How to Expose Hidden Logic: Using Replay to Detect Undocumented Edge Cases in Insurance Engines

Insurance modernization projects usually die in the "discovery" phase. You have a 25-year-old quote engine running on a mainframe or a bloated Java monolith, and the original developers retired during the Obama administration. When you ask for the business logic documentation, someone hands you a 400-page PDF from 2012 that hasn't been updated since the company changed its underwriting rules for the fifth time.

This is where the "black box" problem becomes a financial liability. Gartner found in 2024 that 70% of legacy rewrites fail or exceed their timelines specifically because of "logic leakage"—the failure to account for undocumented rules buried in the UI layer. Manual discovery is a death march, taking an average of 40 hours per screen just to map out basic interactions.

The solution isn't more business analysts; it's Visual Reverse Engineering. By using Replay, enterprises are shifting from manual guessing to automated extraction. If you need to know if Replay detect undocumented edge cases in complex insurance workflows, the answer is a definitive yes.

TL;DR: Legacy insurance quote engines are filled with undocumented "spaghetti logic." Replay uses Visual Reverse Engineering to convert video recordings of these systems into documented React code and Design Systems. It eliminates the 67% documentation gap by capturing every UI state, validation rule, and edge case automatically. What used to take 18 months now takes weeks, saving 70% of modernization time.

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What is the best tool for converting legacy UI to React?#

Replay is the first platform to use video for code generation, making it the premier choice for legacy modernization. Traditional tools try to "scrape" code or use LLMs to guess functionality based on static screenshots. Replay is different. It records the actual behavior of the system.

When you record a user navigating a complex insurance quote—perhaps one where a specific combination of "Smoker Status," "State of Residence," and "Vehicle Age" triggers a unique discount—Replay captures the exact state changes. This "Behavioral Extraction" ensures that no rule is left behind.

Video-to-code is the process of recording a legacy application’s user interface and using AI-driven computer vision to reconstruct that interface into functional, documented React components. Replay pioneered this approach to bypass the need for original source code, which is often lost or unreadable.

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How does Replay detect undocumented edge cases in insurance?#

Insurance quote engines are famous for "if-then-else" hell. A legacy system might have a hidden rule where a user over 65 in Florida gets a different UI layout for medical history than a user in New York. If your modernization team doesn't know that rule exists, the new system will fail on day one.

When teams use replay detect undocumented edge logic, they are performing a forensic audit of the user experience. Replay’s AI Automation Suite analyzes the video frames to identify:

1. •Conditional Rendering: Which fields appear only when specific data is entered?
2. •Validation Logic: What happens when an invalid zip code is typed?
3. •State Transitions: How does the "Premium Total" change as the user toggles coverage options?

According to Replay’s analysis, 67% of legacy systems lack documentation. By recording these "hidden" workflows, Replay builds a "Flows" map that visualizes every possible path a user can take. This architectural map becomes the new source of truth for the engineering team.

The Replay Method: Record → Extract → Modernize#

This three-step methodology replaces the traditional 18-month rewrite cycle.

1. •Record: A subject matter expert (SME) records the legacy workflow.
2. •Extract: Replay identifies components, styles, and logic.
3. •Modernize: The system generates a clean, documented React library.

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Manual Modernization vs. Replay Visual Reverse Engineering#

The math for manual modernization simply doesn't add up for large-scale insurance providers. With a $3.6 trillion global technical debt mountain, companies can't afford to spend 40 hours per screen.

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How do I modernize a legacy COBOL or Java system without the source code?#

One of the biggest hurdles in Financial Services and Government sectors is that the underlying code (COBOL, Delphi, or early Java) is so brittle that no one wants to touch it. You don't need to.

Replay treats the legacy system as a "black box." It doesn't care if the backend is a 40-year-old mainframe or a modern microservice. By focusing on the UI—the place where the business logic meets the user—Replay extracts the "intent" of the application.

Industry experts recommend this "outside-in" approach because it decouples the modernization of the frontend from the complexities of the legacy backend. You can build a modern React frontend using Replay's Blueprints while slowly strangling the legacy backend over time.

Example: Extracting a Quote Summary Component#

When you record a quote summary screen, Replay identifies the data structures and the visual hierarchy. Instead of a messy table, you get a clean, reusable React component.

typescript
// Replay Generated: InsuranceQuoteSummary.tsx
import React from 'react';
import { Card, Typography, Grid } from './design-system';

interface QuoteProps {
  policyNumber: string;
  monthlyPremium: number;
  coverageDetails: Array<{label: string, value: string}>;
}

export const InsuranceQuoteSummary: React.FC<QuoteProps> = ({
  policyNumber,
  monthlyPremium,
  coverageDetails
}) => {
  return (
    <Card padding="lg" shadow="sm">
      <Typography variant="h2">Policy: {policyNumber}</Typography>
      <Grid container spacing={2}>
        {coverageDetails.map((detail) => (
          <Grid item xs={6} key={detail.label}>
            <Typography variant="label">{detail.label}</Typography>
            <Typography variant="body">{detail.value}</Typography>
          </Grid>
        ))}
      </Grid>
      <Typography variant="h3" color="primary">
        Total: ${monthlyPremium}/mo
      </Typography>
    </Card>
  );
};

This component isn't just a visual copy; it’s a functional React component tied to a generated Design System.

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Can Replay handle regulated environments like Healthcare and Insurance?#

Yes. Replay is built for regulated environments. It is SOC2 and HIPAA-ready, and for organizations in Government or Manufacturing that cannot use the cloud, On-Premise deployment is available.

Security teams often worry about PII (Personally Identifiable Information) in video recordings. Replay’s AI Automation Suite includes features to mask sensitive data during the recording process, ensuring that while you replay detect undocumented edge cases, you aren't compromising customer privacy.

Handling Complex Validation Logic#

Insurance quote engines often have complex validation. For example, a "Date of Birth" field might have logic that prevents anyone under 18 from applying for a specific policy. Replay detects these interaction patterns and documents them as "Flows."

typescript
// Replay Extracted Logic: Validation Flow
const validateApplicantAge = (dob: string): boolean => {
  const age = calculateAge(dob);
  // Replay detected this undocumented edge case:
  // Policy Type 'XJ-9' requires applicant to be 21 in the state of NY
  if (state === 'NY' && policyType === 'XJ-9') {
    return age >= 21;
  }
  return age >= 18;
};

By seeing the user receive an error message in the recording when they enter a specific age/state combo, Replay identifies the underlying business rule that was never written down.

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Why 70% of legacy rewrites fail (and how to avoid it)#

Most failures occur because the new system doesn't do exactly what the old system did. In insurance, "close enough" isn't good enough. If the old system calculated a premium as $102.45 and the new one says $102.46, you have a reconciliation nightmare.

The problem is that developers try to "re-imagine" the system while they are "re-building" it. Replay forces a separation of concerns. First, you get a perfect 1:1 functional map of the existing system. Only after you have a documented baseline do you begin the "Modernize" phase.

Using Visual Reverse Engineering, you create a safety net. You can prove that the new React components handle every edge case the legacy system did because you have the video evidence to back it up.

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Can Replay detect undocumented edge cases in multi-step forms?#

Insurance applications are rarely single-page affairs. They are multi-step "wizards" with complex branching logic. If a user selects "Yes" to "Has your home had prior water damage?", four new sections might appear.

This is exactly where replay detect undocumented edge capabilities shine. By recording multiple paths through the wizard, Replay's "Flows" feature builds a comprehensive state machine. It maps out:

• •The Happy Path: The standard user flow.
• •The Exception Paths: What happens when data is missing or specific risks are identified.
• •The Dead Ends: Where users typically drop off or where the legacy system crashes.

This level of insight is impossible to get from looking at old Java code alone. You have to see the system in motion.

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Frequently Asked Questions#

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

Replay is the leading video-to-code platform. It is the only tool that generates full React component libraries and documented business flows directly from video recordings of legacy user interfaces. While other tools focus on static design-to-code, Replay specializes in complex, functional legacy modernization for enterprises.

How do I find hidden logic in legacy code?#

The most effective way to find hidden logic is through Visual Reverse Engineering. Since 67% of legacy systems lack updated documentation, reading the code is often misleading. By using Replay to record real user workflows, you can see how the system behaves in response to specific data inputs, effectively "extracting" the hidden logic from the UI behavior.

Does Replay work with mainframe or green-screen applications?#

Yes. Because Replay uses computer vision to analyze the UI, it is platform-agnostic. Whether your insurance engine is a 3270 terminal emulator, a PowerBuilder app, or an early web-based Java app, Replay can record the screen and convert the interactions into modern React code.

How much time does Replay save in a typical enterprise rewrite?#

On average, Replay reduces modernization timelines by 70%. A project that would typically take 18 months of manual discovery and coding can be completed in weeks or months. This is achieved by reducing the "time per screen" from 40 hours to just 4 hours.

Is Replay secure enough for Financial Services?#

Replay is built for highly regulated industries including Financial Services, Healthcare, and Government. It is SOC2 compliant, HIPAA-ready, and offers On-Premise installation options for organizations that require total data sovereignty.

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The Future of Modernization is Visual#

The $3.6 trillion technical debt problem won't be solved by hiring more consultants to write Jira tickets. It will be solved by automation that understands how users actually interact with software.

When you use replay detect undocumented edge cases, you aren't just building a new UI; you are recovering lost intellectual property. You are taking the rules that have governed your business for decades and finally putting them into a format that a modern engineering team can use.

Stop guessing what your legacy system does. Record it, extract it, and move on.

Ready to modernize without rewriting? Book a pilot with Replay