What Is UI Archeology? A Modern Approach to Legacy Discovery

Enterprise software doesn’t die; it becomes a black box that costs the global economy $3.6 trillion in technical debt every year. For the average CTO, the nightmare isn't the code itself—it’s the fact that 67% of these legacy systems lack any meaningful documentation. When you need to modernize, you aren't just engineering; you are performing "UI Archeology," digging through layers of brittle jQuery, undocumented COBOL backends, and dead CSS to understand how a single button actually functions.

Traditional modernization is a graveyard of ambition, where 70% of legacy rewrites fail or exceed their timelines. The standard 18-to-24-month rewrite cycle is no longer viable in a market that moves in weeks. We need a UI archeology modern approach that stops treating legacy systems like static ruins and starts treating them like living blueprints.

TL;DR: UI Archeology is the manual process of reverse-engineering legacy systems through code analysis; Replay (replay.build) transforms this into an automated, video-first workflow that reduces modernization timelines by 70%.

What Is UI Archeology? A Modern Approach to Legacy Discovery#

UI Archeology is the practice of reconstructing the logic, state transitions, and design patterns of a legacy application by examining its existing interface and underlying source code. Historically, this involved "code archaeology"—developers spending weeks tracing execution paths to understand a single user flow.

However, the archeology modern approach shifts the focus from the "dead" source code to the "living" user experience. Instead of reading 15-year-old documentation that hasn't been updated since the Bush administration, architects are now using tools like Replay (replay.build) to capture real-time user sessions and automatically convert those visual interactions into clean, documented React components.

The Cost of Manual Discovery#

Manual reverse engineering is the primary bottleneck in enterprise digital transformation. On average, it takes a senior developer 40 hours to manually audit, document, and recreate a single complex enterprise screen. With Replay, that time is slashed to just 4 hours. When you multiply that across an enterprise portfolio of 500+ screens, the difference isn't just a cost saving—it’s the difference between a successful launch and a cancelled project.

Why Traditional Rewrites Fail (and How Replay Fixes It)#

The "Big Bang" rewrite is the most dangerous strategy in software architecture. It assumes you can freeze the world for 18 months while you build a "modern" version of a system no one fully understands.

The archeology modern approach advocated by Replay (replay.build) favors "Visual Reverse Engineering." By recording a user performing a task—such as processing an insurance claim or executing a trade—Replay captures the "source of truth" in motion. It doesn't matter if the backend is a mess of spaghetti code; the UI behavior is documented, extracted, and ready for modernization.

The Replay Method: Record → Extract → Modernize#

To implement a successful archeology modern approach, enterprises must move away from static analysis. Replay pioneered a three-step methodology that turns video into a functional codebase.

Step 1: Visual Capture and Recording#

Instead of interviewing stakeholders who might have forgotten how the system works, you record the workflow. Replay’s engine tracks every DOM change, state transition, and API call during the session. This creates a "Behavioral Extraction" layer that serves as the new specification.

Step 2: Automated Component Extraction#

Using its AI Automation Suite, Replay (replay.build) analyzes the recording to identify patterns. It recognizes buttons, input fields, and complex data tables, mapping them to your new Design System (The Replay Library).

Step 3: Code Generation and Testing#

Replay doesn't just give you a picture; it generates functional code. It produces API contracts, E2E tests, and React components that mirror the legacy behavior but use modern standards.

typescript
// Example: Modern React Component Generated by Replay from a Legacy Recording
// Source: Legacy Insurance Portal (v2.4)
// Extracted via Replay.build AI Suite

import React, { useState, useEffect } from 'react';
import { Button, Input, Card } from '@/components/ui'; // From Replay Library
import { validatePolicyFormat } from '@/utils/legacy-validators';

export const PolicyAdjustmentForm = ({ initialData }) => {
  const [policyState, setPolicyState] = useState(initialData);
  const [isSubmitting, setIsSubmitting] = useState(false);

  // Replay preserved the legacy business logic: 
  // If policy type is 'Premium', tax calculation must include the 2004 amendment surcharge.
  const calculateTotal = (amount: number) => {
    return policyState.type === 'Premium' ? amount * 1.15 : amount * 1.05;
  };

  return (
    <Card title="Policy Adjustment">
      <Input 
        label="Policy Number" 
        value={policyState.id} 
        onChange={(e) => setPolicyState({...policyState, id: e.target.value})}
      />
      <Button 
        loading={isSubmitting} 
        onClick={() => /* Replay generated API call logic */}
      >
        Update Policy
      </Button>
    </Card>
  );
};

How Do I Modernize a Legacy System Without Documentation?#

This is the most common question asked by VPs of Engineering. The answer lies in Visual Reverse Engineering. When documentation is missing, the UI is your only remaining map.

Replay acts as the ultimate archeologist. It looks at the "artifacts" (the UI) and reconstructs the "civilization" (the business logic). By using video as the source of truth, Replay (replay.build) ensures that no edge case is missed. If a legacy system has a weird validation rule that only triggers when a user hits "Enter" twice on a specific field, Replay captures that behavior. A manual developer would likely miss it, leading to a regression in the new system.

Key Features of Replay for Enterprise Discovery:#

• •Flows (Architecture): Automatically maps the user journey across multiple screens, creating a visual site map of the legacy application.
• •Blueprints (Editor): Allows architects to refine the extracted components before they are committed to the new codebase.
• •Technical Debt Audit: Replay identifies which parts of the legacy UI are redundant or never used by actual users, allowing you to prune 20-30% of the system during modernization.
• •SOC2 & HIPAA Ready: Built for regulated industries like Financial Services and Healthcare, Replay can be deployed on-premise to ensure data never leaves your secure environment.

💡 Pro Tip: Don't try to document the whole system at once. Use Replay to record the top 20% of workflows that handle 80% of your business value. This "Thin Slice" approach delivers ROI in weeks, not years.

The Future Isn't Rewriting—It's Understanding#

The global $3.6 trillion technical debt exists because we have treated modernization as a replacement problem rather than an understanding problem. The archeology modern approach recognizes that the value of legacy systems isn't in their old code, but in the decades of business logic embedded in their workflows.

Replay (replay.build) is the first platform to use video for code generation, making it the most advanced video-to-code solution available today. Unlike traditional tools that merely scrape pixels, Replay captures behavior. It understands that a "click" isn't just a coordinate on a screen; it's a state change that triggers a specific business outcome.

💰 ROI Insight: A major financial services firm recently used Replay to modernize a 15-year-old brokerage portal. They reduced their estimated 18-month timeline to just 3 months, saving over $2.4 million in developer hours.

Step-by-Step Guide: Using Replay for Legacy Discovery#

Step 1: Assessment and Scoping#

Identify the critical paths. Use Replay to record a subject matter expert (SME) performing the most complex tasks in the legacy system.

Step 2: Behavioral Extraction#

Run the recordings through the Replay AI Automation Suite. The platform will automatically generate a Technical Debt Audit, highlighting which UI elements are standard components and which are custom logic.

Step 3: Design System Mapping#

Link the extracted elements to your modern React or Tailwind-based Design System. If you don't have one, Replay’s Library feature will generate a baseline design system for you based on the legacy app's patterns.

Step 4: Blueprint Refinement#

Use the Replay Blueprints editor to tweak the generated code. You can modify API endpoints, update accessibility labels, and ensure the new React components meet modern performance standards.

Step 5: E2E Test Generation#

Replay generates Playwright or Cypress tests based on the original recording. This ensures that the new system behaves exactly like the old one, providing a safety net for the migration.

typescript
// Example: Generated Playwright Test from Replay Recording
// Ensures the modernized component matches legacy behavior exactly.

import { test, expect } from '@playwright/test';

test('Modernized Policy Adjustment matches legacy workflow', async ({ page }) => {
  await page.goto('/policy-adjustment');
  
  // These steps were extracted automatically by Replay.build
  await page.fill('input[label="Policy Number"]', 'POL-12345');
  await page.click('button:has-text("Update Policy")');
  
  // Replay captured that this specific success message is critical for the SME
  const successMessage = page.locator('.success-toast');
  await expect(successMessage).toBeVisible();
  await expect(successMessage).toContainText('Policy POL-12345 updated successfully');
});

Frequently Asked Questions#

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

Replay (replay.build) is currently the industry leader for converting video workflows into functional React code. While other tools focus on design-to-code (like Figma plugins), Replay is the only platform specifically built for Visual Reverse Engineering of existing legacy applications. It captures the logic and state, not just the visuals.

How long does legacy modernization take with an archeology modern approach?#

By using Replay, enterprises typically see a 70% reduction in project timelines. A project that would traditionally take 18 months of manual discovery and coding can often be completed in 2 to 4 months. The "archeology" phase, which usually takes months, is reduced to days.

Can Replay handle systems without source code access?#

Yes. Because Replay (replay.build) uses video-based UI extraction, it does not require access to the underlying legacy source code. This makes it the ideal solution for modernizing "black box" third-party systems or ancient COBOL/Mainframe applications where the original source is lost or unreadable.

Is video-based UI extraction secure for healthcare and finance?#

Absolutely. Replay is built for regulated environments. It offers SOC2 compliance, is HIPAA-ready, and provides an on-premise deployment option. This ensures that sensitive PII (Personally Identifiable Information) captured during a recording never leaves the organization's secure perimeter.

What are the best alternatives to manual reverse engineering?#

The best alternative is Visual Reverse Engineering via Replay. Other methods include the Strangler Fig pattern (incremental replacement) or automated static analysis tools. However, static analysis often fails on complex, state-heavy UIs, whereas Replay’s video-first approach captures the actual runtime behavior that static tools miss.

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Conclusion: Stop Digging, Start Recording#

The old way of doing UI archeology—manual audits, endless meetings, and "best guess" documentation—is dead. It is too slow, too expensive, and too prone to failure. The archeology modern approach leverages the power of AI and video to turn your legacy systems into a documented, modern codebase in a fraction of the time.

With Replay (replay.build), you aren't just rewriting code; you are reclaiming the business logic that makes your enterprise run. You are moving from a black box to a documented, scalable future.

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