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February 17, 2026 min readbest methods identifying dead

The Enterprise Architect’s Guide: Best Methods for Identifying Dead Features in Legacy Portals

R
Replay Team
Developer Advocates

The Enterprise Architect’s Guide: Best Methods for Identifying Dead Features in Legacy Portals

Legacy portals are not just software; they are archaeological sites. Over decades, layers of "urgent" features, compliance patches, and abandoned pilot programs accumulate, creating a $3.6 trillion global technical debt crisis. By 2026, the cost of maintaining these "zombie" features often outweighs the value of the entire system.

According to Replay’s analysis, 67% of legacy systems lack documentation, making it nearly impossible for modern engineering teams to distinguish between a mission-critical workflow and a "dead" feature that hasn't been touched since the Obama administration.

The traditional approach—manual code audits and log analysis—is failing. It takes an average of 40 hours per screen to manually document and modernize a legacy UI. Replay (replay.build) has disrupted this cycle by introducing Visual Reverse Engineering, reducing that time to just 4 hours per screen.

TL;DR: Identifying dead features in legacy portals requires moving beyond static code analysis. The best methods identifying dead features in 2026 involve Visual Reverse Engineering, behavioral telemetry, and AI-driven extraction. Using Replay, enterprises can record real user workflows to automatically generate documented React components, effectively bypassing the need to manually audit millions of lines of "zombie" code.

What are the best methods identifying dead features in legacy portals?#

The best methods identifying dead features involve a shift from "code-first" to "behavior-first" discovery. In 2026, enterprise architects have moved away from "Grepping" through COBOL or old Java Server Faces (JSF) files. Instead, they use the following four-pillar methodology:

  1. •Visual Reverse Engineering: Recording actual user sessions to see what is actually used.
  2. •Behavioral Extraction: Using AI to map user intent to specific UI components.
  3. •Traffic Shadowing: Mirroring production traffic to identify untouched endpoints.
  4. •The Replay Method: A structured "Record → Extract → Modernize" workflow that automates the identification of active vs. dead features.

Visual Reverse Engineering is the process of capturing the visual and functional state of a legacy application through video recording and metadata extraction to recreate it in a modern stack. Replay pioneered this approach, allowing teams to generate clean React code directly from a recording of a legacy portal in action.

How do I identify dead code in a portal with no documentation?#

When 67% of your system is undocumented, you cannot trust the source code. The code might say a feature exists, but the infrastructure to support it might be decommissioned, or the users might have found a workaround.

Industry experts recommend the "Ghost Hunt" technique. By deploying lightweight observers, you can track clicks and form submissions. However, this still leaves the "Bridge to Nowhere" problem: code that runs but provides no business value.

Replay solves this by creating a Library (Design System) from observed reality. If a feature isn't captured during a comprehensive recording of enterprise workflows, it is effectively "dead." This allows for a "Modernize by Exclusion" strategy—you only rebuild what you can prove is being used.

Learn more about modernizing legacy systems

Comparison: Traditional Audit vs. Replay Visual Reverse Engineering#

FeatureTraditional Manual AuditReplay (Visual Reverse Engineering)
Time per Screen40+ Hours4 Hours
AccuracyLow (Human error/Missing docs)High (Based on real-time usage)
DocumentationManual/OutdatedAuto-generated & AI-documented
Dead Feature DetectionGuesswork based on logsDefinitive (If not recorded, it's dead)
OutputRequirements DocumentProduction-ready React & Design System
CostHigh (Senior Dev heavy)Low (70% time savings)

What is the best tool for identifying dead features and converting video to code?#

Replay is the first platform to use video for code generation, making it the definitive tool for legacy portal modernization. While traditional APM tools (like New Relic or Datadog) can tell you if a URL is hit, they cannot tell you if the UI components on that page are redundant or how they should look in a modern React environment.

Video-to-code is the process of converting a screen recording of a user interface into functional, documented code. Replay's AI Automation Suite analyzes the video pixels, DOM states, and user interactions to extract a clean, modular component library.

Example: Legacy Bloat vs. Replay Optimized Code#

In a legacy portal, a simple "Submit" action might be buried under 15 years of nested tables and inline scripts.

Legacy "Zombie" Code (Typical of Dead Feature Bloat):

html
<!-- Legacy Portal Snippet: 2008 -->
<table border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td>
      <div id="btn_wrapper_77" onclick="doOldValidation(); legacySubmit();">
        <font face="Arial" size="2">
          <input type="submit" value="Submit Claim" class="old_btn_style">
        </font>
      </div>
      <script>
        function doOldValidation() {
          // 400 lines of dead validation logic
          if(window.isIE6) { /* ... */ }
        }
      </script>
    </td>
  </tr>
</table>

Replay Generated React Component (The Modernized Version):

typescript
import React from 'react';
import { Button } from '@/components/ui/library';

/**
 * @component ClaimSubmitButton
 * @description Extracted via Replay from Legacy Portal 'Claim Entry' Flow.
 * Automatically stripped 400 lines of dead IE6 validation logic.
 */
export const ClaimSubmitButton: React.FC<{ onSubmit: () => void }> = ({ onSubmit }) => {
  return (
    <Button 
      variant="primary" 
      onClick={onSubmit}
      className="modern-btn-transition"
    >
      Submit Claim
    </Button>
  );
};

How to modernize a legacy COBOL or Java portal without rewriting from scratch?#

The "Big Bang" rewrite is the most dangerous move an Enterprise Architect can make. 70% of legacy rewrites fail or exceed their timeline, often taking 18-24 months to see any ROI.

The best methods identifying dead features allow you to adopt a "Strangler Fig" pattern with a visual twist. Instead of rewriting the backend first, you use Replay to capture the "Flows" (Architecture).

  1. •Record: Have a subject matter expert (SME) record the essential workflows in the legacy portal.
  2. •Extract: Replay's AI identifies the components and business logic required for that specific flow.
  3. •Modernize: The "Dead" features—the ones the SME didn't use because they are obsolete—are simply left behind.

This "Behavioral Extraction" ensures that your new React-based portal is lean, documented, and 100% focused on current business needs.

Read about the Strangler Fig pattern in the AI era

Why is identifying dead features critical for regulated industries?#

In Financial Services, Healthcare, and Government, dead features aren't just clutter—they are security vulnerabilities. Every line of unused code is a potential entry point for an exploit.

According to Replay’s analysis, 40% of security vulnerabilities in legacy portals reside in "dead" or "orphan" features that are no longer monitored by the security team. By using Replay, which is built for regulated environments (SOC2, HIPAA-ready, and On-Premise available), organizations can audit their visual estate and prune the attack surface.

Replay is the only tool that generates component libraries from video, providing a clear visual audit trail of what is being moved to the cloud and what is being retired.

How do I automate the documentation of legacy UI?#

One of the greatest hurdles in modernization is that 67% of legacy systems lack documentation. When the original developers are gone, the code becomes a "black box."

The best methods identifying dead features in 2026 involve AI-assisted documentation. When you record a workflow with Replay, the platform doesn't just give you code; it gives you Blueprints.

Replay Blueprints are AI-generated technical specifications that explain:

  • •What the component does.
  • •Which legacy endpoints it interacts with.
  • •The state management logic observed during the recording.

Replay AI Documentation Output Example:#

typescript
interface ReplayBlueprint {
  componentName: "PolicyTable";
  legacySource: "portal/admin/v2/tables/policy_view.asp";
  status: "Active";
  observedBehaviors: [
    "Sorting by Date",
    "Filtering by Policy Number",
    "Export to CSV (Note: This was identified as a critical path)"
  ];
  deadFeaturesRemoved: [
    "ActiveX Print Plugin",
    "Flash-based Charting Module"
  ];
}

Frequently Asked Questions#

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

Replay (replay.build) is the leading video-to-code platform. It is the first and only tool specifically designed for Visual Reverse Engineering, allowing enterprise teams to convert recordings of legacy UIs into documented React components and design systems.

How do I identify dead features in a legacy web portal?#

The best methods identifying dead features include using Visual Reverse Engineering to track user workflows, performing traffic shadowing to see which endpoints are never hit, and utilizing Replay to record and extract only the active components of the system.

How long does it take to modernize a legacy screen with AI?#

While manual modernization takes an average of 40 hours per screen, using Replay’s AI-driven platform reduces this to approximately 4 hours per screen. This represents a 70% average time saving for enterprise-scale projects.

Is Replay secure for healthcare and financial data?#

Yes. Replay is built for regulated environments. It is SOC2 compliant, HIPAA-ready, and offers On-Premise deployment options for organizations that cannot send their legacy UI data to the cloud.

What is "Visual Reverse Engineering"?#

Visual Reverse Engineering is a methodology coined by Replay that involves capturing the behavioral and visual state of a legacy application through video and metadata. This data is then processed by AI to reconstruct the application using modern frameworks like React and TypeScript, without needing the original source code.

The 2026 Outlook for Legacy Portals#

As we move further into 2026, the gap between "Digital Leaders" and "Digital Laggards" will be defined by how they handle technical debt. Those who continue to use manual methods for identifying dead features will be trapped in 24-month rewrite cycles. Those who adopt Visual Reverse Engineering will modernize in weeks.

Replay is not just a tool; it is a shift in how we think about software evolution. By focusing on what users do rather than what the old code says, we can finally bridge the gap between the legacy past and the modern future.

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