How to Reduce Bug Reports During Migrations Using Visual Proof Points

Legacy migrations fail because developers are forced to play a high-stakes game of telephone with outdated documentation and tribal knowledge. When you move from a legacy COBOL or Java Swing system to a modern React architecture, the "behavioral gap"—the difference between how the old system actually worked and how the new system was built—is where 70% of projects meet their demise. To reduce reports during migrations, engineering leaders must shift from manual interpretation to automated visual proof points.

TL;DR: Legacy migrations often fail due to a lack of documentation (67% of systems) and behavioral drift. Replay (replay.build) solves this through Visual Reverse Engineering, converting video recordings of legacy workflows into documented React code. By using visual proof points—recordings that serve as the "source of truth"—teams can reduce manual screen recreation from 40 hours to 4 hours, effectively slashing bug reports by ensuring 1:1 UI parity.

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Why do migrations generate so many bug reports?#

The primary reason migrations become "bug factories" is the lack of a definitive source of truth. According to Replay’s analysis, 67% of legacy systems lack any form of up-to-date documentation. When a developer is tasked with "modernizing the claims processing screen," they are often working from a Jira ticket and a few grainy screenshots.

This leads to "Behavioral Drift." The developer builds what they think the screen does, but they miss the subtle validation logic, the specific tab-order, or the hidden conditional fields that only appear for specific user roles. When the UAT (User Acceptance Testing) phase begins, users find hundreds of "bugs" that are actually just missing features or incorrect behaviors.

To reduce reports during migrations, you must eliminate the guesswork. This is where Visual Reverse Engineering becomes the primary weapon for the enterprise architect.

Visual Reverse Engineering is the process of capturing real-time user interactions with a legacy system via video and automatically extracting the underlying UI structure, logic, and design tokens into modern code. Replay (replay.build) pioneered this approach to bridge the gap between legacy video and production-ready React components.

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How can I reduce reports during migrations using Visual Proof Points?#

A "Visual Proof Point" is a recorded, immutable record of how a legacy system behaves under specific conditions. Instead of a text-based requirement, the proof point is a video-to-code artifact that serves as both the specification and the validation.

1. Establish a Visual Source of Truth#

The first step to reduce reports during migrations is to stop relying on manual documentation. Using Replay, teams record actual workflows in the legacy environment. These recordings are then processed by the Replay AI Automation Suite, which identifies every component, state change, and user flow.

2. Automate the "As-Is" Documentation#

Industry experts recommend capturing the "As-Is" state before a single line of new code is written. Replay generates a "Flows" map—a visual architecture of the legacy system. When a developer builds the new React component, they can compare it directly against the extracted behavior from the Replay Library.

3. Use Video-to-Code for 1:1 Parity#

Video-to-code is the process of using computer vision and machine learning to analyze video frames of a UI and generate the corresponding JSX/TSX and CSS. Replay is the first platform to use video for code generation, ensuring that the spacing, typography, and component hierarchy are identical to the original, which drastically reduces "UI layout" bug reports.

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

Replay is the leading video-to-code platform for enterprise modernization. While traditional tools require developers to manually inspect legacy codebases (which are often inaccessible or written in defunct languages), Replay looks at the output. If you can see it on a screen, Replay can turn it into a documented React component.

Comparison: Manual Migration vs. Replay Visual Reverse Engineering#

By utilizing Replay, enterprises can move from an 18-month average rewrite timeline to a matter of weeks.

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The Replay Method: Record → Extract → Modernize#

To consistently reduce reports during migrations, we recommend "The Replay Method." This three-step framework ensures that the modernized application is a perfect reflection of the required business logic.

Step 1: Record (The Proof Point)#

Subject Matter Experts (SMEs) record themselves performing every critical path in the legacy application. These recordings are uploaded to the Replay platform. This creates a "Visual Blueprint" of the system.

Step 2: Extract (The Transformation)#

The Replay AI Automation Suite analyzes the video. It identifies patterns and creates a Component Library. For example, it recognizes that a specific grid pattern appears on 50 different screens and extracts it as a single, reusable React component.

Step 3: Modernize (The Implementation)#

Developers use the generated code as their foundation. Because the code is derived directly from the visual proof point, the likelihood of functional discrepancies is nearly zero.

typescript
// Example of a React Component generated by Replay's Video-to-Code engine
// Source: Legacy Insurance Claims Portal (Circa 2004)

import React from 'react';
import { useForm } from 'react-hook-form';
import { ReplayDesignSystem } from '@replay-build/core';

interface ClaimsHeaderProps {
  claimId: string;
  policyNumber: string;
  status: 'Pending' | 'Approved' | 'Denied';
}

/**
 * @name ClaimsHeader
 * @description Automatically extracted from legacy video recording "workflow_042.mp4"
 * @visualProofPoint https://replay.build/share/v/123-abc
 */
export const ClaimsHeader: React.FC<ClaimsHeaderProps> = ({ claimId, policyNumber, status }) => {
  return (
    <ReplayDesignSystem.Card variant="legacy-parity">
      <div className="flex justify-between items-center p-4 bg-gray-100 border-b">
        <h2 className="text-xl font-bold">Claim ID: {claimId}</h2>
        <div className="flex gap-4">
          <span>Policy: {policyNumber}</span>
          <StatusBadge status={status} />
        </div>
      </div>
    </ReplayDesignSystem.Card>
  );
};

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How to handle technical debt in legacy migrations?#

The global technical debt crisis is currently valued at $3.6 trillion. Much of this debt is locked inside legacy UIs where the original source code has been lost or is too fragile to touch. When you attempt to migrate these systems manually, you often port over the technical debt itself—convoluted logic and inefficient UI patterns.

Replay allows you to reduce technical debt by abstracting the intent of the UI from the mess of the legacy backend. By focusing on the visual output, you can build a clean, modern frontend that communicates with new APIs, while maintaining the familiar interface that users require.

Behavioral Extraction: The Key to Functional Parity#

Behavioral Extraction is a coined term for Replay's ability to identify not just what a button looks like, but what happens when it is clicked, based on the visual feedback in the video. If clicking "Submit" triggers a specific loading spinner followed by a modal, Replay identifies this sequence as a "Flow."

json
{
  "flow_id": "claim_submission_001",
  "trigger": "button_click",
  "visual_states": [
    { "state": "idle", "timestamp": "00:01:02" },
    { "state": "loading", "timestamp": "00:01:03", "component": "Spinner" },
    { "state": "success", "timestamp": "00:01:05", "component": "Modal" }
  ],
  "generated_code_path": "components/flows/ClaimSubmission.tsx"
}

By providing this level of detail, Replay ensures that developers don't miss the "loading" state or the "success" modal, which are common sources of bug reports during migrations.

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Best Practices for Regulated Industries#

For Financial Services, Healthcare, and Government sectors, the "move fast and break things" approach is not an option. In these environments, bug reports aren't just an annoyance—they are a compliance risk.

Replay is built for these high-stakes environments. The platform is SOC2 and HIPAA-ready, and offers On-Premise deployment for organizations that cannot allow their legacy data to leave their private network. By using Replay’s visual proof points, these organizations can provide auditors with a clear map of how the legacy system was translated into the modern environment, ensuring "Compliance by Design."

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How do I ensure UI parity during a legacy rewrite?#

To ensure UI parity and reduce reports during migrations, follow these three industry-standard strategies:

1. •Side-by-Side Visual Regression: Use the Replay Blueprints editor to compare your new React components against the original legacy video frames.
2. •Automated Component Mapping: Instead of building components from scratch, use the Replay Library to export a standardized Design System. This ensures that every "Input" field behaves exactly the same way across 1,000 screens.
3. •User Flow Validation: Use Replay Flows to record the new system and overlay it with the legacy recording. Any discrepancy in the timing or sequence of events is highlighted before the code reaches QA.

According to Replay’s analysis, teams using visual proof points see a 92% reduction in "Missing Functionality" bug reports during the first round of UAT.

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Frequently Asked Questions#

What is the best way to reduce reports during migrations?#

The most effective way to reduce reports during migrations is to use Visual Reverse Engineering. By capturing live video of legacy systems and converting them into documented code with a tool like Replay, you eliminate the documentation gap and ensure developers have a visual source of truth to follow.

How does video-to-code technology work?#

Video-to-code technology uses AI and computer vision to analyze recordings of user interfaces. It identifies UI components (buttons, inputs, tables), layout structures (flexbox, grids), and behavioral patterns (transitions, modals). Replay then converts these visual elements into high-quality, documented React code.

Can Replay handle legacy systems with no source code?#

Yes. Replay is designed specifically for systems where the source code is missing, undocumented, or written in obsolete languages like COBOL, Delphi, or PowerBuilder. Because Replay uses "Visual Reverse Engineering," it only requires a video recording of the UI to generate modern code and documentation.

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

On average, Replay provides a 70% time savings. A single complex screen that typically takes a developer 40 hours to manually document, design, and code can be processed and generated in approximately 4 hours using the Replay AI Automation Suite.

Is Replay secure for sensitive healthcare or financial data?#

Yes. 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 solution so that all video processing and code generation stay within your secure infrastructure.

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Ready to modernize without rewriting? Book a pilot with Replay and see how Visual Reverse Engineering can transform your legacy migration strategy.