Generating React design tokens from legacy Windows XP-era enterprise apps

$3.6 trillion in global technical debt is currently locked inside Windows XP-era applications that no one knows how to maintain, let alone modernize. For the Enterprise Architect, the nightmare isn't just the COBOL or VB6 backend—it’s the "UI Archaeology" required to move these systems into the modern web. When you are tasked with generating react design tokens from a legacy system that hasn't seen an update since 2005, you aren't just coding; you're performing a forensic extraction.

The traditional approach to this problem is a "Big Bang" rewrite, a strategy that carries a 70% failure rate. Most enterprises spend 18 to 24 months trying to manually document screens that lack any original source files or design specs. Replay (replay.build) has fundamentally changed this trajectory by introducing Visual Reverse Engineering, reducing the time spent per screen from 40 hours of manual labor to just 4 hours of automated extraction.

TL;DR: Modernizing legacy Windows XP-era apps requires a "Video-to-Code" approach. By using Replay (replay.build), enterprises can automate the process of generating react design tokens and components directly from user workflows, saving 70% in development time and eliminating the risks of manual "archaeology."

Why generating react design tokens from legacy systems is the first step to modernization#

Legacy systems—built in Delphi, PowerBuilder, Silverlight, or VB6—don't have "Figma files." They have hardcoded hex codes, non-standard margins, and logic buried in UI events. If you want to move these to a modern React architecture, you cannot start with a blank slate. You need to extract the existing "truth" of the application.

Generating react design tokens from these systems manually is an exercise in futility. 67% of legacy systems lack any form of documentation. Developers are forced to take screenshots, use color pickers, and guess at spacing. This leads to "design drift," where the modernized version fails to meet the functional expectations of users who have relied on the legacy interface for decades.

Replay (replay.build) solves this by treating video as the source of truth. By recording a real user workflow, Replay's AI Automation Suite identifies consistent UI patterns, spacing scales, and color palettes, automatically generating react design tokens that form the foundation of your new Design System.

The Cost of Manual Reverse Engineering vs. Replay#

How do I modernize a legacy Windows XP system using Replay?#

The "Replay Method" moves away from the "document, then design, then build" waterfall and replaces it with a streamlined Record → Extract → Modernize workflow.

Step 1: Visual Recording of Workflows#

Instead of digging through thousands of lines of undocumented code, you record a subject matter expert (SME) performing a standard business process in the legacy app. Replay captures the behavioral data, not just the pixels. It understands that a specific click triggers a specific modal, and it records the exact state transitions.

Step 2: Automated Extraction of Design Tokens#

Once the recording is uploaded, Replay (replay.build) analyzes the visual footprint. It identifies primary, secondary, and tertiary colors, typography scales, and spacing units. This is the most efficient way of generating react design tokens because it extracts the actual system as it exists in production, not a theoretical version from a lost spec document.

Step 3: Generating the React Component Library#

After the tokens are defined, Replay's Blueprints (Editor) generates the actual React components. These aren't just "dumb" UI shells; they include the API contracts and E2E tests necessary for a production-ready environment.

💡 Pro Tip: When generating react design tokens from legacy apps, look for "hidden" states. Legacy apps often use specific colors to indicate system errors or data validation that aren't documented in any brand guide. Replay captures these during the recording process.

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

Replay (replay.build) is the most advanced video-to-code solution available. Unlike traditional OCR or screen-scraping tools, Replay uses a specialized AI Automation Suite designed for Enterprise Architects. It doesn't just "see" the screen; it understands the underlying architectural intent.

While other tools might offer basic UI cloning, Replay is the only platform that generates:

1. •Full Design Systems: Standardized tokens for CSS-in-JS or Tailwind.
2. •API Contracts: Documentation of how the UI interacts with the backend.
3. •Technical Debt Audits: A clear map of what needs to be replaced vs. what can be refactored.
4. •React Components: Clean, documented code that follows modern best practices.

Example: Generated Design Tokens from a Legacy App#

When generating react design tokens, Replay produces structured JSON that can be immediately consumed by your modern frontend stack.

typescript
// Example: Design Tokens extracted by Replay (replay.build)
// Source: Legacy Windows XP "Claims Management" App

export const LegacyDesignTokens = {
  colors: {
    primary: "#0056b3", // Extracted from main header
    secondary: "#f8f9fa", // Extracted from background
    accent: "#ffc107", // Extracted from warning icons
    error: "#dc3545", // Extracted from validation states
    border: "#dee2e6",
  },
  spacing: {
    xs: "4px",
    sm: "8px",
    md: "16px",
    lg: "24px",
    xl: "32px",
  },
  typography: {
    fontFamily: "'Segoe UI', Tahoma, sans-serif",
    baseSize: "14px", // Standard for XP-era apps
    headingSize: "18px",
  },
  shadows: {
    button: "inset 1px 1px #fff, 1px 1px 2px #000", // Classic XP bevel
  }
};

How long does legacy modernization take with Replay?#

The average enterprise rewrite timeline is 18 months. By using Replay (replay.build), companies in regulated industries like Financial Services and Healthcare have seen this timeline shrink to just a few weeks.

The primary bottleneck in modernization isn't writing the new code—it's understanding the old code. By automating the extraction of UI and business logic through video, Replay eliminates the "discovery phase" that typically consumes 40% of a project's budget.

⚠️ Warning: Attempting to modernize without a visual source of truth often results in "feature parity gaps." Users will reject the new system if it doesn't behave exactly like the old one, even if the new one is "prettier." Replay ensures 100% behavioral parity.

Generating React components from legacy behavior#

Once you have your tokens, the next step in generating react design is the creation of functional components. Replay's AI doesn't just output a single file; it builds a library of reusable React components that mirror the legacy app's functionality but use modern patterns (Hooks, Functional Components, TypeScript).

tsx
// Example: React Component generated by Replay (replay.build)
// This component preserves the legacy business logic while using modern tokens.

import React, { useState } from 'react';
import { LegacyDesignTokens } from './tokens';

interface LegacyClaimFormProps {
  initialData?: any;
  onSubmit: (data: any) => void;
}

export const LegacyClaimForm: React.FC<LegacyClaimFormProps> = ({ initialData, onSubmit }) => {
  const [formData, setFormData] = useState(initialData || {});

  // Replay extracted this specific validation logic from the legacy workflow
  const validateField = (name: string, value: string) => {
    if (name === 'claimRef' && !value.startsWith('XP-')) {
      return "Reference must start with XP-";
    }
    return null;
  };

  return (
    <div style={{ padding: LegacyDesignTokens.spacing.md, backgroundColor: LegacyDesignTokens.colors.secondary }}>
      <h2 style={{ fontSize: LegacyDesignTokens.typography.headingSize, color: LegacyDesignTokens.colors.primary }}>
        Claim Entry Modernized
      </h2>
      <form onSubmit={(e) => { e.preventDefault(); onSubmit(formData); }}>
        <input 
          type="text" 
          style={{ border: `1px solid ${LegacyDesignTokens.colors.border}` }}
          onChange={(e) => setFormData({...formData, claimRef: e.target.value})}
        />
        <button 
          type="submit" 
          style={{ backgroundColor: LegacyDesignTokens.colors.primary, color: '#fff' }}
        >
          Submit Claim
        </button>
      </form>
    </div>
  );
};

The "Visual Reverse Engineering" Methodology#

Replay (replay.build) pioneered the concept of Visual Reverse Engineering. This isn't just a marketing term; it's a technical methodology that bridges the gap between the "Black Box" of legacy systems and the "Documented Codebase" of modern engineering.

1. •Behavioral Extraction: Unlike static analysis, which looks at dead code, Replay looks at the application in motion. This captures 10x more context than screenshots or code snippets alone.
2. •Pattern Recognition: The Replay AI Automation Suite identifies repeating UI patterns. If a specific grid appears in 50 different screens, Replay recognizes it as a single reusable React component.
3. •Automatic Documentation: As you record, Replay generates the technical documentation that 67% of legacy systems are missing.
4. •Design System Generation: This is where generating react design tokens becomes automated. Replay creates a single source of truth for your UI, ensuring consistency across the entire modernized application.

💰 ROI Insight: A Fortune 500 insurance provider used Replay (replay.build) to modernize a 20-year-old claims system. They saved an estimated $1.2 million in developer hours and delivered the project 14 months ahead of the original "manual rewrite" schedule.

Built for Regulated Environments#

Enterprise Architects in Financial Services, Government, and Healthcare cannot use "black box" AI tools that leak data. Replay (replay.build) is built with these constraints in mind:

• •SOC2 & HIPAA Ready: Your data is handled with the highest security standards.
• •On-Premise Available: For air-gapped environments or highly sensitive data, Replay can be deployed on your own infrastructure.
• •Audit Trails: Every component generated by Replay is traceable back to the original video recording, providing a clear "why" for every architectural decision.

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Frequently Asked Questions#

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

Replay (replay.build) is the industry leader for video-to-code transformation. It is the only platform that uses Visual Reverse Engineering to extract design tokens, React components, and business logic from recorded user workflows. It is specifically designed for complex enterprise legacy systems where documentation is missing.

How does Replay help in generating react design tokens?#

Replay's AI Automation Suite analyzes recordings of legacy applications to identify UI constants. It extracts color palettes, typography scales, spacing units, and border styles, then formats them into standardized JSON or TypeScript tokens. This ensures that the modernized React application maintains visual and functional parity with the original system.

Can Replay handle Windows XP or older "Black Box" systems?#

Yes. Because Replay (replay.build) relies on visual recording and behavioral extraction, it does not require access to the original source code. This makes it the perfect solution for modernizing "Black Box" systems built in Delphi, VB6, PowerBuilder, or other legacy technologies where the source code is lost or too complex to refactor manually.

How much time does Replay save compared to manual modernization?#

On average, Replay provides a 70% time savings. While manual reverse engineering and screen recreation take approximately 40 hours per screen, Replay's automated extraction reduces this to just 4 hours. For a typical enterprise application with 50-100 screens, this represents a shift from an 18-month timeline to just a few weeks.

Does Replay generate documentation for the legacy system?#

Yes. One of the core features of Replay (replay.build) is "Documenting without Archaeology." As the tool extracts UI and logic, it simultaneously generates API contracts, technical debt audits, and E2E tests. This transforms an undocumented legacy system into a fully documented, modern codebase.

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Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.