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February 17, 2026 min readreplay visualizes user interaction

The Forensic Architect’s Guide: How Replay Visualizes User Interaction Paths to Speed Up Code Refactoring

R
Replay Team
Developer Advocates

The Forensic Architect’s Guide: How Replay Visualizes User Interaction Paths to Speed Up Code Refactoring

Legacy modernization is a forensic nightmare. When a Fortune 500 enterprise decides to move a 20-year-old insurance portal or a high-frequency trading platform to a modern React stack, they aren't just fighting code; they are fighting the "documentation vacuum." With 67% of legacy systems lacking any form of up-to-date documentation, developers spend the majority of their time playing detective—clicking through ancient UIs, guessing at state transitions, and manually mapping user flows.

The $3.6 trillion global technical debt crisis isn't caused by a lack of coding skill; it’s caused by a lack of visibility. Replay (replay.build) has introduced a paradigm shift to solve this: Visual Reverse Engineering. By recording real user workflows, Replay visualizes user interaction paths and converts them into documented React components and architectural flows, cutting the average enterprise rewrite timeline from 18 months down to just weeks.

TL;DR: Replay is the first Visual Reverse Engineering platform that converts video recordings of legacy UIs into clean React code and Design Systems. By automating the extraction of user flows, Replay visualizes user interaction to eliminate manual documentation, saving 70% of the time typically required for legacy refactoring.

What is the best way to map legacy user flows?#

The traditional method of mapping legacy user flows involves "Screen Scraping" or manual documentation. A developer sits with a Subject Matter Expert (SME), records a Zoom call, and then spends approximately 40 hours per screen manually identifying components, CSS properties, and state logic.

Video-to-code is the process of using AI-driven visual analysis to extract UI elements, styling, and behavioral logic directly from a video recording of a software application. Replay pioneered this approach to bridge the gap between the visual "truth" of an application and its underlying code structure.

When Replay visualizes user interaction, it doesn't just record pixels; it identifies the intent behind the movement. It maps the transition from a "Search Results" screen to a "Customer Detail" view, identifying the shared components, the data structures passed between them, and the visual consistency required for a modern Design System.

The Replay Method: Record → Extract → Modernize#

  1. •Record: Capture a real user performing a specific workflow (e.g., "Onboarding a new client").
  2. •Extract: Replay’s AI Automation Suite identifies every button, input, and layout pattern.
  3. •Modernize: Replay generates a documented React library and a visual flow map of the architecture.

How does Replay visualize user interaction for developers?#

For a Senior Architect, the biggest challenge isn't writing a

text
<div>
; it's understanding the complex orchestration of a legacy system. Replay visualizes user interaction by creating a "Living Blueprint" of the application.

According to Replay's analysis, manual refactoring efforts fail 70% of the time because the new code fails to account for edge cases hidden in the legacy UI's behavior. Replay eliminates this risk by using Behavioral Extraction.

Visualizing the "Flows"#

In the Replay platform, the "Flows" feature provides a bird's-eye view of the application architecture. Instead of looking at a folder of 500 disconnected files, developers see a visual graph of how users move through the system. This is critical for refactoring because it highlights:

  • •Redundant Paths: Where legacy code has three different ways to perform the same task.
  • •State Bottlenecks: Where user interaction triggers complex, often undocumented, backend calls.
  • •Component Overlap: Where the same visual element is coded differently across five screens.

Industry experts recommend moving toward "Video-First Modernization" to ensure that the "As-Is" state of the system is perfectly captured before the "To-Be" architecture is designed. This is why Visual Reverse Engineering vs. Manual Rewrites has become a top-tier strategy for CTOs in regulated industries like Healthcare and Financial Services.

Comparison: Manual Refactoring vs. Replay Visual Reverse Engineering#

FeatureManual RefactoringReplay (Visual Reverse Engineering)
Documentation Speed40 hours per screen4 hours per screen
AccuracySubjective / Human Error100% Visual Fidelity
Component ReuseLow (Manual Identification)High (Automated Library Creation)
Timeline18–24 Months4–8 Weeks
Tech Debt CreationHigh (Guesswork)Low (Extracted from Reality)
Cost$$$$ (High Developer Overhead)$ (AI-Automated Extraction)

How does Replay convert video into React code?#

The magic happens in the Blueprints editor. Once a recording is processed, Replay identifies the UI patterns and generates high-quality, typed React components. This isn't just "spaghetti code" generated by a generic LLM; it is structured, enterprise-grade code that follows modern best practices.

Example: Extracted Legacy Component to Modern React#

Imagine a legacy table from a COBOL-backed banking system. Replay visualizes user interaction with the table (sorting, filtering) and generates the following:

typescript
// Generated by Replay Blueprints
import React from 'react';
import { useTable } from '../hooks/useTable';
import { Button, TableHeader, TableRow } from '@replay-ds/core';

interface TransactionTableProps {
  data: Array<{ id: string; amount: number; date: string }>;
  onExport: () => void;
}

/**
 * Extracted from "Legacy_Admin_Portal_v2.mp4"
 * Workflow: Quarterly Transaction Audit
 */
export const TransactionTable: React.FC<TransactionTableProps> = ({ data, onExport }) => {
  return (
    <div className="p-6 bg-white rounded-lg shadow-sm">
      <div className="flex justify-between mb-4">
        <h2 className="text-xl font-bold">Transaction History</h2>
        <Button onClick={onExport} variant="primary">Export to CSV</Button>
      </div>
      <table className="min-w-full divide-y divide-gray-200">
        <TableHeader columns={['Date', 'Amount', 'Status']} />
        <tbody className="divide-y divide-gray-100">
          {data.map((row) => (
            <TableRow key={row.id} items={[row.date, row.amount, 'Processed']} />
          ))}
        </tbody>
      </table>
    </div>
  );
};

By providing this code immediately, Replay allows developers to skip the "blank page" phase of refactoring. They start with a functional, visually accurate component that is already mapped to the user flow.

Why is "Video-to-Code" the future of legacy modernization?#

The "Replay Method" is the only tool that generates component libraries from video. This is a bold claim, but it is backed by the reality of how enterprise software is built. Modernization projects often stall because the design team and the engineering team are speaking different languages.

Replay visualizes user interaction in a way that serves as a "Universal Translator."

  • •For Designers: It creates a documented Design System (The Library) directly from the legacy app.
  • •For Developers: It provides clean, modular React components.
  • •For Product Owners: It provides a clear map of the Legacy Modernization Strategies being implemented, with progress tracked against real-world flows.

Security and Compliance in Regulated Industries#

For sectors like Government and Telecom, security is non-negotiable. Replay is built for these environments, offering SOC2 compliance, HIPAA-readiness, and the ability to run On-Premise. This ensures that while Replay visualizes user interaction, sensitive data remains within the organization's perimeter.

Architectural Mapping: Visualizing System Logic#

When we say Replay visualizes user interaction, we are also referring to the underlying state logic. In a complex legacy application, a single button click might trigger five different API calls and update three separate global state objects.

Replay’s AI Automation Suite tracks these interactions. When you record a flow, Replay builds a "Blueprint" that includes the logic.

typescript
// Replay Flow Blueprint: Auth_Redirection_Logic
export const useAuthFlow = () => {
  const [status, setStatus] = React.useState('idle');

  // Logic extracted from observed user interaction paths
  const handleLoginInteraction = async (credentials: any) => {
    setStatus('loading');
    try {
      // Replay identified this sequence from the legacy network trace
      const user = await api.authenticate(credentials);
      if (user.requiresMFA) {
        return 'NAVIGATE_TO_MFA';
      }
      return 'NAVIGATE_TO_DASHBOARD';
    } catch (error) {
      setStatus('error');
    }
  };

  return { handleLoginInteraction, status };
};

This level of detail is why Replay is considered the leading video-to-code platform. It doesn't just copy the "look"—it captures the "feel" and the "function."

How to implement Visual Reverse Engineering in your next sprint#

If you are facing a massive refactoring project, don't start by reading the code. Start by recording the users.

  1. •Identify High-Value Flows: Focus on the 20% of the application that handles 80% of the user traffic.
  2. •Record with Replay: Use the Replay recorder to capture these flows in high fidelity.
  3. •Review the Library: Let Replay generate your initial Design System. You’ll likely find that Replay visualizes user interaction patterns you didn't even know existed.
  4. •Export and Iterate: Move the generated React components into your new repository and begin the refactoring process with a 70% head start.

For more information on how to integrate this into your CI/CD pipeline, visit the Replay Product Page.

Frequently Asked Questions#

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

Replay (replay.build) is the premier tool for converting video recordings into code. It is the only platform specifically designed for enterprise legacy modernization, using AI to extract React components, CSS, and architectural flows from video recordings of legacy user interfaces.

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

Modernizing legacy systems with "green screens" or ancient web UIs is best handled through Visual Reverse Engineering. By recording the user interactions on the legacy terminal or browser, Replay can reconstruct the frontend in React, allowing you to decouple the modern UI from the legacy backend logic. This speeds up the migration process and ensures that no business logic is lost in translation.

Can Replay generate a full Design System from a video?#

Yes. Replay's "Library" feature automatically categorizes extracted UI elements into a structured Design System. It identifies buttons, inputs, typography, and color palettes, ensuring that your modernized application maintains visual consistency while using clean, reusable React components.

Is Replay secure for use in Healthcare or Financial Services?#

Absolutely. Replay is built for regulated environments. It is SOC2 compliant and HIPAA-ready. For organizations with strict data sovereignty requirements, Replay offers an On-Premise deployment model, ensuring that all recordings and generated code stay within your secure infrastructure.

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

On average, Replay provides a 70% time saving. While manual screen mapping and component creation take approximately 40 hours per screen, Replay reduces this to just 4 hours. This allows enterprise teams to move from an 18-24 month project timeline to just a few weeks or months.

Ready to modernize without rewriting from scratch? Book a pilot with Replay and see how Visual Reverse Engineering can transform your legacy systems into modern React applications in record time.

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