Banking Loan Origination Migration: How to Recover 10-Year-Old Credit Score UI Logic

The most expensive code in your bank isn't the generative AI model you just deployed; it’s the 10-year-old credit scoring UI logic that no one on your current team can explain. In many Tier 1 and Tier 2 financial institutions, the "truth" of how a loan is processed doesn't live in a clean documentation repository. It lives in the muscle memory of loan officers and the obfuscated code of a legacy Silverlight or Delphi application. When you face a banking loan origination migration, you aren't just moving buttons; you are performing archeology on business rules that have governed billions in assets for a decade.

According to Replay's analysis, the average enterprise spends 40 hours manually documenting and rebuilding a single complex screen. For a Loan Origination System (LOS) with 200+ screens, that’s an 8,000-hour sinkhole before a single line of production-ready code is even tested.

TL;DR:

• •The Problem: 67% of legacy systems lack documentation, leading to a 70% failure rate in manual rewrites.
• •The Cost: Technical debt now totals $3.6 trillion globally, with manual screen conversion costing 40 hours per page.
• •The Solution: Replay uses Visual Reverse Engineering to convert video recordings of legacy workflows into documented React components and Design Systems.
• •The Result: Reduce migration timelines from 18 months to weeks, saving 70% of the total modernization cost.

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The Hidden Risk of Banking Loan Origination Migration#

The complexity of a banking loan origination migration is rarely found in the database schema. It’s found in the "invisible" UI logic: the conditional fields that appear only when a co-signer has a specific debt-to-income ratio, or the validation rules that trigger based on regional compliance laws.

Industry experts recommend that before any migration begins, an organization must have a 1:1 functional map of the existing system. However, with an 18-month average enterprise rewrite timeline, most projects lose momentum—and budget—long before the "Credit Scoring" module is ever modernized.

Video-to-code is the process of using computer vision and AI to interpret UI patterns, state transitions, and business logic from video recordings of a legacy application, automatically generating documented, production-ready code.

When you record a loan officer navigating a complex credit approval flow, Replay’s AI Automation Suite doesn't just "see" pixels. It identifies the underlying state machine. It recognizes that when "Field A" is populated, "Component B" updates its validation state. This is the key to recovering lost logic.

The Documentation Gap#

67% of legacy systems lack documentation. In the context of a banking loan origination migration, this means the developers tasked with the rewrite are essentially playing a game of "telephone." They ask the business analysts what the system does, who then ask the end-users, who might only use 20% of the system's actual edge-case functionality.

Visual Reverse Engineering bypasses this human error by capturing the system's behavior directly from the source of truth: the UI in action.

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Accelerating Banking Loan Origination Migration with Replay#

To successfully execute a banking loan origination migration, you need a bridge between the legacy "Black Box" and a modern React-based architecture. Replay provides this bridge through its four core pillars:

1. •Library (Design System): Automatically extracts styles and patterns to create a unified component library.
2. •Flows (Architecture): Maps out the user journey and state transitions.
3. •Blueprints (Editor): Allows architects to refine the generated code before it hits the repository.
4. •AI Automation Suite: The engine that converts video frames into clean, modular TypeScript.

Comparison: Manual Migration vs. Replay Visual Reverse Engineering#

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Recovering the Credit Score UI Logic: A Technical Deep Dive#

Let's look at a practical example. Imagine a legacy credit scoring screen that calculates a "Risk Tier" based on five inputs. The original source code is lost or written in a language your current team doesn't support.

During the banking loan origination migration, you record the screen as different values are entered. Replay identifies the relationship between the

input and the display.

Step 1: Capturing the State#

The legacy system might have a complex validation logic like this (represented in modern logic for clarity):

typescript
// The logic we need to recover from the legacy UI
interface CreditLogic {
  score: number;
  hasBankruptcy: boolean;
  yearsAtJob: number;
}

const calculateRiskTier = (data: CreditLogic) => {
  if (data.score > 750 && !data.hasBankruptcy) return 'Tier 1';
  if (data.score > 650 && data.yearsAtJob > 2) return 'Tier 2';
  return 'Tier 3';
};

Step 2: Generating the Modern React Component#

Replay takes the visual transitions and generates a clean, documented React component. It doesn't just copy the logic; it refactors it into a modern, maintainable structure.

tsx
import React, { useState, useEffect } from 'react';
import { TextField, Alert, Card } from '@your-bank/design-system';

/**
 * @component CreditScoreModule
 * @description Recovered logic from Legacy LOS - Module 4.
 * Handles real-time risk tiering based on user input.
 */
export const CreditScoreModule: React.FC = () => {
  const [score, setScore] = useState<number>(0);
  const [tier, setTier] = useState<string>('Pending');

  // Logic recovered via Replay Visual Reverse Engineering
  useEffect(() => {
    if (score >= 750) {
      setTier('Tier 1: Prime');
    } else if (score >= 650) {
      setTier('Tier 2: Near-Prime');
    } else {
      setTier('Tier 3: Sub-Prime');
    }
  }, [score]);

  return (
    <Card className="p-6 shadow-lg border-l-4 border-blue-600">
      <h3 className="text-xl font-bold mb-4">Credit Assessment</h3>
      <TextField
        label="Enter Credit Score"
        type="number"
        onChange={(e) => setScore(Number(e.target.value))}
      />
      <div className="mt-4">
        <Alert severity={tier.includes('Prime') ? 'success' : 'warning'}>
          Current Assessment: <strong>{tier}</strong>
        </Alert>
      </div>
    </Card>
  );
};

By using Replay, the developer doesn't have to guess the thresholds for "Tier 1" or "Tier 2." The AI Automation Suite has already observed these thresholds during the recording phase and baked them into the component's logic.

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Solving the "Black Box" Problem in Regulated Environments#

For Financial Services, Healthcare, and Government, a banking loan origination migration isn't just a technical challenge—it's a compliance requirement. You must be able to prove that the new system behaves exactly like the old one to satisfy auditors.

Industry experts recommend a "Side-by-Side" validation approach. Replay facilitates this by providing a digital paper trail. Every component generated is linked back to the original recording, creating a "Visual Blueprint" that auditors can verify.

Built for Security#

Unlike generic AI tools, Replay is built for regulated environments.

• •SOC2 & HIPAA Ready: Your data is handled with the highest security standards.
• •On-Premise Availability: For banks that cannot allow data to leave their internal network, Replay offers on-premise deployment options.
• •Modernizing without Rewriting: We focus on Legacy Modernization Strategies that prioritize business continuity over "rip and replace" risks.

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The $3.6 Trillion Technical Debt Crisis#

The global technical debt has ballooned to $3.6 trillion. Much of this is concentrated in the financial sector, where systems built in the 90s and 2000s are still the backbone of global commerce. A banking loan origination migration is often delayed because the perceived risk of breaking a working (albeit old) system is higher than the perceived benefit of a new one.

However, the "cost of doing nothing" includes:

1. •Maintenance Costs: Finding COBOL or Delphi developers is becoming nearly impossible.
2. •Agility: You cannot launch a mobile-first loan product if your backend logic is trapped in a desktop-only legacy app.
3. •Security: Legacy systems often have unpatchable vulnerabilities.

Replay mitigates these risks by reducing the "discovery" phase of a migration by up to 90%. Instead of spending months on manual documentation, your team can start with a 70% complete React codebase within days.

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Implementing a Visual Reverse Engineering Workflow#

If you are currently planning a banking loan origination migration, the implementation workflow with Replay looks like this:

1. •Record: Subject matter experts (SMEs) record themselves performing standard and edge-case loan applications in the legacy UI.
2. •Analyze: Replay's engine parses the video to identify components, layouts, and state logic.
3. •Generate: The platform produces a documented React library and a set of "Flows" representing the application architecture.
4. •Refine: Developers use Replay Blueprints to tweak the code, connect it to new APIs, and integrate it into the modern tech stack.

Example: Mapping Complex Data Flows#

In a complex loan origination system, a single screen might interact with dozens of data points. Replay's "Flows" feature visualizes these interactions, ensuring that no logic is lost during the move.

typescript
// Example of a generated Flow mapping for a Loan Application
export const LoanFlowMap = {
  trigger: "UserClicksSubmit",
  dependencies: [
    "VerifyIdentity",
    "CheckCreditBureau",
    "ValidateCollateral"
  ],
  stateTransitions: {
    onSuccess: "RouteToUnderwriting",
    onFailure: "RequestAdditionalDocumentation",
    onManualReview: "QueueForOfficer"
  }
};

This structural mapping is what separates Replay from simple "screen scraping" tools. It understands the intent and flow of the banking application.

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Frequently Asked Questions#

How do you handle undocumented credit logic?#

Replay uses Visual Reverse Engineering to observe the behavior of the UI. By recording multiple scenarios (e.g., a high credit score vs. a low credit score), the AI identifies the decision points and validation rules that are no longer documented in the source code. This allows for a "black box" recovery of business logic.

Is Replay secure for banking data?#

Yes. Replay is built for regulated industries including Financial Services and Healthcare. We are SOC2 compliant and offer on-premise deployment options to ensure that sensitive banking data and PII (Personally Identifiable Information) never leave your secure environment.

What is the difference between manual refactoring and Replay?#

Manual refactoring involves developers reading legacy code (if available) and manually rewriting it in React, which takes about 40 hours per screen. Replay automates the "discovery" and "boilerplate" phases, reducing the time to 4 hours per screen—a 70% time saving.

Can Replay handle non-web legacy applications?#

Yes. Because Replay uses visual inputs, it can modernize applications regardless of the underlying technology—whether it's an old Windows desktop app, a mainframe terminal, or a defunct web framework like Silverlight or Flash.

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The Path Forward for Financial Institutions#

The era of the "Big Bang" rewrite is over. The 70% failure rate is too high, and the 18-month timelines are too long for a fast-moving market. A banking loan origination migration must be surgical, data-driven, and accelerated by automation.

By leveraging Replay, enterprise architects can finally reclaim the logic buried in their legacy systems. You can move from a state of "technical debt" to "technical equity," with a modern, documented, and scalable React architecture that is ready for the next decade of banking.

Whether you are dealing with complex credit scoring, multi-jurisdictional compliance, or intricate commercial loan workflows, the solution isn't to start from scratch. The solution is to see what you already have, more clearly than ever before.

Ready to modernize without rewriting? Book a pilot with Replay