Optimizing the Modernization Funnel: From Discovery to React Deployment in 90 Days

Legacy modernization is where enterprise budgets go to die. With $3.6 trillion in global technical debt looming over IT departments, the traditional "rip and replace" strategy has proven to be a catastrophic failure for most. Statistics show that 70% of legacy rewrites fail or significantly exceed their timelines, often stretching past the 18-month mark before a single line of production-ready code is delivered.

The bottleneck isn't a lack of talent; it's a lack of visibility. When 67% of legacy systems lack any form of updated documentation, developers are forced to perform "archaeological coding"—digging through layers of undocumented COBOL, Java Swing, or PowerBuilder logic just to understand how a button functions.

Optimizing modernization funnel from discovery to deployment requires a shift from manual manual reconstruction to automated visual reverse engineering. By leveraging Replay, enterprises are compressing the standard 18-month rewrite cycle into a 90-day sprint.

TL;DR:

• •The Problem: Manual modernization takes 40 hours per screen and has a 70% failure rate.
• •The Solution: Use Replay for Visual Reverse Engineering to convert UI recordings into React code.
• •The Result: 70% time savings, moving from discovery to deployment in 90 days instead of 18-24 months.
• •Key Phases: Discovery (Days 1-20), Extraction (Days 21-45), Refinement (Days 46-75), and Deployment (Days 76-90).

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The Anatomy of a Broken Funnel#

Traditional modernization follows a linear, high-friction path: Discovery -> Documentation -> Design -> Development -> QA. The "Discovery" phase alone often consumes six months as business analysts attempt to map workflows that haven't been touched by their original creators in a decade.

Optimizing modernization funnel from a state of stagnation to high-velocity delivery requires removing the documentation gap. Industry experts recommend moving away from static requirements and toward "living capture."

Visual Reverse Engineering is the process of recording real-time user interactions with a legacy application to automatically generate technical specifications, architectural maps, and functional code.

According to Replay’s analysis, the manual effort required to document and rebuild a single complex enterprise screen averages 40 hours. With Replay, this is reduced to 4 hours. This 10x improvement is the catalyst for the 90-day modernization timeline.

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Phase 1: Discovery and Workflow Mapping (Days 1-20)#

The first step in optimizing modernization funnel from the outset is capturing the "Source of Truth." In legacy systems, the source of truth isn't the code—it's the user's workflow.

Using Replay, subject matter experts (SMEs) simply record themselves performing standard business operations. Replay’s AI Automation Suite analyzes these recordings, identifying every input, state change, and API call.

Building the "Flows" Architecture#

In these first 20 days, the goal is to create a digital twin of the legacy application's logic. Replay’s "Flows" feature automatically maps the architecture of the recorded session. Instead of a developer guessing how a multi-step insurance claim form validates data, Replay provides a visual map of the state transitions.

Understanding Visual Reverse Engineering

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Phase 2: Automated Extraction and Componentization (Days 21-45)#

Once the workflows are captured, the transition from "video to code" begins. This is where the bulk of the 70% time savings is realized.

Video-to-code is the process of using computer vision and large language models (LLMs) to transform a visual recording of a user interface into functional, structured React components and CSS modules.

From Pixels to TypeScript#

Instead of a frontend engineer manually writing every

and styling it to match a 20-year-old Delphi application, Replay’s AI extracts the layout, typography, and functional logic.

Below is an example of the type of clean, modular TypeScript code Replay generates from a legacy UI recording:

typescript
// Generated via Replay AI Automation Suite
import React, { useState } from 'react';
import { Button, Input, Card } from '@/components/ui-library';

interface LegacyDataProps {
  initialValue: string;
  onUpdate: (value: string) => void;
}

/**
 * Component: LegacyClaimForm
 * Extracted from: ClaimsPortal_v4_Recording_01.mp4
 * Purpose: Handles legacy validation logic for policy numbers.
 */
export const LegacyClaimForm: React.FC<LegacyDataProps> = ({ initialValue, onUpdate }) => {
  const [value, setValue] = useState(initialValue);
  const [error, setError] = useState<string | null>(null);

  const validatePolicy = (val: string) => {
    // Logic reverse-engineered from legacy screen behavior
    const regex = /^[A-Z]{3}-\d{6}$/;
    if (!regex.test(val)) {
      setError("Invalid Policy Format (Expected: AAA-123456)");
      return false;
    }
    setError(null);
    return true;
  };

  const handleSubmit = () => {
    if (validatePolicy(value)) {
      onUpdate(value);
    }
  };

  return (
    <Card className="p-6 shadow-md border-legacy-blue">
      <h3 className="text-lg font-bold mb-4">Policy Information</h3>
      <Input 
        value={value} 
        onChange={(e) => setValue(e.target.value)}
        placeholder="AAA-123456"
        className={error ? 'border-red-500' : ''}
      />
      {error && <p className="text-sm text-red-500 mt-2">{error}</p>}
      <Button onClick={handleSubmit} className="mt-4 w-full">
        Update Record
      </Button>
    </Card>
  );
};

By optimizing modernization funnel from manual coding to AI-assisted extraction, the development team shifts their focus from "how to build it" to "how to improve it."

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Phase 3: Building the Design System and Refinement (Days 46-75)#

A common mistake in modernization is recreating the "ugliness" of the legacy system in React. Optimizing modernization funnel from a visual standpoint means abstracting the extracted components into a reusable Design System.

Replay’s "Library" feature acts as a centralized repository for these extracted components. As screens are processed, Replay identifies patterns. If it sees a "Submit" button in 50 different recordings, it suggests a single, standardized component for the new Design System.

Implementing a Modern Component Library#

During this phase, developers take the "Blueprints" (the raw extracted code) and wrap them in the organization's modern theme. This ensures that the 90-day deployment isn't just a functional clone, but a significant UX upgrade.

typescript
// Standardizing the extracted components into a Design System
import { styled } from '@stitches/react';

export const ModernButton = styled('button', {
  backgroundColor: '$primary600',
  borderRadius: '$md',
  padding: '10px 20px',
  color: 'white',
  '&:hover': {
    backgroundColor: '$primary700',
  },
  // Mapping legacy 'disabled' states to modern UI patterns
  '&:disabled': {
    backgroundColor: '$gray300',
    cursor: 'not-allowed',
  }
});

How to Build a Design System from Legacy UI

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Phase 4: Integration and Deployment (Days 76-90)#

The final stage of optimizing modernization funnel from development to production involves connecting the new React frontend to existing backend APIs or middleware.

Because Replay captures the network layer during the recording phase, the team already has a documented list of API endpoints, payload structures, and authentication headers. This eliminates the "integration hell" that usually occurs at the end of a project.

The SOC2 and HIPAA Advantage#

For industries like Financial Services and Healthcare, deployment isn't just about code; it's about compliance. Replay is built for regulated environments, offering SOC2 compliance and On-Premise deployment options. This ensures that even during the rapid 90-day funnel, data sovereignty is maintained.

According to Replay’s analysis, enterprises using automated visual reverse engineering see a 90% reduction in post-deployment bugs because the new system is built directly from the proven behaviors of the old one.

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Strategies for Optimizing Modernization Funnel From Discovery to Deployment#

To hit the 90-day mark, senior architects should follow these three strategic pillars:

1. •Prioritize by Workflow, Not by Screen: Don't try to modernize every screen at once. Use Replay to identify the "High-Value Flows"—the paths users take 80% of the time. Modernize those first to show immediate ROI.
2. •Automate the Documentation: Stop writing Confluence pages that no one reads. Use Replay’s visual captures as the living documentation. If a developer needs to know how the "Interest Rate Calculator" works, they should watch the Replay capture and look at the extracted logic.
3. •Parallelize Design and Dev: In a traditional funnel, design waits for discovery, and dev waits for design. By optimizing modernization funnel from the start with Replay, these tracks run in parallel. The extraction happens while the designers are still defining the new global theme.

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Frequently Asked Questions#

How does Replay handle highly complex, data-heavy legacy tables?#

Replay’s AI is specifically trained on enterprise UI patterns. It can identify complex data grids, nested headers, and even custom filtering logic within legacy applications. It exports these as structured React components (like TanStack Table) while preserving the original data-binding logic.

Can we modernize applications that are behind a secure firewall?#

Yes. Replay offers On-Premise and VPC deployment options. This allows your team to record and process legacy workflows without any data ever leaving your secure network. Replay is built for the "HIPAA-ready" and "SOC2" requirements of large-scale enterprise environments.

What happens if our legacy system has no API?#

This is a common hurdle when optimizing modernization funnel from older systems. Replay’s visual capture helps map the data requirements. While Replay generates the frontend, it also provides a clear "Data Map" that your backend team can use to build a modern API wrapper or use an RPA (Robotic Process Automation) layer to bridge the gap.

Does Replay work with mainframe-based green screens?#

Yes. As long as the application is accessible via a terminal emulator or web portal, Replay can record the session. The AI treats the visual output as the source, allowing it to translate terminal-based workflows into modern, reactive web components.

Is the code generated by Replay maintainable?#

Absolutely. Unlike "low-code" platforms that lock you into a proprietary vendor format, Replay outputs standard TypeScript and React code. The code follows modern best practices, including component modularity and clean prop definitions. Once exported, the code is 100% yours to own and maintain in your own Git repositories.

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The Path Forward#

The $3.6 trillion technical debt crisis isn't going away, but the way we approach it must change. The era of 24-month modernization projects is ending. By optimizing modernization funnel from discovery to deployment using visual reverse engineering, organizations can finally move at the speed of business.

Replay provides the bridge between the "as-is" legacy reality and the "to-be" React future. By automating the most tedious 70% of the process—documentation, extraction, and boilerplate coding—your senior engineers are freed to do what they do best: innovate.

Ready to modernize without rewriting? Book a pilot with Replay and see your legacy system transformed into a modern React library in days, not years.