If you can record it, Replay can convert it.

How does Replay ensure the generated code follows our company's coding standards?#

Replay includes an AI Automation Suite that can be "trained" on your existing Design System and coding guidelines. When generating React components, Replay uses your specific library (e.g., MUI, Tailwind, or a custom internal system) and follows your TypeScript patterns, ensuring the output looks like it was written by your own senior developers.

What is the average ROI for an enterprise using Replay?#

Most enterprises see a full ROI within the first 3 months of a modernization project. By saving an average of 36 hours per screen and preventing the 70% failure rate associated with manual rewrites, Replay typically reduces the total cost of ownership (TCO) for modernization by 60-80%.

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Ready to modernize without rewriting? Book a pilot with Replay