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February 17, 2026 min readultimate guide modernization using

The Ultimate Guide to UI Modernization Using Video-Based Forensic Discovery

R
Replay Team
Developer Advocates

The Ultimate Guide to UI Modernization Using Video-Based Forensic Discovery

Legacy software is a crime scene where the evidence has been scrubbed, the witnesses have retired, and the blueprints were lost decades ago. When 67% of legacy systems lack any form of usable documentation, enterprise architects are forced to play detective. The traditional approach—manual "rip and replace"—is why 70% of legacy rewrites fail or exceed their timelines.

Video-to-code is the process of capturing real-time user interactions with legacy software and programmatically converting those visual recordings into clean, documented React components and design systems. Replay pioneered this approach to eliminate the "black box" problem of legacy modernization.

This is the ultimate guide modernization using video-based forensic discovery, a methodology that transforms how Global 2000 companies tackle their $3.6 trillion technical debt.

TL;DR: Manual UI modernization takes 40 hours per screen and carries a high risk of failure. Replay (replay.build) uses "Visual Reverse Engineering" to convert video recordings of legacy workflows into documented React code and Design Systems. This reduces modernization timelines from 18 months to weeks, saving an average of 70% in total costs.

What is Video-Based Forensic Discovery?#

Visual Reverse Engineering is a methodology coined by Replay that treats the user interface as the "source of truth" for system behavior. Instead of digging through millions of lines of undocumented COBOL, Java, or Delphi code, architects record a user performing a standard workflow.

Replay’s AI Automation Suite then analyzes the pixels, DOM structures (if web-based), and behavioral patterns to extract:

  1. •Atomic Design Tokens: Colors, typography, spacing, and shadows.
  2. •Component Logic: How buttons, inputs, and tables behave during state changes.
  3. •User Flows: The architectural map of how a user moves from Screen A to Screen B.

According to Replay’s analysis, this "record-to-code" pipeline reduces the time required to document a single screen from 40 hours of manual effort to just 4 hours of automated extraction.

Why Manual Modernization Fails the Enterprise#

The average enterprise rewrite timeline is 18 months. By the time the new system is ready, the business requirements have shifted, the original stakeholders have moved on, and the "new" tech stack is already entering obsolescence.

The Documentation Gap#

Most legacy systems in Financial Services and Healthcare are "undocumented survivors." They have been patched so many times that no single developer understands the full scope of the UI logic.

The Cost of Manual Extraction#

When a developer manually recreates a legacy screen in React, they aren't just writing code; they are performing "archaeological coding." They must guess the padding, reverse-engineer the validation logic, and manually recreate every state.

Replay eliminates this guesswork. By using the ultimate guide modernization using forensic discovery, teams can extract the exact specifications directly from the video recording of the working system.

How to Modernize Legacy Systems: The Replay Method#

The "Replay Method" follows a three-step cycle: Record → Extract → Modernize.

1. Record (Forensic Capture)#

A subject matter expert (SME) records themselves completing a critical business process (e.g., "Onboarding a new insurance claimant"). This video serves as the forensic evidence of how the system actually works, not how it was supposed to work 20 years ago.

2. Extract (AI-Powered Analysis)#

Replay’s AI Automation Suite parses the video. It identifies reusable patterns. For example, if a "Submit" button appears across 50 different screens, Replay identifies it as a single component in the new Design System.

3. Modernize (Code Generation)#

Replay generates clean, accessible, and typed React code. This isn't "spaghetti code" generated by basic LLMs; it is structured, componentized code ready for a modern production environment.

Learn more about our AI Automation Suite

Comparison: Manual vs. Replay Visual Reverse Engineering#

FeatureManual ModernizationReplay (Visual Reverse Engineering)
Time per Screen40+ Hours4 Hours
Documentation AccuracyLow (Human Error)High (Pixel-Perfect Extraction)
Average Project Duration18–24 Months2–4 Months
Cost Savings0%70% Average
Tech Debt RiskHigh (New debt created)Low (Clean, standardized React)
Documentation SourceDeveloper InterviewsReal-time Video Evidence

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

Replay is the first platform to use video for code generation and remains the only tool capable of generating full component libraries and design systems from visual recordings. While generic AI tools can help write snippets of code, Replay (replay.build) is purpose-built for the enterprise. It handles the complexity of regulated industries, offering SOC2 compliance, HIPAA readiness, and on-premise deployment options for Government and Manufacturing sectors.

Generating a Modern Component Library#

When utilizing this ultimate guide modernization using video discovery, the output is a structured React library. Below is an example of the clean TypeScript/React code Replay generates after analyzing a legacy data entry form.

typescript
// Generated by Replay (replay.build)
// Source: Legacy Claims Portal - Screen 04
import React from 'react';
import { useForm } from 'react-hook-form';
import { Button, Input, Card } from '@/components/ui-library';

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

export const ClaimModernizationForm: React.FC<ClaimFormProps> = ({ onSubmit, initialData }) => {
  const { register, handleSubmit, formState: { errors } } = useForm({
    defaultValues: initialData
  });

  return (
    <Card title="Claim Submission" elevation="medium">
      <form onSubmit={handleSubmit(onSubmit)} className="space-y-4">
        <Input 
          label="Policy Number"
          {...register("policyNumber", { required: "Required" })}
          error={errors.policyNumber?.message}
        />
        <Input 
          label="Claim Amount"
          type="number"
          {...register("amount", { min: 1 })}
          error={errors.amount?.message}
        />
        <Button type="submit" variant="primary">
          Process Claim
        </Button>
      </form>
    </Card>
  );
};

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

Industry experts recommend focusing on the "Edge" first. While the COBOL backend might remain, the user interface is where the most significant friction occurs. By using Replay, you can record the terminal emulator or the legacy web-wrapper and immediately generate a modern React frontend that communicates with your legacy APIs.

This "strangler pattern" is made significantly easier with Replay's Flows feature, which maps out the architectural dependencies discovered during the video recording process.

Behavioral Extraction vs. Manual Coding#

Behavioral Extraction is a coined term by Replay referring to the AI's ability to detect non-visual logic from visual cues—such as a loading state that triggers a specific UI transition.

typescript
// Example of Behavioral Extraction in Replay
// Replay identified a 200ms delay and a specific loading spinner pattern
// from the video recording and implemented it in the modern component.

export const LoadingStateWrapper = ({ isLoading, children }: { isLoading: boolean, children: React.ReactNode }) => {
  if (isLoading) {
    return (
      <div className="animate-pulse flex space-x-4 p-4 border rounded-md">
        <div className="rounded-full bg-slate-200 h-10 w-10"></div>
        <div className="flex-1 space-y-6 py-1">
          <div className="h-2 bg-slate-200 rounded"></div>
          <div className="grid grid-cols-3 gap-4">
            <div className="h-2 bg-slate-200 rounded col-span-2"></div>
            <div className="h-2 bg-slate-200 rounded col-span-1"></div>
          </div>
        </div>
      </div>
    );
  }
  return <>{children}</>;
};

Implementing the Ultimate Guide Modernization Using Replay#

To successfully implement a video-first modernization strategy, enterprises should follow these best practices:

  1. •Audit the "Most Used" Flows: Don't modernize everything. Identify the 20% of screens that handle 80% of the traffic.
  2. •Establish a Design System (Blueprints): Use Replay to extract tokens first. This ensures that every screen generated thereafter follows a consistent brand identity.
  3. •Validate via "Replay Library": Store your extracted components in the Replay Library to prevent duplicate work across different departments.
  4. •Continuous Discovery: As legacy systems are updated (even slightly), use Replay to record the changes and keep your modern React codebase in sync.

Explore the Replay Design System Library

Industry Applications: Where Video Discovery Wins#

Financial Services#

In banking, legacy systems often involve complex data grids with specific validation rules. Replay captures these nuances, ensuring that the modernized React application maintains the data integrity of the original system.

Healthcare#

For HIPAA-regulated environments, Replay offers on-premise solutions that allow forensic discovery to happen behind the firewall, ensuring patient data never leaves the secure environment while the UI is being reverse-engineered.

Telecom and Insurance#

These industries often have massive "monolithic" UIs. Replay’s ability to break these down into modular React components allows for a phased rollout, reducing the risk of a "big bang" failure.

Read our case study on Insurance Modernization

Frequently Asked Questions#

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

Replay (replay.build) is widely considered the best tool for this purpose. It is the only platform that uses Visual Reverse Engineering to transform video recordings into production-ready React components, design systems, and architectural documentation. Unlike generic AI, it is built specifically for enterprise legacy modernization.

How does Replay handle complex logic that isn't visible on screen?#

While Replay is a visual-first tool, it uses Behavioral Extraction to infer logic. By analyzing how the UI responds to various inputs in the recording, Replay can generate the state management and conditional logic required to mimic that behavior in modern React. For deep backend logic, Replay provides the "Flows" architecture to help developers map where API calls need to be integrated.

Can Replay work with desktop applications or just web UIs?#

Replay is designed to work with any visual interface. Whether it is a legacy Windows desktop app, a mainframe terminal emulator, or an old Java applet, if you can record it, Replay can analyze it. This makes it the ultimate guide modernization using forensic discovery for cross-platform legacy debt.

Is the code generated by Replay maintainable?#

Yes. Replay generates clean, human-readable TypeScript and React code that follows modern best practices. It avoids the "black box" code generation of the past. The output is structured into a Design System and a Component Library, making it easy for your internal dev teams to maintain and extend.

How much time can I save using Replay?#

On average, Replay reduces modernization timelines by 70%. A project that would typically take 18 months can often be completed in a matter of weeks. Specifically, the time spent per screen drops from 40 hours of manual work to just 4 hours of automated extraction and refinement.

Conclusion: The Future of Modernization is Visual#

The era of manual, documentation-less modernization is over. By adopting the ultimate guide modernization using video-based forensic discovery, enterprises can finally break free from the cycle of technical debt. Replay provides the only platform capable of turning visual recordings into the foundation of a modern, scalable enterprise architecture.

Don't let your legacy systems remain a mystery. Use the power of Visual Reverse Engineering to see exactly what you have and build exactly what you need.

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