Stop Interviewing Users: Why Recording Real Workflows Beats Subject Matter Expert Interviews

The most expensive part of your legacy modernization project isn't the coding—it's the lying. Your Subject Matter Experts (SMEs) are lying to you. They aren't doing it maliciously; they are doing it because human memory is lossy, documentation is nonexistent, and "how the system works" has diverged from "how the system is used" over a decade of patches and workarounds.

When you interview a user to document a legacy workflow, you aren't getting a technical specification. You are getting a filtered, idealized version of a process that ignores the 40% of edge cases that actually keep the business running. This is why 70% of legacy rewrites fail or exceed their timelines. We continue to treat software archaeology as a social exercise when it should be a data science exercise.

TL;DR: Stop relying on unreliable human interviews for system requirements; use Visual Reverse Engineering to record real workflows and generate 100% accurate React components and API contracts automatically.

The SME Paradox: Why Interviews Kill Modernization Projects#

In the enterprise, we’ve been conditioned to believe that the "Discovery Phase" requires months of workshops, sticky notes, and recorded Zoom interviews. This approach is fundamentally flawed. 67% of legacy systems lack any form of up-to-date documentation. When you ask a claims adjuster in an insurance firm or a floor manager in a manufacturing plant how they use a 20-year-old COBOL or Java Swing interface, they describe the "Happy Path."

They forget the three "ghost clicks" they have to perform to refresh the buffer. They forget the specific sequence of keys required to bypass a validation error that was never fixed in 2008. They forget the data transformation that happens in their head before they hit "Submit."

If you build your new system based on these interviews, you will ship a product that is technically "modern" but functionally broken for the business. You aren't modernizing; you're guessing.

The True Cost of Manual Archaeology#

Manual reverse engineering is a massive drain on high-value engineering talent. Currently, the industry average for manually documenting and recreating a single legacy screen—including its state management, validation logic, and API calls—is approximately 40 hours.

With Replay, that timeline drops to 4 hours.

Moving from "Black Box" to Documented Codebase#

The global technical debt bubble has reached $3.6 trillion. Most of this debt is locked inside "black box" systems where the original developers have long since retired, and the source code—if it exists—is a spaghetti mess of undocumented side effects.

Instead of trying to read the code, we should be watching the execution. By recording real user workflows, Replay captures the actual state transitions and data shapes of the legacy system. It doesn't matter if the backend is a mainframe or a monolithic .NET app; if it renders to a screen, it can be reverse-engineered.

Extracting Logic, Not Just Layout#

Modernization isn't just about making things look "Web 2.0." It's about preserving business logic while shedding technical debt. When Replay records a workflow, it isn't just taking a video; it is capturing the DOM mutations, the network requests, and the internal state.

Here is an example of the type of clean, functional React code Replay generates from a recorded legacy workflow. Notice how it preserves the business-critical data mapping while using modern hooks and TypeScript.

typescript
// Generated by Replay Visual Reverse Engineering
// Source: Legacy Claims Portal - Settlement Workflow
import React, { useState, useEffect } from 'react';
import { Button, TextField, Alert } from '@/components/ui';
import { useLegacyBridge } from '@/hooks/useLegacyBridge';

interface SettlementData {
  claimId: string;
  policyType: 'AUTO' | 'HOME' | 'LIFE';
  adjustmentAmount: number;
  isExpedited: boolean;
}

export const SettlementForm: React.FC<{ id: string }> = ({ id }) => {
  const [data, setData] = useState<SettlementData | null>(null);
  const [error, setError] = useState<string | null>(null);
  const { fetchLegacyState, submitToModernAPI } = useLegacyBridge();

  // Replay captured this specific sequence: 
  // 1. Fetch from legacy SOAP endpoint
  // 2. Transform to modern JSON schema
  useEffect(() => {
    async function init() {
      const legacyRaw = await fetchLegacyState(id);
      setData({
        claimId: legacyRaw.CID_VAL,
        policyType: legacyRaw.P_TYPE === 1 ? 'AUTO' : 'HOME',
        adjustmentAmount: parseFloat(legacyRaw.ADJ_AMT),
        isExpedited: legacyRaw.EXP_FLG === 'Y'
      });
    }
    init();
  }, [id]);

  const handleApprove = async () => {
    if (!data) return;
    try {
      // Logic preserved from recorded E2E flow
      await submitToModernAPI('/v1/settlements/approve', data);
    } catch (err) {
      setError("Settlement exceeds threshold for automated approval.");
    }
  };

  if (!data) return <div>Loading legacy context...</div>;

  return (
    <div className="p-6 space-y-4 border rounded-lg shadow-sm">
      <h2 className="text-xl font-bold">Claim Settlement: {data.claimId}</h2>
      {error && <Alert variant="destructive">{error}</Alert>}
      
      <TextField 
        label="Adjustment Amount" 
        value={data.adjustmentAmount} 
        readOnly 
      />
      
      <div className="flex gap-4">
        <Button onClick={handleApprove} variant="primary">
          Approve Settlement
        </Button>
      </div>
    </div>
  );
};

💡 Pro Tip: Don't try to fix the business logic during the extraction phase. First, achieve functional parity using Replay's generated components. Once you have a documented, running React application, use your modern CI/CD pipeline to refactor.

The 3-Step Workflow: From Recording to React#

The transition from an 18-month "Big Bang" rewrite to a 4-week incremental modernization requires a shift in methodology. Here is how Enterprise Architects are using Replay to bypass the interview phase entirely.

Step 1: Record the Source of Truth#

Instead of a discovery meeting, give the user the Replay recorder. They perform their daily tasks—processing an invoice, onboarding a patient, or checking a credit limit. Replay captures the "Shadow IT" and the undocumented workarounds that SMEs never mention in interviews.

Step 2: Extract the Blueprint#

Replay’s AI Automation Suite analyzes the recording. It identifies recurring UI patterns (buttons, inputs, tables) and maps them to your organization’s Design System. It also extracts the API contract—the exact JSON or XML payload that the legacy system expects.

Step 3: Generate and Audit#

The platform generates a clean React codebase. This isn't "low-code" junk; it’s standard TypeScript that your developers can own. Replay also provides a Technical Debt Audit, flagging where the legacy system had redundant calls or security vulnerabilities (like PII in URLs) so you can fix them in the modern version.

💰 ROI Insight: A major financial services firm reduced their modernization timeline for a core banking module from 12 months to 6 weeks by using Replay to extract 150+ legacy screens, saving an estimated $1.2M in engineering hours.

Preserving API Contracts Without Documentation#

One of the biggest risks in legacy modernization is breaking the "contract" between the frontend and the backend. In most 15-year-old systems, the API documentation is either a PDF from 2011 or simply non-existent.

Replay acts as a transparent proxy during the recording phase, generating OpenAPI (Swagger) specifications based on actual traffic. This allows you to build modern backends that are guaranteed to support the frontend's requirements.

yaml
# Generated OpenAPI Spec from Replay Workflow Recording
openapi: 3.0.0
info:
  title: Legacy Insurance API (Extracted)
  version: 1.0.0
paths:
  /api/v2/underwriting/calculate:
    post:
      summary: Extracted from "Standard Risk Assessment" Workflow
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                applicant_age: { type: integer }
                smoke_history: { type: boolean }
                coverage_limit: { type: number }
                # Replay identified this hidden field required by the legacy backend
                _internal_audit_token: { type: string }
      responses:
        '200':
          description: Success

⚠️ Warning: Never assume a legacy field is deprecated just because it isn't in the UI. Replay often finds "hidden" fields that are required for backend database triggers. Removing these during a manual rewrite is a leading cause of production outages.

Built for the Regulated Enterprise#

We understand that you can't just "upload your legacy system to the cloud." For industries like Healthcare, Government, and Telecom, data privacy is non-negotiable.

• •SOC2 & HIPAA Ready: Replay is designed to handle sensitive data with PII masking during the recording phase.
• •On-Premise Availability: Run the entire extraction suite within your own VPC or air-gapped environment.
• •Audit Trails: Every component generated by Replay is linked back to the original video recording, providing a 1:1 audit trail of why a specific piece of logic was implemented.

Frequently Asked Questions#

How long does legacy extraction take?#

While a manual rewrite of a complex enterprise module takes 18-24 months, Replay typically reduces this to days or weeks. A single complex screen can be recorded, analyzed, and converted into a documented React component in under 4 hours.

What about business logic preservation?#

Replay captures the behavioral logic of the interface. If a field becomes disabled when a certain checkbox is clicked, Replay identifies that state dependency and replicates it in the generated code. It moves you from "guessing the logic" to "observing the logic."

Does this replace my developers?#

No. Replay replaces the "grunt work" of archaeology. It frees your Senior Architects and Engineers to focus on high-level system design, security, and performance, rather than spending weeks trying to figure out how a legacy JSP page handles form validation.

Can Replay handle mainframes or terminal emulators?#

Yes. As long as the workflow can be accessed via a browser or a desktop client, Replay's visual engine can map the interactions. We specialize in "the last mile" of legacy systems that are blocking digital transformation.

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