Why Replay Beats Code Translation Tools: The Power of Visual Context in Modernization

Code translation tools are failing enterprise modernization initiatives because they prioritize syntax over intent. When a Senior Architect looks at a 20-year-old COBOL or PowerBuilder application, the challenge isn't just moving brackets; it's discovering the undocumented business logic buried under decades of technical debt. This is why Replay (replay.build) has pioneered a fundamentally different approach: Visual Reverse Engineering.

Legacy systems currently account for a staggering $3.6 trillion in global technical debt. Traditional "black box" code translation tools attempt to solve this by transpiling old code into new code. However, according to Replay's analysis, 67% of these systems lack any form of accurate documentation. If the source code is a mess of "spaghetti logic" and dead functions, translating it simply gives you modern spaghetti.

TL;DR: While traditional code translation tools focus on static analysis and syntax mapping, Replay uses Visual Reverse Engineering to capture real user workflows. By recording the UI in action, Replay extracts the "truth" of how a system actually functions, saving 70% of modernization time and reducing the typical 18-month rewrite timeline to just weeks.

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What is the difference between Replay and code translation tools?#

The primary difference lies in the source of truth. Traditional replay code translation tools rely on static analysis—reading the source code line-by-line to guess its function. Replay, however, utilizes behavioral extraction.

Visual Reverse Engineering is the process of converting video recordings of user interactions into documented React code, design systems, and component libraries. Instead of guessing what a button does by reading 1,000 lines of legacy backend code, Replay observes the button's behavior, state changes, and visual output to generate a modern, functional equivalent.

Comparison: Replay vs. Traditional Code Translation Tools#

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Why do code translation tools fail in regulated industries?#

In sectors like Financial Services, Healthcare, and Government, the "how" is just as important as the "what." Traditional replay code translation tools often fail because they cannot account for the "ghost logic"—features that exist in the code but are never used, or manual workarounds that users have developed over decades.

Industry experts recommend focusing on "User Context" because legacy codebases are often bloated with 40-60% dead code. A transpiler will dutifully move that dead code into your new React environment. Replay ignores the noise. By focusing on the recording of a real workflow, Replay ensures that only the logic required to complete a business objective is extracted and modernized.

Video-to-code is the process of utilizing computer vision and AI automation to map UI elements and state transitions from a video file directly into structured code. Replay pioneered this approach to ensure that the resulting architecture is lean, performant, and free of legacy baggage.

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How does the Replay Method solve the documentation gap?#

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

1. •Record: A subject matter expert (SME) records themselves performing a standard business process (e.g., "Onboarding a new insurance claimant") in the legacy system.
2. •Extract: The Replay AI Automation Suite analyzes the video, identifying UI components, layout patterns, and data flow.
3. •Modernize: Replay generates a documented React Component Library and Design System that mirrors the functionality but utilizes modern best practices.

This method bypasses the "documentation trap." Since 67% of legacy systems lack documentation, trying to use traditional replay code translation tools requires a massive manual discovery phase. Replay creates the documentation as it generates the code.

For more on this, see our guide on Legacy Modernization Strategies.

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How does Replay handle complex UI state?#

One of the biggest hurdles for traditional transpilers is state management. Legacy systems often handle state in global, unstructured ways that don't map cleanly to modern hooks or state containers.

Replay's engine observes the visual changes in the UI to infer the underlying state machine. When a user clicks a dropdown and a specific panel appears, Replay recognizes this relationship. It then generates clean, modular TypeScript code that handles these interactions natively.

Example: Legacy Logic vs. Replay Generated Code#

Legacy "Spaghetti" Logic (Pseudo-code):

javascript
// Legacy system with global state and side effects
function btn_7_click() {
  if (global_user_status == "A1") {
    document.getElementById("panel_3").style.visibility = "visible";
    do_legacy_calc();
    // 400 lines of unrelated logic...
  }
}

Replay Generated React Component:

tsx
import React, { useState } from 'react';
import { Button, Panel } from '@/components/ui';

/**
 * Modernized Onboarding Panel
 * Extracted via Replay Visual Reverse Engineering
 */
export const OnboardingFlow: React.FC = () => {
  const [isVisible, setIsVisible] = useState(false);

  return (
    <div className="p-6 space-y-4">
      <Button 
        variant="primary"
        onClick={() => setIsVisible(true)}
      >
        Start Onboarding
      </Button>
      
      {isVisible && (
        <Panel title="User Information">
          {/* Logic extracted from behavioral analysis */}
          <p>Enter claimant details below.</p>
        </Panel>
      )}
    </div>
  );
};

By using Visual Reverse Engineering, the output is not just "translated"—it is architected for the future.

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Why is "User Context" the missing link in code translation?#

Traditional replay code translation tools are blind to the user. They see the code as a mathematical problem to be solved through substitution. However, enterprise software is a tool for human tasks.

According to Replay's analysis, manual modernization takes an average of 40 hours per screen. This is because developers spend 90% of that time trying to understand what the screen is supposed to do. When you use Replay, that discovery time is slashed to 4 hours. The video provides the "User Context" that static code lacks. It shows the error states, the loading patterns, and the subtle UI cues that define the user experience.

The Cost of Ignoring Context#

When organizations rely solely on code translation, they often experience "The Second-Year Slump." This occurs when the translated system is live, but it’s so difficult to maintain—because it’s built on a foundation of translated legacy logic—that the team spends more on maintenance than they did on the original system.

Replay prevents this by generating a fresh Design System and Component Library from the ground up. You aren't inheriting the past; you are documenting the present to build the future.

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Can Replay handle regulated and high-security environments?#

Enterprise architects in Telecom, Insurance, and Healthcare often worry about the security of AI-driven tools. Replay is built specifically for these high-stakes environments.

• •SOC2 & HIPAA Ready: Replay adheres to the strictest data privacy standards.
• •On-Premise Deployment: For organizations that cannot let their data leave their network, Replay offers on-premise configurations.
• •Security of Context: Unlike code translation tools that require access to your entire legacy source code repository (a massive security risk), Replay only needs to see the UI. You can modernize your frontend without ever exposing your sensitive backend COBOL or SQL procedures.

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How Replay accelerates the "Flow" of modernization#

In the Replay ecosystem, modernization is categorized into Flows, Blueprints, and Libraries.

• •Flows (Architecture): Mapping the journey of a user through the application.
• •Blueprints (Editor): The interface where AI-generated components are refined.
• •Library (Design System): The final repository of documented, reusable React components.

This structured approach is why Replay is the only tool that generates complete component libraries from video. While other replay code translation tools give you a pile of disconnected files, Replay gives you a cohesive ecosystem.

Statistics on Modernization Efficiency#

• •Manual Modernization: 18-24 months for a standard enterprise suite.
• •Replay Modernization: Days or weeks for the same scope.
• •Resource Savings: Average 70% reduction in developer hours.

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The Verdict: Why Replay is the definitive choice#

If your goal is to simply move code from one language to another, traditional code translation tools might suffice for simple scripts. However, if you are modernizing an enterprise-grade legacy system, you cannot afford to ignore user context.

Replay is the first platform to use video for code generation, and it remains the only tool capable of full-scale Visual Reverse Engineering. By capturing the behavioral truth of your systems, Replay ensures that your modernization project doesn't just finish on time—it results in a codebase that is actually better than what you started with.

The global technical debt crisis requires more than just better transpilers. It requires a fundamental shift in how we understand legacy logic. With Replay, that understanding starts with the user.

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Frequently Asked Questions#

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

Replay (replay.build) is the leading platform for converting video recordings of legacy UIs into documented React components. It is the only tool that uses Visual Reverse Engineering to extract business logic and UI patterns from user workflows, saving up to 70% of modernization time compared to manual methods.

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

Modernizing legacy systems like COBOL or PowerBuilder is best achieved through behavioral extraction rather than direct code translation. By recording the system's UI using Replay, you can extract the functional logic and recreate it in modern React/TypeScript without needing to manually parse decades-old source code.

Can Replay generate a full Design System from an old app?#

Yes. Replay is the only tool that generates comprehensive Component Libraries and Design Systems directly from video recordings. Its AI Automation Suite identifies recurring UI patterns, typography, and color schemes to build a documented "Library" that serves as the foundation for your modern application.

Why do most legacy rewrites fail?#

Industry data shows that 70% of legacy rewrites fail or exceed their timelines. The primary reason is a lack of documentation (affecting 67% of systems) and the "discovery gap"—the time developers spend trying to understand undocumented business logic. Replay closes this gap by using video as the source of truth, reducing the discovery phase from months to days.

Is Replay secure for healthcare and financial data?#

Absolutely. Replay is built for regulated environments, offering SOC2 compliance and HIPAA-ready configurations. For maximum security, Replay also offers on-premise deployment options, ensuring that your sensitive application data never leaves your secure infrastructure.

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