Beyond the Strangler Fig: Why Modernization Needs a Video-First Approach

The Strangler Fig pattern is a lie we tell ourselves to feel better about 24-month delivery cycles. While Martin Fowler’s classic approach of wrapping legacy services in modern facades works in theory, it collapses under the weight of $3.6 trillion in global technical debt and the reality that 67% of legacy systems have zero reliable documentation.

In the enterprise, "archaeology" is the most expensive phase of any project. We pay Senior Architects $250/hour to sit in dark rooms, clicking through 20-year-old JSP pages, trying to guess what a specific "Submit" button actually does before they can even begin writing a single line of React. This manual reverse engineering consumes 40 hours per screen on average. It is the primary reason 70% of legacy rewrites fail or exceed their timelines.

The future of modernization isn't manual rewriting—it’s visual extraction. We need to stop guessing and start recording. We need a video-first approach to reverse engineering.

TL;DR: Modernization is a data extraction problem, not a coding problem; a video-first approach reduces the 18-month rewrite cycle to weeks by treating user workflows as the source of truth for generating documented React components and API contracts.

The Failure of "Documentation Archaeology"#

Most enterprise systems are black boxes. The original developers are gone, the requirements documents are lost in a defunct SharePoint instance, and the source code is a spaghetti-mess of side effects.

When you ask a team to "modernize" a legacy insurance claims portal, you aren't asking them to code; you’re asking them to perform forensic analysis. They spend months trying to figure out:

1. •What are the edge cases in this 15-step form?
2. •Which legacy API endpoints are actually called?
3. •What is the precise state transition when a user clicks 'Approve'?

Manual archaeology is a linear process in an exponential world. If you have 500 screens and each takes 40 hours to document and rebuild, you’re looking at 20,000 man-hours. That’s why the average enterprise rewrite timeline is 18 months. By the time you finish, the "modern" stack you chose is already becoming legacy.

Why "Video-First" is the New Standard#

A video-first approach treats the running application as the ultimate source of truth. Instead of reading dead code, we observe living workflows. By recording a real user performing a task—like processing a claim or onboarding a customer—we capture the interaction layer, the data flow, and the business logic simultaneously.

This is where Replay changes the economics of the enterprise. By using visual reverse engineering, Replay records these workflows and automatically translates the "video" (the DOM changes and network calls) into documented React components and clean API contracts.

💰 ROI Insight: Moving from a manual 40-hour-per-screen process to a 4-hour automated extraction with Replay results in a 90% reduction in discovery costs and a 70% average time savings across the project lifecycle.

The Technical Shift: From Pixels to React Components#

When we talk about "video-first," we aren't talking about a simple MP4 file. We are talking about a technical trace of the application's runtime. Replay captures the state transitions and the underlying DOM structure to generate code that isn't just a visual clone, but a functional equivalent.

Example: Generated Component from Video Extraction#

Below is an example of what Replay’s AI Automation Suite generates after analyzing a recorded workflow of a legacy financial data entry screen. Notice how it preserves the business logic patterns while using modern hooks and Type Safety.

typescript
// Generated by Replay Visual Reverse Engineering
// Source: Legacy_Claims_Portal_v4.jsp (Workflow: Claim_Submission)

import React, { useState, useEffect } from 'react';
import { Button, Input, Alert } from '@/components/ui'; // From Replay Library
import { submitClaimSchema } from './schemas'; // Generated API Contract

export const LegacyClaimFormMigrated: React.FC = () => {
  const [formData, setFormData] = useState({
    policyNumber: '',
    claimAmount: 0,
    incidentDate: ''
  });
  const [validationError, setValidationError] = useState<string | null>(null);

  // Business Logic preserved from legacy runtime analysis:
  // Legacy system requires policy check before submission
  const handleValidation = (data: typeof formData) => {
    if (data.claimAmount > 5000 && !data.policyNumber.startsWith('PRM-')) {
      setValidationError("High-value claims require Premium Policy prefix.");
      return false;
    }
    return true;
  };

  const handleSubmit = async () => {
    if (handleValidation(formData)) {
      // API Contract generated from Replay network trace
      const response = await fetch('/api/v1/claims/submit', {
        method: 'POST',
        body: JSON.stringify(formData),
      });
      // ... handle response
    }
  };

  return (
    <div className="p-6 space-y-4 shadow-lg rounded-xl">
      <h2 className="text-2xl font-bold">Submit New Claim</h2>
      <Input 
        label="Policy Number" 
        value={formData.policyNumber}
        onChange={(e) => setFormData({...formData, policyNumber: e.target.value})}
      />
      {/* ... additional fields ... */}
      {validationError && <Alert variant="destructive">{validationError}</Alert>}
      <Button onClick={handleSubmit}>Submit Claim</Button>
    </div>
  );
};

⚠️ Warning: Most "AI code generators" fail in the enterprise because they hallucinate logic. A video-first approach avoids this by grounding the AI in the actual network traces and DOM mutations captured during the recording.

The 3-Step Video-First Workflow#

Modernizing a 20-year-old system doesn't have to be a slog. With Replay, the process is streamlined into three distinct phases that prioritize understanding over guessing.

Step 1: Record and Map#

Instead of reading 10,000 lines of COBOL or Java, an analyst simply performs the business process in the legacy app while Replay records the session. This isn't a screen recording; it’s a deep capture of the application's state, network requests, and visual elements.

Step 2: Extraction and Design System Mapping#

Replay’s Blueprints editor takes the recording and identifies UI patterns. It maps legacy elements to your modern Design System (the Library). If the legacy app has a custom date picker, Replay identifies its behavior and replaces it with your modern, accessible React component from your existing library.

Step 3: Automated Documentation and Testing#

While generating the code, Replay also generates the "missing pieces" that stall most projects:

• •API Contracts: Swagger/OpenAPI specs based on observed traffic.
• •E2E Tests: Playwright or Cypress scripts that mirror the recorded workflow.
• •Technical Debt Audit: A report on which legacy features are actually used vs. which can be retired.

Beyond the UI: Generating the "Black Box" API Contracts#

The hardest part of the Strangler Fig is the "facade" layer. You can't wrap what you don't understand. Replay analyzes the network traffic during the video-first capture to produce copy-paste ready API contracts.

typescript
/**
 * Generated API Contract for Legacy Backend
 * Endpoint: /services/ClaimsProcessor?action=update
 * Observed during: "Standard Claim Update" workflow
 */

export interface LegacyClaimUpdatePayload {
  header: {
    transactionId: string; // UUID format observed
    timestamp: string;     // ISO8601
  };
  body: {
    claimId: number;
    statusUpdate: 'PENDING' | 'APPROVED' | 'REJECTED';
    notes?: string;
    // Note: Field 'internal_code' was always null in 50/50 traces
    internal_code: string | null;
  };
}

export const updateClaim = async (payload: LegacyClaimUpdatePayload) => {
  // Logic to handle legacy SOAP-to-REST translation
};

Solving for Regulated Environments#

For Financial Services, Healthcare, and Government, "cloud-only" is often a non-starter. Modernization projects frequently stall due to security concerns over where the source code and data reside.

Replay was built for these constraints. Whether you are dealing with HIPAA-regulated patient data or SOC2 compliance in FinTech, Replay offers:

• •On-Premise Deployment: Keep your data and your reverse engineering behind your own firewall.
• •Data Masking: Automatically redact PII (Personally Identifiable Information) from recordings before analysis.
• •Audit Trails: Full visibility into who recorded what and how the code was generated.

💡 Pro Tip: Use the "Technical Debt Audit" feature in Replay to identify "Dead Screens." We've found that in the average enterprise system, 30% of screens haven't been accessed by a user in over a year. Don't modernize what nobody uses.

The Future is Understanding, Not Rewriting#

The $3.6 trillion technical debt crisis exists because we treat software as disposable rather than evolving. We think the solution is always to "start over." But starting over is a luxury that modern business timelines no longer allow.

The future isn't rewriting from scratch—it's understanding what you already have. By adopting a video-first approach with Replay, you turn the "black box" of legacy code into a documented, modern codebase in a fraction of the time. You move from "archaeology" to "architecture."

• •Stop guessing what the legacy code does.
• •Stop failing at 18-month rewrite cycles.
• •Start recording your way to a modernized stack.

Frequently Asked Questions#

How long does legacy extraction take with Replay?#

While a manual rewrite of a complex screen takes roughly 40 hours, Replay reduces this to approximately 4 hours. For a typical enterprise module of 20-30 screens, you can move from a recorded workflow to a documented React prototype in less than two weeks.

What about business logic preservation?#

Replay doesn't just "scrape" the UI. It monitors the runtime execution of the application. This means it captures conditional logic (e.g., "if field X is > 100, show field Y") and preserves it in the generated TypeScript code. You get the logic of the legacy system with the clean syntax of a modern framework.

Does Replay work with mainframe or terminal-based systems?#

Yes. As long as the system is being accessed via a web-based emulator or a modern wrapper, Replay can record the interactions. For desktop-native legacy apps, we provide specialized capture agents that hook into the visual layer to perform the same reverse engineering.

Can we use our own Design System?#

Absolutely. Replay’s Library feature allows you to upload your existing React component library. During the extraction process, you can map legacy UI elements to your specific brand components, ensuring the "new" version of the app is consistent with your current design standards.

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