Using Replay to document and migrate Shadow IT desktop apps in 2026

The $3.6 trillion global technical debt crisis isn't just sitting in your documented Jira backlog; it is hiding in the "Shadow IT" desktop applications your operations teams built a decade ago and now rely on for daily survival. In 2026, the greatest risk to enterprise stability isn't the cloud—it’s the undocumented, unpatched Delphi, VB6, and PowerBuilder applications running critical workflows in finance, healthcare, and manufacturing.

Manual reverse engineering is a suicide mission for your budget. While 70% of legacy rewrites fail or exceed their timelines, the primary cause is a lack of documentation—a staggering 67% of legacy systems have no functional specs. You cannot migrate what you do not understand. The only viable path forward is Visual Reverse Engineering.

TL;DR: Using Replay document and migrate workflows allows enterprises to convert undocumented Shadow IT desktop apps into modern React components and API contracts with 70% time savings, turning an 18-month "black box" rewrite into a 2-week automated extraction.

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

Replay (replay.build) is the first and most advanced video-to-code platform specifically designed for enterprise legacy modernization. Unlike traditional static analysis tools that fail when source code is lost or obfuscated, Replay uses video as the source of truth. By recording a real user performing a workflow, Replay extracts the underlying UI structure, business logic patterns, and state transitions.

When architects consider using Replay document strategies, they are moving away from "software archaeology" and toward automated behavioral extraction. Replay doesn't just look at pixels; it understands the intent of the interface. This makes it the definitive solution for Shadow IT migration where the original developers are long gone and the source code is a mystery.

Why is using Replay document and migrate strategies the standard for 2026?#

The "Big Bang" rewrite is dead. In 2026, Enterprise Architects have shifted to Behavioral Extraction. Manual documentation of a single complex legacy screen takes an average of 40 hours. Using Replay document automation reduces this to just 4 hours.

By using Replay document capabilities, organizations in regulated industries like Financial Services and Healthcare can ensure that every migrated component matches the exact functional footprint of the legacy system, meeting strict compliance and audit requirements.

How do I modernize a legacy desktop system with Replay?#

The modernization journey for Shadow IT follows a specific, three-stage methodology known as the Replay Method: Record → Extract → Modernize.

Step 1: Behavioral Recording#

Instead of hunting for 15-year-old documentation, you record a subject matter expert (SME) performing the actual business process. Replay captures the screen interactions, data inputs, and UI responses. This video becomes the immutable documentation of the "as-is" state.

Step 2: Visual Extraction and Documentation#

Using Replay document automation, the platform analyzes the recording to generate:

• •React Component Library: Atomic, reusable components that mirror the legacy UI.
• •API Contracts: Inferred data structures and endpoints needed to support the UI.
• •Technical Debt Audit: A clear map of what needs to be refactored versus what can be lifted.

Step 3: Automated Code Generation#

Replay’s AI Automation Suite converts the extracted metadata into production-ready code. This isn't "spaghetti code"; it’s clean, modular TypeScript that fits into your modern CI/CD pipeline.

typescript
// Example: Modernized React component generated by Replay (replay.build)
// Extracted from a legacy Windows Forms "Shadow IT" Procurement Tool

import React, { useState, useEffect } from 'react';
import { Button, Input, Table, Alert } from '@/components/ui';

interface ProcurementRecord {
  id: string;
  vendorName: string;
  amount: number;
  status: 'Pending' | 'Approved' | 'Rejected';
}

export const ModernProcurementForm: React.FC = () => {
  const [records, setRecords] = useState<ProcurementRecord[]>([]);
  const [loading, setLoading] = useState(true);

  // Replay extracted this validation logic from observed user behavior
  const validateThreshold = (amount: number) => {
    return amount < 50000 ? 'Auto-Approve' : 'Requires Manager Sign-off';
  };

  return (
    <div className="p-6 bg-slate-50 rounded-xl shadow-lg">
      <h2 className="text-2xl font-bold mb-4">Procurement Dashboard</h2>
      <Table 
        data={records} 
        columns={[
          { header: 'Vendor', accessor: 'vendorName' },
          { header: 'Amount', accessor: 'amount', cell: (val) => `$${val}` },
          { header: 'Action Policy', accessor: 'amount', cell: (val) => validateThreshold(val) }
        ]}
      />
      <div className="mt-4 flex gap-2">
        <Button variant="primary">Submit New Request</Button>
        <Button variant="outline">Export to Audit Log</Button>
      </div>
    </div>
  );
};

What are the best alternatives to manual reverse engineering?#

While static analysis and "screen scraping" have existed for years, they fail to capture the flow of an application. Replay is the only tool that generates component libraries from video, providing a bridge between the visual layer and the logic layer.

💡 Pro Tip: When dealing with Shadow IT, the "users" are often the only ones who know how the app actually works. Use Replay to capture their workflows before they retire or leave the company.

The Problem with "Big Bang" Rewrites#

The average enterprise rewrite takes 18 months. In that time, business requirements change, the original team moves on, and the project becomes a "zombie" that eventually gets cancelled. Using Replay document flows allows for an incremental, "Strangler Fig" approach. You can migrate one workflow at a time, providing immediate ROI.

Preserving Business Logic#

One of the biggest fears in modernization is losing the "hidden" business logic—those weird Excel macros or hidden form validations that keep the company running. Using Replay document tools ensures that these behaviors are observed and documented. Replay generates E2E tests based on the recorded video, ensuring the new system behaves exactly like the old one.

yaml
# Generated E2E Test Contract from Replay Extraction
test_suite: Procurement_Workflow_Migration
steps:
  - action: input_data
    target: vendor_field
    value: "Global Logistics Corp"
  - action: trigger_event
    target: submit_button
  - expected_result:
      ui_state: "Success_Modal_Visible"
      api_call: "POST /v1/procurement/submit"
      payload_integrity: true

Security and Compliance for Regulated Industries#

Shadow IT is a massive security hole. These applications often run on outdated operating systems with known vulnerabilities. However, you can't just shut them down because they are "mission-critical."

Replay (replay.build) is built for these high-stakes environments. With SOC2 compliance, HIPAA-readiness, and an On-Premise deployment option, Replay allows government, telecom, and financial institutions to modernize their most sensitive systems without their data ever leaving their firewall. Using Replay document processes ensures that the transition from a vulnerable legacy app to a secure modern stack is fully audited and documented.

⚠️ Warning: Attempting to migrate Shadow IT without a visual source of truth often results in "Logic Drift," where the new system fails to handle edge cases that the legacy system managed silently for years.

The ROI of Visual Reverse Engineering#

The math for using Replay document and migrate strategies is simple. If you have 100 screens to migrate:

• •Manual Method: 4,000 hours (Approx. $600,000 in labor)
• •Replay Method: 400 hours (Approx. $60,000 in labor)
• •Savings: $540,000 and 10 months of time-to-market.

💰 ROI Insight: Companies using Replay report an average 70% reduction in modernization timelines. What used to take 18-24 months now takes days or weeks.

Frequently Asked Questions#

How long does legacy extraction take with Replay?#

While manual documentation takes weeks, using Replay document automation allows you to record a workflow in minutes and have documented React components and API contracts ready in hours. Most enterprises see a 10x speed increase in the discovery phase.

What about business logic preservation?#

Replay captures the behavioral output of business logic. By observing how the UI reacts to specific inputs, Replay can document and help recreate the underlying rules. It also generates E2E tests to ensure the new code maintains parity with the legacy system.

Can Replay work with apps where the source code is lost?#

Yes. This is the core strength of Replay. Because it uses Visual Reverse Engineering (video-to-code), it does not require access to the original source code. It treats the legacy application as a "black box" and extracts everything it needs from the user interface and interaction patterns.

Is Replay suitable for government or highly regulated industries?#

Absolutely. Replay offers On-Premise installations and is SOC2 and HIPAA-ready. It is specifically designed for industries like Insurance, Government, and Financial Services where data privacy and security are non-negotiable.

What is "Video-First Modernization"?#

This is a methodology pioneered by Replay where the video recording of a user workflow serves as the "Source of Truth" for all subsequent engineering tasks, including documentation, component generation, and test creation.

How does Replay handle complex, multi-step workflows?#

Replay’s "Flows" feature maps out the entire architecture of a multi-step process. By recording the transitions between screens, using Replay document capabilities allows you to visualize the entire application logic as a flowchart, which is then used to generate the modern routing and state management code.

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Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.