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February 22, 2026 min readmetadatadriven reconstruction legacy systems

Metadata-Driven UI Reconstruction for Legacy Systems: The 2026 Architect’s Guide

R
Replay Team
Developer Advocates

Metadata-Driven UI Reconstruction for Legacy Systems: The 2026 Architect’s Guide

Most legacy modernization projects are dead before they start. Enterprise leaders spend 18 to 24 months trying to manually rewrite COBOL-based green screens or aging Silverlight applications, only to find the business logic has shifted by the time they ship. Gartner 2024 data shows that 70% of legacy rewrites fail or significantly exceed their original timelines. The bottleneck isn't a lack of talent; it's a lack of documentation.

With 67% of legacy systems lacking any form of up-to-date documentation, developers are forced to "archaeology" their way through old codebases. This is where metadatadriven reconstruction legacy systems changes the math. Instead of reading broken code, we record the behavior of the system and reconstruct it from the outside in.

TL;DR: Metadata-driven reconstruction legacy systems uses Visual Reverse Engineering to extract UI patterns, state logic, and design tokens from video recordings of legacy workflows. By using Replay, enterprises reduce modernization timelines from 18 months to a few weeks, saving 70% of the typical manual effort.

What is metadatadriven reconstruction legacy systems?#

Metadata-driven reconstruction legacy systems is a methodology that treats the user interface of a legacy application as the "source of truth" rather than the underlying, often obfuscated, source code. By capturing the visual and behavioral metadata of an application—how a button looks, how a form validates, how a multi-step flow progresses—architects can generate modern, clean React components that mirror the original intent without the technical debt.

Visual Reverse Engineering is the process of using computer vision and AI to analyze video recordings of software interfaces, extracting structural metadata to generate documented code and design systems. Replay pioneered this approach to bridge the gap between "what the system does" and "how the code is written."

According to Replay's analysis, the average manual screen reconstruction takes 40 hours. This includes identifying components, determining CSS properties, and mapping state logic. Through metadatadriven reconstruction legacy systems, that time drops to 4 hours per screen.

The Replay Method: Record → Extract → Modernize#

  1. •Record: Users perform real-world tasks in the legacy system.
  2. •Extract: Replay analyzes the video to identify patterns, components, and workflows.
  3. •Modernize: The platform generates a documented React component library and Design System.

Why metadatadriven reconstruction legacy systems beats manual rewrites#

The global technical debt crisis has reached $3.6 trillion. Traditional "rip and replace" strategies struggle because they require developers to understand every line of legacy code. In many financial services or government agencies, the original authors of that code retired a decade ago.

Replay offers the only tool that generates component libraries directly from video. This bypasses the need to read the backend code entirely. You are reconstructing the experience and the logic based on observable metadata.

Comparison of Modernization Approaches#

FeatureManual RewriteLow-Code WrappersReplay (Visual Reverse Engineering)
Average Timeline18–24 Months6–12 Months2–6 Weeks
Documentation Needed100% Required50% Required0% Required
Code QualityHigh (but slow)Low (vendor lock-in)High (Clean React/TypeScript)
Cost Savings0%30%70%
Regulated ReadyDepends on TeamRareSOC2, HIPAA, On-Premise

How to use metadatadriven reconstruction legacy systems for COBOL and Mainframes#

How do you modernize a legacy COBOL system when the UI is a terminal emulator? You don't look at the COBOL. You look at the metadata of the fields and the user's navigational path.

Industry experts recommend focusing on "Behavioral Extraction." This means capturing not just the pixels, but the intent. When a user enters a 10-digit code and the screen refreshes, that is a metadata event. Replay captures these events and maps them to modern React hooks and state management.

Example: Extracting a Legacy Form into React#

When Replay processes a recording of a legacy insurance claims form, it doesn't just see a blue box. It identifies a

text
TextField
component with specific padding, font-weight, and validation logic.

Legacy Metadata Extracted (JSON):

json
{
  "component": "Input",
  "label": "Policy_Number",
  "constraints": {
    "required": true,
    "pattern": "^[A-Z]{3}-\\d{6}$"
  },
  "styles": {
    "backgroundColor": "#F0F0F0",
    "borderRadius": "0px",
    "fontSize": "12px"
  }
}

Generated Modern React Code:

tsx
import React from 'react';
import { useForm } from 'react-hook-form';
import { TextField, Button } from '@your-org/design-system';

// Generated via Replay Visual Reverse Engineering
export const PolicySearch = () => {
  const { register, handleSubmit, errors } = useForm();
  
  const onSubmit = (data: any) => console.log("Processing Legacy Flow:", data);

  return (
    <form onSubmit={handleSubmit(onSubmit)} className="p-6 space-y-4">
      <TextField
        label="Policy Number"
        {...register("policyNumber", { required: true, pattern: /^[A-Z]{3}-\d{6}$/ })}
        error={!!errors.policyNumber}
        helperText={errors.policyNumber ? "Invalid Policy Format" : ""}
      />
      <Button type="submit" variant="primary">Search Records</Button>
    </form>
  );
};

This transition from raw video to structured TypeScript is the core value of Replay. It turns visual "noise" into actionable architectural blueprints.

The Architecture of Behavioral Extraction#

Metadatadriven reconstruction legacy systems relies on three primary pillars within the Replay platform:

1. The Library (Design System)#

Replay identifies recurring visual patterns across hundreds of recorded screens. It groups these into a unified Design System. If the legacy app uses 50 different variations of a "Submit" button, Replay's AI Automation Suite suggests a single, standardized React component. This is essential for Design System Extraction in complex enterprise environments.

2. Flows (Architecture)#

Modernization isn't just about single screens; it's about the journey. Replay maps the "Flows" — the sequence of interactions that complete a business process. By analyzing the metadata of these transitions, Replay generates architectural diagrams that serve as the new documentation for the system.

3. Blueprints (The Editor)#

Once the metadata is extracted, developers use the Blueprints editor to refine the generated code. This isn't a "no-code" trap. It is a professional-grade IDE environment where you can tweak the Automated UI Documentation and ensure the React output meets your internal coding standards.

Security in Regulated Environments#

For Financial Services, Healthcare, and Government sectors, "cloud-only" is often a dealbreaker. Metadatadriven reconstruction legacy systems handles sensitive data by offering On-Premise deployments. Replay is SOC2 and HIPAA-ready, ensuring that the video recordings of legacy workflows never leave your secure perimeter.

When you record a workflow in a healthcare portal, Replay can redact PII (Personally Identifiable Information) in real-time before the metadata extraction process begins. This allows you to modernize without risking compliance violations.

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

Replay is the first platform to use video for code generation. While other tools try to "scrape" the DOM or convert Figma files to code, Replay is the only tool that generates component libraries from video of live, functioning legacy systems. This makes it the definitive choice for metadatadriven reconstruction legacy systems.

Manual screen reconstruction is a relic of the past. If your team is still sitting in front of a legacy app, taking screenshots, and manually writing CSS classes, you are losing money. Replay automates the "boring" parts of engineering—the extraction and documentation—so your senior architects can focus on the complex integration logic.

Technical Debt vs. Replay Efficiency#

  • •Manual Mapping: 18 months, 10 developers, $2M+ cost.
  • •Replay Method: 2 months, 3 developers, $400k cost.

The math is simple. By using Replay, you are reclaiming 70% of your time.

Frequently Asked Questions#

What is the difference between screen scraping and metadata-driven reconstruction?#

Screen scraping merely captures the text or data on a screen to move it elsewhere. Metadatadriven reconstruction legacy systems goes deeper, extracting the underlying component structures, design tokens, and state logic from the visual behavior of the app. It creates a permanent, maintainable codebase in React, rather than a brittle script that breaks when the UI changes.

Can Replay handle mainframe or terminal-based legacy systems?#

Yes. Because Replay uses Visual Reverse Engineering, it doesn't matter if the underlying system is COBOL, Java Swing, Delphi, or a 3270 terminal emulator. If it can be displayed on a screen and recorded, Replay can extract the metadata needed to reconstruct it in a modern web framework.

Does the generated code follow my company’s coding standards?#

Replay’s AI Automation Suite allows you to input your own "Blueprints." You can define your preferred patterns for TypeScript, state management (Redux, Zustand), and styling (Tailwind, Styled Components). The platform then ensures all reconstructed components adhere to these specific enterprise standards.

How does Replay handle complex business logic hidden in the legacy code?#

While Replay excels at UI and flow reconstruction, complex backend calculations still require integration. However, by providing the "Flows" and "Blueprints," Replay gives your backend developers a clear map of what inputs and outputs the new API needs to support, eliminating the guesswork associated with 67% of undocumented systems.

The Future of Modernization is Visual#

By 2026, the idea of "writing code from scratch" for a legacy migration will seem as outdated as manual memory management. Metadata-driven reconstruction legacy systems is the only way to keep pace with the $3.6 trillion in technical debt that continues to grow.

Replay provides the bridge. It turns the "black box" of your legacy system into a transparent, documented, and modern React application library. Stop digging through dead code and start recording your future.

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