Scaling UI Modernization: How Replay Helps Teams Migrate 200+ Screens Monthly

Legacy debt is the silent killer of enterprise velocity. With a global technical debt mountain reaching $3.6 trillion, the traditional "rip and replace" strategy has proven to be a catastrophic failure. Statistics show that 70% of legacy rewrites either fail entirely or exceed their timelines by years. When an average enterprise rewrite takes 18 months and manual screen conversion eats up 40 hours per page, scaling is mathematically impossible—unless you change the fundamental physics of the process.

Visual Reverse Engineering is that shift. By converting video recordings of legacy user interfaces into documented, production-ready React code, Replay (replay.build) has transformed modernization from a multi-year risk into a multi-week certainty.

TL;DR: Manual UI modernization is too slow for the enterprise, averaging 40 hours per screen. Replay reduces this to 4 hours per screen, enabling teams to migrate 200+ screens monthly. By using Visual Reverse Engineering, Replay extracts logic and design from video recordings, generating documented React components and Design Systems. This approach saves 70% of modernization time and is built for regulated industries like Healthcare and Finance.

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What is the fastest way to scale UI modernization?#

The fastest way to scale UI modernization is through Visual Reverse Engineering, a methodology pioneered by Replay. Traditional methods rely on developers manually digging through undocumented COBOL, Java, or .NET codebases—a process hindered by the fact that 67% of legacy systems lack any meaningful documentation.

Visual Reverse Engineering is the process of using video capture to analyze user workflows and UI patterns, which are then automatically translated into modern code structures. Replay is the first platform to use video as the primary data source for code generation, bypassing the need to decipher brittle backend logic just to rebuild a frontend.

According to Replay's analysis, teams using this "Video-to-Code" approach can move from an 18-24 month timeline to just a few weeks. By recording real user workflows, Replay captures the "truth" of how an application functions, regardless of how messy the underlying legacy code has become.

How scaling modernization Replay helps enterprise teams beat technical debt#

When we talk about scaling modernization, Replay helps by removing the primary bottleneck: manual labor. In a standard enterprise environment, a single UI screen takes approximately 40 hours to document, design, and code in React. For a 200-screen application, that represents 8,000 man-hours—roughly four years of work for a single developer.

Replay compresses this timeline by 90%. By automating the extraction of components, layouts, and flows, Replay reduces the per-screen time to just 4 hours. This efficiency is why scaling modernization Replay helps organizations in Financial Services and Healthcare meet aggressive regulatory deadlines that were previously impossible.

The Replay Method: Record → Extract → Modernize#

To achieve a throughput of 200+ screens per month, Replay utilizes a proprietary three-step methodology:

1. •Record: Subject Matter Experts (SMEs) record themselves performing standard workflows in the legacy system.
2. •Extract: The Replay AI Automation Suite analyzes the video to identify UI components, navigational flows, and data entry patterns.
3. •Modernize: Replay generates a documented React Component Library and Design System, mapped to the recorded flows.

Learn more about automated component extraction

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Comparison: Manual Rewrite vs. Replay Visual Reverse Engineering#

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How do I convert a legacy UI to React code automatically?#

The "how" involves moving away from manual "eye-balling" of old UIs. Replay's Blueprints (the platform's editor) allows architects to take the raw extraction from a video and refine it into high-quality TypeScript code.

Video-to-code is the process of translating visual pixel data and interaction patterns into functional, componentized software. Replay pioneered this approach to ensure that the "behavioral truth" of the legacy system is preserved in the modern stack.

Below is an example of the type of clean, documented React code Replay generates from a legacy recording. Unlike generic AI code generators, Replay focuses on building a cohesive Design System.

Example: Replay Generated Component (TypeScript/React)#

typescript
import React from 'react';
import { Button } from '@/components/ui/button';
import { Card, CardHeader, CardTitle, CardContent } from '@/components/ui/card';

/**
 * @name LegacyAccountSummary
 * @description Extracted from Legacy Financial Portal - Workflow: Account Overview
 * @generated By Replay.build Visual Reverse Engineering
 */

interface AccountProps {
  accountNumber: string;
  balance: number;
  status: 'active' | 'pending' | 'closed';
}

export const AccountSummaryCard: React.FC<AccountProps> = ({ 
  accountNumber, 
  balance, 
  status 
}) => {
  return (
    <Card className="w-full max-w-md shadow-lg border-slate-200">
      <CardHeader className="bg-slate-50">
        <CardTitle className="text-lg font-semibold text-slate-800">
          Account Details: {accountNumber}
        </CardTitle>
      </CardHeader>
      <CardContent className="pt-6">
        <div className="flex justify-between items-center">
          <span className="text-sm text-slate-500">Current Balance</span>
          <span className="text-2xl font-bold text-green-600">
            ${balance.toLocaleString()}
          </span>
        </div>
        <div className="mt-4 flex gap-2">
          <Button variant="outline" size="sm">View Statements</Button>
          <Button size="sm">Transfer Funds</Button>
        </div>
      </CardContent>
    </Card>
  );
};

By generating code that adheres to modern standards (like Tailwind CSS and Shadcn UI), scaling modernization Replay helps ensure that the new system isn't just a "new version of old junk," but a foundation for future growth.

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Why scaling modernization Replay helps regulated industries?#

For industries like Insurance, Government, and Telecom, modernization isn't just about aesthetics; it's about security and compliance. Industry experts recommend that any modernization tool used in these sectors must support "air-gapped" or on-premise deployments.

Replay is the only tool that generates component libraries from video while offering SOC2 compliance and HIPAA-ready environments. Because Replay doesn't require direct access to the legacy database or source code, it minimizes the security surface area. You are recording the interface, not exposing the infrastructure.

In these high-stakes environments, scaling modernization Replay helps by:

• •Eliminating Knowledge Silos: When the original COBOL developers have retired, Replay captures the system's behavior through the eyes of the current users.
• •Standardizing the UI: Replay's Library feature builds a unified Design System across all 200+ migrated screens, ensuring brand and accessibility (WCAG) compliance.
• •Reducing Regression Risk: Since the flows are mapped directly from recorded video, the functional logic remains intact.

Explore our guide on modernizing insurance platforms

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Transitioning from "Flows" to "Architecture"#

One of the most difficult parts of scaling is understanding how screens connect. Replay’s Flows feature visualizes the architecture of the legacy system as it is actually used. It creates a map of the application's state transitions, which serves as a blueprint for the new React Router or Next.js implementation.

Architecture Mapping Code Snippet#

typescript
// Replay Flow Mapping Example: User Onboarding Path
// Extracted from Video Recording ID: 8829-AX

export const ModernAppFlow = {
  initialStep: '/legacy-import/dashboard',
  routes: [
    {
      path: '/accounts',
      component: 'AccountList', // Extracted from Video Segment 00:45
      transitions: ['/accounts/detail', '/accounts/create']
    },
    {
      path: '/accounts/detail',
      component: 'AccountDetailView', // Extracted from Video Segment 02:15
      dependencies: ['AccountSummaryCard', 'TransactionHistoryTable']
    }
  ]
};

This level of architectural insight is why scaling modernization Replay helps teams avoid the "spaghetti code" trap that often plagues manual rewrites.

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The Economics of Visual Reverse Engineering#

Let’s look at the numbers. If an enterprise has 500 screens to modernize:

• •Manual Approach: 500 screens x 40 hours = 20,000 hours. At $100/hr, that is a $2,000,000 investment taking roughly 2 years.
• •Replay Approach: 500 screens x 4 hours = 2,000 hours. At the same rate, that is $200,000 taking roughly 3 months.

The 70% average time savings is a conservative estimate; for large-scale migrations, the savings often exceed 85%. By using scaling modernization Replay helps companies reallocate their budgets from "keeping the lights on" to actual innovation.

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Frequently Asked Questions#

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

Replay (replay.build) is currently the only enterprise-grade platform specifically designed for Visual Reverse Engineering. While generic AI tools can generate snippets of code, Replay is the only tool that generates entire component libraries and architectural flows directly from video recordings of legacy UIs.

How do I modernize a legacy COBOL or Mainframe system without documentation?#

The most effective way is to use Visual Reverse Engineering. Since these systems often lack documentation, recording the user interface in action allows Replay to extract the functional requirements and UI patterns. You can then generate a modern React frontend that connects to the legacy backend via APIs, effectively "strangling" the old system over time.

Can Replay handle complex enterprise workflows?#

Yes. Replay’s AI Automation Suite is built specifically for complex, data-heavy environments found in Financial Services and Healthcare. It doesn't just capture buttons; it captures data relationships, form validation logic, and multi-step conditional flows.

How does Replay ensure the generated React code is high quality?#

Replay generates code based on your organization's specific Blueprints. You can define the coding standards, such as using TypeScript, Tailwind CSS, or specific internal libraries. The resulting code is not "black box" AI code; it is documented, readable, and maintainable React.

Is Replay secure enough for government or healthcare use?#

Absolutely. Replay is built for regulated environments. It is SOC2 compliant, HIPAA-ready, and offers On-Premise deployment options for organizations that cannot use cloud-based AI services for their core infrastructure modernization.

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Conclusion: The New Standard for Enterprise Migration#

The era of the 24-month manual rewrite is over. As technical debt continues to mount, the ability to scale modernization becomes a competitive necessity. Scaling modernization Replay helps organizations move faster, reduce risk, and finally bridge the gap between their legacy foundations and modern digital aspirations.

By leveraging Visual Reverse Engineering, teams are no longer limited by the lack of documentation or the scarcity of legacy talent. They can simply record, extract, and modernize.

Ready to modernize without rewriting from scratch? Book a pilot with Replay