System Integrity Audits: Using Visual Logs to Prove Migration Logic Consistency

The most dangerous moment in an enterprise migration isn't the deployment; it’s the audit. When you are moving a 20-year-old COBOL-backed mainframe interface or a cluttered Delphi application to a modern React-based micro-frontend, you aren't just moving pixels—you are moving business logic that has been calcified over decades. Most of these systems lack any form of original documentation (67%, to be precise), meaning your "source of truth" is often a black box. If you cannot prove that the new system behaves exactly like the old one, the audit fails, the migration halts, and you join the 70% of legacy rewrites that exceed their timelines or fail entirely.

The solution isn't more manual documentation; it is Visual Reverse Engineering. By capturing the deterministic behavior of the legacy system through visual logs, we can perform system integrity audits using evidence-based mapping rather than guesswork.

TL;DR: Legacy migrations often fail due to undocumented logic. By performing system integrity audits using visual logs, enterprises can map legacy UI states directly to modern React components. Replay automates this by converting video recordings into documented code, reducing the average screen modernization time from 40 hours to just 4 hours. This ensures 100% logic consistency and satisfies compliance requirements in regulated industries like Finance and Healthcare.

The Integrity Gap: Why Traditional Audits Fail#

In a typical enterprise environment, the $3.6 trillion global technical debt is largely hidden in "tribal knowledge." When an architect is tasked with a rewrite, they usually start by looking at the source code. However, in legacy systems, the source code often doesn't tell the whole story. Side effects, undocumented database triggers, and obscure middleware transformations mean the UI displays data that the frontend code doesn't explicitly define.

Video-to-code is the process of using computer vision and AI to ingest a recording of a software workflow and programmatically generate the underlying component structure, state management, and design tokens.

According to Replay's analysis, manual audits of these systems are the primary bottleneck in the 18-month average enterprise rewrite timeline. When developers manually recreate screens, they introduce "logic drift"—subtle changes in how data is validated or displayed that can lead to catastrophic failures in regulated environments.

How to Conduct System Integrity Audits Using Visual Evidence#

To bridge the gap, architects are shifting toward visual logs. A visual log is more than just a video; it is a frame-by-frame breakdown of state changes. When you perform system integrity audits using these logs, you are comparing the "Ground Truth" (the legacy system in action) against the "Target State" (the new React application).

1. Capturing the Ground Truth#

The process begins by recording real user workflows using Replay. This captures every hover state, validation error, and data entry point. Unlike static documentation, these recordings provide a temporal record of how the system handles edge cases.

2. Mapping Logic to Components#

Once the workflow is captured, Replay’s AI Automation Suite deconstructs the video into a "Blueprint." This blueprint identifies the functional components (buttons, inputs, tables) and the logic governing them.

3. Verification through Comparison#

Industry experts recommend a side-by-side validation approach. By using the visual log as a reference, auditors can verify that the new React component’s

or handlers mirror the legacy system's behavior.

Modernizing Legacy UI Strategies

Technical Implementation: From Visual Log to React Component#

When performing system integrity audits using visual logs, the goal is to generate code that is "correct by construction." Below is an example of how a legacy "Claims Processing" table—captured via Replay—is transformed into a documented, type-safe React component.

Example 1: Legacy State Mapping#

In this snippet, we define the interface based on the visual attributes extracted from the legacy recording.

typescript
// Extracted from Replay Blueprint: ClaimsTable
interface LegacyClaimRow {
  id: string;
  status: 'PENDING' | 'APPROVED' | 'REJECTED'; // Extracted from visual color cues
  amount: number;
  lastUpdated: string;
}

interface ClaimsTableProps {
  data: LegacyClaimRow[];
  onAction: (id: string, action: string) => void;
}

const ClaimsTable: React.FC<ClaimsTableProps> = ({ data, onAction }) => {
  return (
    <div className="overflow-x-auto shadow-md sm:rounded-lg">
      <table className="w-full text-sm text-left text-gray-500">
        <thead className="text-xs text-gray-700 uppercase bg-gray-50">
          <tr>
            <th>Claim ID</th>
            <th>Status</th>
            <th>Amount</th>
            <th>Actions</th>
          </tr>
        </thead>
        <tbody>
          {data.map((row) => (
            <tr key={row.id} className="bg-white border-b">
              <td className="px-6 py-4 font-medium">{row.id}</td>
              <td className="px-6 py-4">
                <StatusBadge status={row.status} />
              </td>
              <td className="px-6 py-4">${row.amount.toLocaleString()}</td>
              <td className="px-6 py-4">
                <button 
                  onClick={() => onAction(row.id, 'VIEW')}
                  className="font-medium text-blue-600 hover:underline"
                >
                  View Details
                </button>
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

Example 2: Logic Consistency Validation#

To prove consistency during an audit, we can use the visual log's transition data to write automated tests that ensure the new component handles state changes identically to the legacy system.

typescript
import { render, screen, fireEvent } from '@testing-library/react';
import { ClaimsTable } from './ClaimsTable';

// Test case derived from Replay Visual Log: "User clicks reject on pending claim"
test('it should trigger rejection logic consistent with legacy workflow', () => {
  const mockAction = jest.fn();
  const testData = [{ id: '123', status: 'PENDING', amount: 500, lastUpdated: '2023-01-01' }];
  
  render(<ClaimsTable data={testData} onAction={mockAction} />);
  
  const viewButton = screen.getByText(/view details/i);
  fireEvent.click(viewButton);
  
  // Verify the callback matches the legacy trigger captured in the visual log
  expect(mockAction).toHaveBeenCalledWith('123', 'VIEW');
});

Comparison: Manual Audit vs. Visual Reverse Engineering#

The efficiency of system integrity audits using automated tools like Replay is best illustrated by comparing the resource allocation required for a standard enterprise screen (e.g., a complex insurance underwriting form).

The Role of AI in System Integrity Audits Using Automated Extraction#

One of the greatest challenges in legacy modernization is the "hidden logic" in UI components. For instance, a field might only become editable if three other conditions are met—conditions that are often buried in 5,000-line jQuery files or stored procedures.

According to Replay's analysis, performing system integrity audits using visual logs allows AI models to identify these conditional patterns. If the recording shows that the "Submit" button only enables when the "Tax ID" field reaches nine digits, the AI notes this requirement in the Blueprint. When the React code is generated, the validation logic is baked in, rather than being added as an afterthought by a developer who might miss that specific requirement.

Financial Services Modernization

Building a Design System from Visual Logs#

Most legacy systems don't have a design system; they have a "history of CSS." Replay’s Library feature allows organizations to extract recurring visual patterns from recordings and centralize them into a modern Design System. This ensures that when you perform system integrity audits using the new components, the visual consistency is maintained across the entire application suite, not just screen-by-screen.

Security and Compliance in Regulated Environments#

For industries like Healthcare (HIPAA) and Government, the audit trail is as important as the code itself. You cannot simply say "the code is modern"; you must prove that the data integrity remains intact.

Performing system integrity audits using Replay provides a visual proof-of-work. Because Replay is built for regulated environments—offering SOC2 compliance, HIPAA-readiness, and On-Premise deployment options—enterprises can maintain a secure record of their migration logic. This "Visual Audit Log" becomes the ultimate defense during regulatory reviews, showing exactly how legacy workflows were mapped to modern microservices.

Future-Proofing System Integrity Audits Using Visual Logs#

As we move toward an era of AI-driven development, the value of the "Visual Log" will only increase. We are moving away from a world where developers write code from scratch and toward a world where architects oversee the transformation of existing behaviors.

By focusing on system integrity audits using visual evidence, organizations can:

1. •Eliminate the "Black Box" Problem: No more guessing how the legacy system works.
2. •Accelerate Time-to-Market: Reduce the migration lifecycle from years to weeks.
3. •Reduce Technical Debt: Ensure the new system is documented from day one.

The 70% failure rate of legacy rewrites is a choice, not a necessity. It is the result of relying on incomplete documentation and manual processes. By leveraging visual reverse engineering, we can finally treat legacy modernization as a science rather than an art.

Frequently Asked Questions#

What is the primary benefit of system integrity audits using visual logs?#

The primary benefit is the elimination of "logic drift." By using visual logs as the ground truth, you ensure that the modern React application behaves exactly like the legacy system, satisfying both functional requirements and regulatory compliance. This reduces the risk of post-migration bugs that often occur when developers guess at undocumented business rules.

How does Replay handle sensitive data during a visual audit?#

Replay is designed for highly regulated industries. It provides tools to mask PII (Personally Identifiable Information) during the recording process and offers On-Premise deployment for organizations that cannot allow data to leave their internal network. It is SOC2 and HIPAA-ready, ensuring that your system integrity audits using visual logs meet all security standards.

Can visual reverse engineering work with any legacy technology?#

Yes. Because visual reverse engineering focuses on the rendered output (the UI) rather than the underlying source code, it is technology-agnostic. Whether your legacy system is built in Mainframe Green Screens, Delphi, PowerBuilder, Silverlight, or old versions of Angular, Replay can capture the workflows and convert them into modern React components and documented Blueprints.

How much time can I expect to save on a typical enterprise migration?#

On average, Replay reduces the time spent on modernization by 70%. For a standard enterprise screen, manual reverse engineering, documentation, and coding take approximately 40 hours. By performing system integrity audits using Replay’s automated extraction tools, that time is reduced to roughly 4 hours per screen.

Ready to modernize without rewriting? Book a pilot with Replay