The Death of the Documentation Workshop: Capturing Intent via Video

The most expensive room in your enterprise is the conference room where ten $200/hour engineers sit for six weeks trying to remember how a legacy claims processing system works. This is the documentation workshop—a ritual of archaeological guesswork that costs millions and produces nothing but stale Confluence pages and outdated diagrams.

Documentation workshops are where modernization projects go to die. We spend months interviewing retirees and reading COBOL or jQuery spaghetti, trying to reconstruct "intent." Meanwhile, the $3.6 trillion global technical debt mountain continues to grow. The reality is that 67% of legacy systems lack any meaningful documentation, and the original authors are long gone.

The era of manual archaeology is over. The future isn't rewriting from scratch—it's understanding what you already have through visual reverse engineering.

TL;DR: Visual reverse engineering via Replay replaces months of manual documentation workshops with automated video-to-code extraction, reducing modernization timelines from years to weeks.

The Failure of the "Big Bang" Rewrite#

The industry standard for modernization is the "Big Bang" rewrite. You freeze features for 18 months, hire a small army of consultants, and attempt to replicate a decade of business logic in a modern stack.

It almost never works. Statistics show that 70% of legacy rewrites fail or significantly exceed their timelines. Why? Because you cannot migrate what you do not understand. When you lack documentation, you miss the "edge cases" that represent 80% of your actual business value.

The Cost of Manual Extraction#

When an Enterprise Architect attempts to manually document a single legacy screen—mapping inputs, validation logic, API calls, and state changes—it takes an average of 40 hours. In a system with 200 screens, that’s 8,000 man-hours before a single line of modern code is written.

Capturing Intent via Video: The New Source of Truth#

At Replay, we advocate for a different source of truth: the user's workflow. If a user can perform a task in the legacy system, the "intent" is visible. By recording real user workflows, we can reverse engineer the underlying architecture without ever opening a dusty PDF from 2008.

Visual reverse engineering allows us to move from a "black box" to a documented codebase in days. We use the video as the primary artifact to generate:

1. •React Components: Clean, modular UI code that mirrors legacy behavior.
2. •API Contracts: Definitions of exactly what data is moving between the front and back end.
3. •E2E Tests: Automated tests that ensure the modern version matches the legacy output.
4. •Technical Debt Audits: Identification of redundant logic and dead code paths.

💰 ROI Insight: Replacing manual discovery with Replay-driven extraction reduces the cost per screen from roughly $6,000 (manual) to $600 (automated).

Technical Deep Dive: From Video to React#

When we talk about "extracting" a component, we aren't just taking a screenshot. Replay analyzes the DOM mutations, network requests, and state transitions during a recorded session.

Consider a legacy insurance form. Instead of manually mapping 50 fields, Replay captures the interaction and generates a clean React component.

typescript
// Example: Generated component from Replay video extraction
// Source: Legacy Claims Portal (v2.4)
// Extraction Date: 2023-10-24

import React, { useState, useEffect } from 'react';
import { TextField, Button, Grid, Alert } from '@enterprise-ui/core';
import { validateClaimId, submitClaimUpdate } from './api-bridge';

interface ClaimFormProps {
  initialData: any;
  onSuccess: (data: any) => void;
}

export const ModernizedClaimForm: React.FC<ClaimFormProps> = ({ initialData, onSuccess }) => {
  const [formData, setFormData] = useState(initialData);
  const [errors, setErrors] = useState<string[]>([]);

  // Business logic preserved from legacy system recording:
  // Requirement: Claim ID must follow the 'CLM-XXXX' pattern captured in session #842
  const handleUpdate = async () => {
    if (!validateClaimId(formData.id)) {
      setErrors(['Invalid Claim ID format detected in legacy validation logic.']);
      return;
    }
    
    const response = await submitClaimUpdate(formData);
    if (response.status === 200) onSuccess(response.data);
  };

  return (
    <Grid container spacing={3}>
      <Grid item xs={12}>
        <TextField 
          label="Claim ID" 
          value={formData.id} 
          onChange={(e) => setFormData({...formData, id: e.target.value})}
        />
      </Grid>
      {/* Dynamic fields extracted from observed user interactions */}
      <Button onClick={handleUpdate} variant="contained" color="primary">
        Sync with Legacy Backend
      </Button>
    </Grid>
  );
};

This isn't just "AI-generated code." It is code generated against the constraints of your existing system. The API bridge is automatically scaffolded based on the network traffic recorded during the session.

⚠️ Warning: Do not attempt to modernize business logic and UI frameworks simultaneously without a recorded baseline. This is the primary cause of "logic drift" where the new system behaves differently than the old one in subtle, catastrophic ways.

The Replay Workflow: 4 Steps to Modernization#

We have replaced the 18-month "archaeology" phase with a streamlined four-step process.

Step 1: Record and Catalog#

Subject Matter Experts (SMEs) perform their daily tasks while Replay records the session. This isn't just a screen recording; it's a deep-packet capture of the application's state. We build a Library of every interaction, creating a visual Design System from your existing assets.

Step 2: Architecture Mapping (Flows)#

Replay’s Flows feature automatically maps the dependencies. It identifies which legacy APIs are called, which database views are touched, and how data flows between screens. This turns the "black box" into a transparent architectural diagram.

Step 3: Blueprint Generation#

Using the Blueprints editor, architects review the extracted components and logic. Here, you can decide which parts of the legacy logic to keep and which to refactor. The AI Automation Suite suggests modern patterns to replace deprecated legacy calls.

Step 4: Automated Testing & Audit#

Before deployment, Replay generates a Technical Debt Audit. It highlights logic that was never triggered during recordings (dead code) and generates E2E tests in Playwright or Cypress that compare the modern component's output against the legacy recording.

💡 Pro Tip: Use the "Technical Debt Audit" to justify the removal of features. If a feature wasn't used in 100 hours of SME recordings, it likely doesn't need to be migrated.

Solving the Documentation Gap in Regulated Industries#

For Financial Services and Healthcare, "we don't know how it works" isn't just a technical problem—it's a compliance risk. Manual documentation is prone to omission, which leads to security vulnerabilities.

Replay is built for these high-stakes environments. With SOC2 compliance, HIPAA-readiness, and On-Premise deployment options, you can record sensitive workflows without data leaving your perimeter.

API Contract Generation#

One of the most painful parts of modernization is the API. Legacy systems often have undocumented, monolithic endpoints that return massive JSON (or XML) blobs. Replay observes these payloads and generates TypeScript interfaces and OpenAPI (Swagger) specifications automatically.

typescript
// Generated API Contract from Replay Network Capture
// Endpoint: /api/v1/underwriting/calculate-risk
// Observed in 14 distinct workflows

export interface UnderwritingResponse {
  riskScore: number; // Range 0-100
  factors: string[];
  lastUpdated: string; // ISO 8601
  // Note: Field 'legacy_flag_7' was observed but never utilized by the UI
  // Recommendation: Deprecate in modern implementation
  legacy_flag_7?: boolean; 
}

Why Understanding beats Rewriting#

The mantra of "The future isn't rewriting from scratch—it's understanding what you already have" is our guiding principle. When you rewrite from scratch, you lose the "tribal knowledge" embedded in the code. When you use Replay to reverse engineer the system, you preserve that knowledge while upgrading the delivery mechanism.

• •70% average time savings compared to traditional manual discovery.
• •From 18-24 months to days/weeks for initial component extraction.
• •Document without archaeology: No more digging through 20-year-old SVN repositories.

📝 Note: Replay doesn't just give you code; it gives you the context of why that code exists by linking every component back to the original video recording.

Frequently Asked Questions#

How long does legacy extraction take?#

While a manual audit takes 40 hours per screen, Replay reduces this to approximately 4 hours. Most enterprise clients see a fully documented and scaffolded modern frontend for a complex module in 2 to 8 weeks, depending on the number of unique workflows.

What about business logic preservation?#

Replay captures the effects of business logic. If a field becomes disabled when a certain checkbox is clicked, Replay identifies that state transition. While complex server-side COBOL logic remains on the server, Replay perfectly documents the interface and expected behavior, allowing you to wrap it in a modern API or rewrite the logic with a clear set of requirements.

Does this work with any legacy stack?#

Yes. Because Replay operates on the visual and network layers, it is agnostic to the backend. Whether your system is Mainframe-backed, PowerBuilder, Delphi, or an early 2000s Java monolith, if it has a web-accessible UI or can be rendered in a browser/terminal emulator, Replay can extract it.

How does this handle security and PII?#

Replay includes automated PII masking. During the recording phase, sensitive data can be redacted at the source so that it never enters the Replay Library. Our On-Premise version ensures that all extraction and AI processing happen within your own VPC.

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