Legacy Feature Bloat: Using Workflow Recording to Identify and Prune Unused UI

The average enterprise application contains 40% more code than it needs to function, yet we treat every line like a sacred artifact. This "sacred artifact" syndrome is the primary driver behind the $3.6 trillion global technical debt crisis. When you are tasked with modernizing a 15-year-old insurance portal or a legacy banking terminal, you aren't just fighting outdated syntax; you are fighting decades of Legacy Feature Bloat.

TL;DR: Visual Reverse Engineering via workflow recording allows architects to identify and extract only the active business logic, reducing modernization scope by up to 60% and cutting timelines from years to weeks.

The Hidden Tax of Legacy Feature Bloat#

In my two decades as an Enterprise Architect, I’ve seen the same pattern repeat: a "Big Bang" rewrite is greenlit with an 18-month timeline. Twelve months in, the team is still performing "code archaeology," trying to figure out if the

module is actually being used by anyone in the Omaha branch.

The result? 70% of these legacy rewrites fail or significantly exceed their timelines. We fail because we try to rewrite the codebase instead of the business value.

Legacy systems are black boxes. Documentation is non-existent in 67% of cases. When you can't see what's inside, you default to "lift and shift," migrating bugs, security vulnerabilities, and thousands of lines of dead UI code into your shiny new React architecture. This isn't modernization; it's just moving the mess to a more expensive neighborhood.

Why Manual Audits Fail: The Archaeology Problem#

The traditional approach to pruning Legacy Feature Bloat is a manual audit. An architect sits with a developer, looks at a screen, and tries to trace the execution path through a labyrinth of JSP, COBOL, or Silverlight.

It takes an average of 40 hours per screen to manually document, audit, and prepare a legacy component for migration. In a system with 500+ screens, you’ve already spent $1M before writing a single line of modern code.

Modernization Strategy Comparison#

⚠️ Warning: Attempting to modernize without first identifying unused UI components leads to "Parity Traps," where teams spend months recreating features that no user has touched since 2014.

Visual Reverse Engineering: Turning User Workflows into Truth#

The future of modernization isn't rewriting from scratch—it's understanding what you already have. This is where Replay changes the economics of technical debt.

Instead of reading dead code, Replay uses workflow recording as the source of truth. By recording a real user performing a task—say, processing a claim or onboarding a patient—Replay captures the exact execution path, the data structures, and the UI components required for that specific business outcome.

Everything else? That's the bloat. You don't need to document it, you don't need to migrate it, and you certainly don't need to pay for it.

The Replay AI Automation Suite#

Replay doesn't just record video; it deconstructs the application layer by layer:

• •Library (Design System): Automatically extracts UI elements into a modern React component library.
• •Flows (Architecture): Maps the sequence of events and state changes.
• •Blueprints (Editor): Provides a workspace to refine the extracted code before deployment.

Step-by-Step: Pruning the Bloat with Replay#

To effectively prune Legacy Feature Bloat, we shift from a code-first mindset to a workflow-first mindset.

Step 1: Workflow Mapping#

Identify the core 20% of workflows that drive 80% of the business value. Using Replay, record these workflows in the production or staging environment. This creates a functional map of what "done" looks like.

Step 2: Automated Extraction#

Replay analyzes the recording and identifies the active components. It ignores the "Zombie UI"—buttons that lead to dead links, tabs that no longer load data, and legacy export functions that were replaced by a different system years ago.

Step 3: Component Generation#

Replay generates documented React components based on the recorded behavior. This isn't a "transpilation" of old code; it's a clean-room implementation based on observed logic.

typescript
// Example: Replay-generated component from a legacy workflow recording
// This component captures the actual business logic observed, 
// stripping away 1,500 lines of unused legacy state management.

import React, { useState, useEffect } from 'react';
import { ModernButton, ModernInput, Card } from '@enterprise-ds/core';

interface ClaimData {
  claimId: string;
  amount: number;
  status: 'PENDING' | 'APPROVED' | 'REJECTED';
}

export const ClaimApprovalWorkflow: React.FC<{ id: string }> = ({ id }) => {
  const [data, setData] = useState<ClaimData | null>(null);

  // Logic extracted from legacy XHR/SOAP intercepts during recording
  const handleApprove = async () => {
    const response = await fetch(`/api/v2/claims/${id}/approve`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' }
    });
    if (response.ok) {
      // Logic preserved from legacy "Success" state
      window.dispatchEvent(new CustomEvent('notify', { detail: 'Claim Processed' }));
    }
  };

  return (
    <Card title={`Processing Claim: ${id}`}>
      <div className="flex flex-col gap-4">
        <ModernInput label="Adjusted Amount" value={data?.amount} readOnly />
        <div className="flex gap-2">
          <ModernButton variant="primary" onClick={handleApprove}>
            Approve Claim
          </ModernButton>
        </div>
      </div>
    </Card>
  );
};

💰 ROI Insight: Manual extraction takes 40 hours per screen. Replay reduces this to 4 hours. For a 100-screen application, that's a saving of 3,600 engineering hours.

Preserving Business Logic Without the Archaeology#

One of the biggest fears in modernization is losing "tribal knowledge" embedded in the code—that specific

statement that handles a regulatory edge case in New Jersey.

When you use Replay, you aren't guessing what the logic is. Replay generates API Contracts and E2E Tests based on the actual data flowing through the legacy system during the recording. If the legacy system sends a specific payload to a mainframe when a certain checkbox is clicked, Replay documents that contract.

Technical Debt Audit#

Before you migrate, Replay provides a Technical Debt Audit. This report highlights:

• •Redundant UI components
• •Overlapping API endpoints
• •Security vulnerabilities in the legacy data flow
• •Opportunities for component consolidation in your new Design System

Step 4: Verification and Documentation#

Once the clean components are extracted, Replay generates the documentation that was missing for 15 years. This includes the "why" behind the code, tied directly to the video recording of the workflow.

typescript
/**
 * REPLAY GENERATED DOCUMENTATION
 * Source Workflow: "Quarterly Tax Reconciliation"
 * Recorded User: Senior Analyst (ID: 882)
 * 
 * Logic Note: The 'calculateTax' function uses a weighted average 
 * based on the legacy 'RegionCode' mapping. Replay identified 
 * that only codes 01-14 are currently active in production.
 */
export function calculateTax(amount: number, region: string) {
  // ... extracted logic
}

Built for Regulated Environments#

We understand that Financial Services, Healthcare, and Government agencies can't just send their data to a public cloud. Replay is built for these constraints:

• •SOC2 & HIPAA Ready: Data privacy is baked into the extraction process.
• •On-Premise Availability: Keep your legacy source code and recordings within your firewall.
• •PII Redaction: Automated masking of sensitive data during the workflow recording process.

The Cost of Inaction#

Every month you delay modernization, you pay the "Legacy Tax." This tax manifests as slower release cycles, higher infrastructure costs, and the constant risk of a "Black Swan" event where the one developer who understands the legacy system retires.

By using Replay to identify and prune Legacy Feature Bloat, you transform modernization from a high-risk gamble into a predictable, engineering-led process. You stop being a digital archaeologist and start being a digital architect.

💡 Pro Tip: Don't try to record everything at once. Start with your most complex, least-documented module. Use Replay to extract it in a week, and use that win to build momentum for the rest of the project.

Frequently Asked Questions#

How long does legacy extraction take with Replay?#

While manual documentation takes 40+ hours per screen, Replay users typically see a fully documented React component and API contract ready for review within 4 hours of the initial recording. A complex module that would take months to rewrite can be extracted and refined in days.

What about business logic preservation?#

Replay captures the "Black Box" behavior. It monitors the inputs, outputs, and state changes of the legacy system. By generating E2E tests based on these real-world recordings, we ensure that the modern component behaves exactly like the legacy one, preserving all critical business rules without needing to read the original source code.

Does Replay require access to our source code?#

No. Replay performs Visual Reverse Engineering. It works by observing the application's behavior at the browser or interface level. This makes it ideal for legacy systems where the original source code is lost, obfuscated, or written in languages your current team doesn't support.

Can Replay handle complex, multi-step workflows?#

Yes. Replay's "Flows" feature is designed specifically for complex enterprise processes that span multiple screens and API calls. It creates a visual map of the entire sequence, ensuring that state is managed correctly across the new architecture.

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