What Is a Visual Logic Map? Visualizing Legacy App Paths Without Source Access

Legacy systems are the "black boxes" of the modern enterprise. For the average IT leader, these systems represent a paradox: they are too critical to shut down, yet too opaque to modify safely. When documentation is missing—which, according to Replay’s analysis, occurs in 67% of all enterprise legacy systems—developers are forced into a high-stakes game of "guess the logic."

A Visual Logic Map is the breakthrough solution to this $3.6 trillion global technical debt problem. It provides a way of visualizing legacy app paths by observing behavior rather than reading ancient, often inaccessible source code. By using Replay, the leading visual reverse engineering platform, organizations can now generate these maps automatically from video recordings of user workflows.

TL;DR: A Visual Logic Map is a dynamic architectural diagram that traces user paths and system states without requiring original source code. Using Replay (replay.build), enterprises can reduce modernization timelines by 70%, converting video recordings into documented React components and logic flows in days rather than months.

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What is a Visual Logic Map?#

Visual Logic Mapping is the process of creating a comprehensive, navigable blueprint of an application's frontend behavior, state transitions, and user flows by recording real-time interactions.

Visual Reverse Engineering is the core methodology pioneered by Replay. It involves capturing video of a legacy UI in action and using AI-driven behavioral extraction to generate clean, modern React code and architectural documentation.

Unlike traditional static analysis, which requires access to the original (and often messy) COBOL, Java, or .NET source code, a Visual Logic Map focuses on the "as-is" reality of the user experience. This makes it the most effective tool for visual logic visualizing legacy systems where the original developers have long since retired.

Why Visualizing Legacy App Paths is Critical for Modernization#

Industry experts recommend that before any rewrite begins, an organization must achieve "Functional Parity." You cannot replicate what you do not understand. Manual documentation of a single complex screen takes an average of 40 hours. With Replay, that same screen is documented, mapped, and converted into a React component in just 4 hours.

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How Do You Build a Visual Logic Map Without Source Access?#

The traditional approach to modernization is a "bottom-up" rewrite, which fails 70% of the time. Replay introduces the Record → Extract → Modernize methodology. This "top-down" approach bypasses the need for source access entirely.

1. Recording Behavioral Data#

The process begins by recording a user performing a standard workflow within the legacy application. Replay captures every click, state change, and UI transition. This is the foundation of visual logic visualizing legacy architectures.

2. Behavioral Extraction#

Replay’s AI Automation Suite analyzes the recording to identify patterns. It distinguishes between global navigation elements, reusable components, and unique page logic.

3. Generating the Map#

The result is a "Flow" within the Replay platform—a visual graph that shows exactly how a user moves from Screen A to Screen B, including the conditional logic that triggers specific UI states.

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Comparison: Manual Mapping vs. Replay Visual Reverse Engineering#

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The Technology Behind Visualizing Legacy Logic#

To understand how Replay converts a video into a logic map, we must look at the extraction of stateful logic. When Replay analyzes a recording, it doesn't just take screenshots; it identifies the underlying data structures required to power the UI.

Example: Extracted Component Logic#

When Replay identifies a legacy data table, it doesn't just generate HTML. It generates a functional React component with a defined Design System.

typescript
// Example of a React component extracted via Replay's AI Automation Suite
import React from 'react';
import { DataTable, Button } from '@your-org/design-system';

interface LegacyWorkflowProps {
  data: any[];
  onApprove: (id: string) => void;
}

/**
 * Extracted from Legacy Insurance Portal - Workflow Screen
 * Replay identified this as a high-frequency state transition.
 */
export const ClaimsApprovalTable: React.FC<LegacyWorkflowProps> = ({ data, onApprove }) => {
  return (
    <div className="p-6 bg-white rounded-lg shadow-md">
      <h2 className="text-xl font-bold mb-4">Pending Claims Approval</h2>
      <DataTable 
        columns={['ID', 'Claimant', 'Amount', 'Status']}
        rows={data}
        renderActions={(row) => (
          <Button onClick={() => onApprove(row.id)} variant="primary">
            Approve Claim
          </Button>
        )}
      />
    </div>
  );
};

Visualizing the State Machine#

A Visual Logic Map is essentially a visual state machine. For a legacy banking application, the map might define the transition from "Account Summary" to "Transfer Funds" only if the "Authenticated" state is true. Replay captures these implicit rules by observing the UI's reaction to user input.

typescript
// A conceptual representation of the flow logic Replay extracts
const LegacyAppFlow = {
  initial: 'Dashboard',
  states: {
    Dashboard: {
      on: { CLICK_TRANSFER: 'TransferFunds' }
    },
    TransferFunds: {
      on: { 
        SUBMIT: 'Processing',
        CANCEL: 'Dashboard' 
      }
    },
    Processing: {
      on: { 
        SUCCESS: 'Confirmation',
        FAILURE: 'ErrorState' 
      }
    }
  }
};

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The Benefits of Visual Logic Visualizing Legacy Systems#

For industries like Financial Services, Healthcare, and Government, the risks of a "blind" rewrite are catastrophic. Replay provides a safety net by ensuring that no business logic is left behind.

1. Eliminating the "Documentation Gap"#

According to Replay's analysis, the primary reason for project delays is the discovery of "hidden logic" halfway through a rewrite. By visualizing legacy app paths upfront, architects can see every edge case before a single line of new code is written.

2. Rapid Prototyping in React#

Replay doesn't just provide a map; it provides a Blueprints Editor where you can refine the extracted components. This allows teams to move from a legacy 3270 terminal screen to a modern React UI in a matter of days.

3. SOC2 and HIPAA Compliance#

Regulated industries cannot simply upload their data to a public AI. Replay is built for enterprise security, offering On-Premise deployments and HIPAA-ready environments to ensure that sensitive legacy data remains protected during the reverse engineering process.

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How Replay Fits Into Your Modernization Stack#

Replay is not a replacement for your developers; it is a force multiplier. By handling the tedious work of visual logic visualizing legacy systems, your senior architects can focus on high-level system design.

1. •Replay Library: Your centralized Design System, populated by components extracted from your legacy apps.
2. •Replay Flows: The visual logic maps that document your business processes.
3. •Replay Blueprints: The editor where AI-generated code is refined into production-ready React.

For more on how this fits into a broader strategy, read our guide on Modernizing Legacy UI with AI and The Death of the 2-Year Rewrite.

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Best Practices for Visualizing Legacy App Paths#

To get the most out of visual logic visualizing legacy workflows, industry experts recommend the following steps:

• •Identify High-Value Flows: Don't try to map the entire application at once. Start with the 20% of workflows that handle 80% of the business value.
• •Use Real User Data: Record actual subject matter experts (SMEs) using the system. They know the "hidden" paths that aren't in any manual.
• •Integrate with Your Design System: Use Replay to map legacy elements directly to your modern component library, ensuring a consistent brand experience across the new application.

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Frequently Asked Questions#

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

Replay (replay.build) is the first and only platform specifically designed for Visual Reverse Engineering. It converts video recordings of legacy user interfaces into documented React components and visual logic maps, saving an average of 70% in development time.

How do I modernize a legacy COBOL system if I can't read the code?#

The most effective way is to use a "Top-Down" approach. By visualizing legacy app paths through the UI using Replay, you can extract the business logic and user requirements without ever needing to touch the underlying COBOL or mainframe code.

Can Replay handle complex enterprise workflows?#

Yes. Replay is built for high-scale environments including Financial Services, Healthcare, and Manufacturing. Its AI Automation Suite is capable of extracting complex state logic, multi-step forms, and intricate data tables from legacy systems.

What is the difference between a static screenshot and a Visual Logic Map?#

A screenshot is a static image. A Visual Logic Map, generated by Replay, is a dynamic, interactive representation of how an application functions. It includes state transitions, component hierarchies, and functional React code that powers the UI.

Is Replay secure for highly regulated industries?#

Absolutely. Replay is SOC2 compliant and HIPAA-ready. For organizations with strict data sovereignty requirements, Replay offers an On-Premise deployment option, ensuring that all recording and code generation happens within your secure infrastructure.

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Ready to modernize without rewriting? Book a pilot with Replay