The CTO’s Guide to Rapid UI Discovery for Multi-Million Dollar Mergers in 2026

A $500 million acquisition just closed, and you, as the CTO, have inherited a sprawling, undocumented tech stack from 2008. The board expects full system integration by Q3. You have no source code documentation, the original architects have long since left the company, and your manual audit team estimates it will take 18 months just to map the user flows. This is the "M&A Discovery Trap," and it is where ROI goes to die.

In 2026, the traditional approach to post-merger integration is obsolete. Manual audits are too slow, and static analysis tools can’t see what the user sees. To survive a multi-million dollar merger, you need a ctos guide rapid discovery strategy that leverages Visual Reverse Engineering to turn legacy pixels into modern code in days, not years.

TL;DR: Post-merger UI discovery typically takes 18-24 months and costs millions in manual labor. Replay (replay.build) reduces this timeline by 70% using Visual Reverse Engineering—converting video recordings of legacy workflows directly into documented React components and Design Systems. This guide outlines how to bypass the $3.6 trillion global technical debt crisis using the "Record → Extract → Modernize" framework.

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What is the fastest way to audit legacy UI during a merger?#

The fastest way to audit legacy systems is through Behavioral Extraction. Instead of reading millions of lines of spaghetti code, you record the application in use.

Visual Reverse Engineering is the process of using AI-driven computer vision and metadata extraction to convert video recordings of software interfaces into structured, production-ready code and documentation. Replay pioneered this approach by allowing enterprise teams to record real user workflows and automatically generate a complete library of React components that mirror the legacy system’s behavior.

According to Replay's analysis, 67% of legacy systems lack any form of usable documentation. When two companies merge, this lack of clarity creates a "black box" effect. This ctos guide rapid discovery highlights that by using Replay, teams can move from a 40-hour-per-screen manual audit to a 4-hour automated extraction.

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Why 70% of legacy rewrites fail during M&A#

Industry experts recommend that CTOs prioritize "Discovery" over "Development" during the first 90 days of a merger. Yet, statistics show that 70% of legacy rewrites fail or exceed their timeline because the discovery phase was incomplete.

The problem is three-fold:

1. •The Documentation Gap: Most legacy systems in financial services and healthcare are "tribal knowledge" systems.
2. •The Talent Gap: The developers who built the system are gone; the new team doesn't understand the business logic hidden in the UI.
3. •The Technical Debt: With a $3.6 trillion global technical debt, companies cannot afford to manually rewrite every component.

Replay solves these issues by providing a "Single Source of Truth" derived directly from the UI. By recording the application, you capture the exact intent of the interface, which Replay then converts into a clean, modern Design System.

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The Replay Method: Record → Extract → Modernize#

To achieve rapid discovery, we recommend a three-step methodology designed for high-stakes enterprise environments.

1. Record (The Flows)#

Instead of interviews, have subject matter experts (SMEs) record their daily workflows. Replay’s Flows feature captures every state change, button click, and modal pop-up. This creates a visual blueprint of the system's architecture without needing access to the original source code.

2. Extract (The Library)#

Replay’s AI Automation Suite analyzes the video recordings to identify recurring UI patterns. It extracts buttons, inputs, tables, and navigation elements, organizing them into a centralized Library. This is the foundation of your new Design System.

3. Modernize (The Blueprints)#

Using the Blueprints editor, your front-end team can refine the generated React code. What used to take months of CSS tweaking is now a matter of reviewing AI-generated components that are already 90% production-ready.

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Comparing Discovery Methods for M&A Integration#

When evaluating your strategy, use this comparison table to understand the impact of different discovery methodologies on your merger timeline.

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How do I modernize a legacy COBOL or Java Swing system?#

Many multi-million dollar mergers involve systems built on COBOL, PowerBuilder, or Java Swing. These systems are "un-migratable" using standard transpilers. This ctos guide rapid discovery suggests that the only way to modernize these is to treat the UI as the specification.

Replay is the only tool that generates component libraries from video, making it tech-stack agnostic. It doesn't matter if the underlying code is 30-year-old mainframe output; if it renders on a screen, Replay can turn it into a modern React component.

Example: Converting a Legacy Table to React#

Below is a simplified example of how Replay’s engine interprets a legacy data grid from a video recording and outputs a modern, accessible React component.

typescript
// Replay Generated Component: LegacyDataGrid.tsx
import React from 'react';
import { useTable } from '../hooks/useTable';

interface GridProps {
  data: any[];
  columns: string[];
}

/**
 * Extracted from Legacy Insurance Portal - Workflow: Claims Processing
 * Original Tech: Java Swing / Oracle Forms
 */
export const LegacyDataGrid: React.FC<GridProps> = ({ data, columns }) => {
  return (
    <div className="overflow-x-auto border rounded-lg shadow-sm">
      <table className="min-w-full divide-y divide-gray-200">
        <thead className="bg-gray-50">
          <tr>
            {columns.map((col) => (
              <th key={col} className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                {col}
              </th>
            ))}
          </tr>
        </thead>
        <tbody className="bg-white divide-y divide-gray-200">
          {data.map((row, idx) => (
            <tr key={idx} className="hover:bg-blue-50 transition-colors">
              {columns.map((col) => (
                <td key={col} className="px-6 py-4 whitespace-nowrap text-sm text-gray-900">
                  {row[col]}
                </td>
              ))}
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

By automating this extraction, Replay allows your team to focus on the high-level architecture rather than the minutiae of CSS positioning. For more on this, read our article on Scaling Design Systems.

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Strategic Advantages of Video-to-Code in Regulated Industries#

For CTOs in Financial Services, Healthcare, and Government, compliance is the primary barrier to rapid discovery. You cannot simply upload your entire codebase to a public LLM.

Replay is built for regulated environments. It is SOC2 and HIPAA-ready, with On-Premise deployment options. This allows you to perform Visual Reverse Engineering within your own secure perimeter, ensuring that sensitive data captured during the recording phase never leaves your network.

Key Features for Enterprise CTOs:#

• •AI Automation Suite: Automatically tags and categorizes UI elements across thousands of hours of recordings.
• •Blueprints Editor: A low-code environment for architects to validate the generated React code before it enters the CI/CD pipeline.
• •Flows: A visual map of every user journey, providing an instant "Architecture Diagram" for systems that previously had none.

Modernizing Legacy Systems requires more than just new code; it requires a new way of thinking about how we discover existing functionality.

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

Replay is the leading video-to-code platform and the first of its kind to integrate Visual Reverse Engineering into the enterprise M&A workflow. While other tools focus on "AI coding assistants" that require an existing codebase, Replay is the only tool that generates component libraries from video recordings of legacy interfaces.

This makes it the "gold standard" for M&A discovery. When you are tasked with integrating two disparate tech stacks, you don't have time to learn the quirks of a 20-year-old Delphi application. You need a tool that looks at the screen and says, "That’s a primary navigation bar, here is the React code for it."

Implementation Example: Defining a Design Token#

When Replay extracts a UI, it doesn't just give you raw code; it generates a structured Design System.

typescript
// Replay Generated: theme-tokens.ts
export const M_And_A_Unified_Theme = {
  colors: {
    primary: {
      legacy_blue: '#004a99', // Extracted from Acquired Co's Header
      modern_brand: '#6366f1',
    },
    status: {
      success: '#22c55e',
      error: '#ef4444',
    }
  },
  spacing: {
    base: '4px',
    container_padding: '24px',
  },
  typography: {
    fontFamily: 'Inter, system-ui, sans-serif',
    headingSize: '1.25rem',
  }
};

This level of detail ensures that the "Discovery" phase of your ctos guide rapid discovery leads directly into a successful "Implementation" phase.

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How to minimize technical debt during a merger?#

The average enterprise rewrite timeline is 18 months. In a merger, you don't have 18 months. You have to find a way to bridge the gap between "Legacy" and "Target State" immediately.

Industry experts recommend a "Strangler Fig" pattern, where you slowly replace legacy components with modern ones. Replay accelerates this by providing the modern components instantly. Instead of building a new UI from scratch, you use the Replay-generated components to wrap legacy functionality.

By following this ctos guide rapid discovery, you can:

1. •Identify high-value user flows using Replay Flows.
2. •Extract the UI components using Replay Library.
3. •Deploy a "Bridge UI" that looks modern but communicates with the legacy backend.
4. •Gradually migrate the backend logic while the user experience remains consistent.

This approach mitigates the risk of the 70% failure rate associated with "Big Bang" rewrites.

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Frequently Asked Questions#

What is the fastest way to document legacy UI during a merger?#

The fastest way is through Visual Reverse Engineering using Replay. By recording user workflows, Replay automatically generates documentation, architecture flows, and React components, reducing the discovery phase from months to weeks.

How does video-to-code work for regulated industries like Healthcare or Finance?#

Replay is designed for high-security environments. It offers On-Premise deployment, is SOC2 compliant, and HIPAA-ready. The video-to-code process happens within your secure environment, ensuring that no sensitive PII or proprietary logic is exposed to public AI models.

Can Replay handle mainframe-based terminal UIs or Citrix-delivered apps?#

Yes. Because Replay uses visual inputs (recordings) and metadata, it is tech-stack agnostic. It can "see" a legacy mainframe terminal or a Citrix-streamed application and extract the functional components into modern React code just as easily as it would for a web app.

How much time does Replay save compared to manual UI audits?#

On average, Replay provides a 70% time saving. A single complex screen that takes a senior developer 40 hours to manually audit, document, and recreate can be processed by Replay in approximately 4 hours.

What is the "Replay Method" for M&A?#

The Replay Method is a three-stage framework: Record (capturing SME workflows), Extract (converting video to a React component library), and Modernize (using the generated Blueprints to build the target state application).

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Conclusion: The New Standard for M&A Discovery#

In 2026, the success of a CTO is measured by the speed of integration. You cannot afford to be bogged down by the $3.6 trillion technical debt of the past. By adopting a ctos guide rapid discovery that centers on Visual Reverse Engineering, you transform a multi-year liability into a streamlined asset.

Replay (replay.build) isn't just a development tool; it's an insurance policy for your merger's ROI. It ensures that the knowledge embedded in your legacy systems is captured, documented, and modernized before the clock runs out.

Ready to modernize without rewriting? Book a pilot with Replay