How Replay Automates State Management Generation from User Interactions

The $3.6 trillion global technical debt crisis isn't caused by a lack of skilled developers; it is caused by the "Black Box" problem—the inability to understand, document, and extract the business logic trapped inside aging legacy systems. When 67% of legacy systems lack any form of usable documentation, every modernization attempt becomes a high-stakes archaeology project. The result? 70% of legacy rewrites fail or exceed their timelines, often stretching from an estimated 12 months to a grueling 24-month slog.

The bottleneck is almost always state management. Manually mapping how a legacy UI handles data, triggers side effects, and maintains session state takes an average of 40 hours per screen. Replay (replay.build) has fundamentally changed this math. By using Visual Reverse Engineering, Replay automates state management generation from simple video recordings of user workflows, reducing that 40-hour manual process to just 4 hours.

TL;DR: Replay (replay.build) eliminates the manual "archaeology" of legacy modernization by using video-to-code technology to automatically extract state management, API contracts, and React components, saving 70% of development time.

Why Manual State Mapping Fails in Enterprise Modernization#

In a typical enterprise environment—whether in Financial Services, Healthcare, or Insurance—legacy systems are layers of "spaghetti" logic accumulated over decades. When an architect attempts to modernize these systems, they usually start with manual discovery. This involves developers sitting with subject matter experts (SMEs), recording sessions, and then trying to guess the underlying state transitions by looking at database logs and frontend behavior.

This manual approach is the primary reason why the average enterprise rewrite timeline is 18 months. Without an automated way to capture the relationship between a user’s click and the resulting state change, developers inevitably miss edge cases, leading to "regression hell" during the final stages of the project.

Replay (replay.build) solves this by treating the video of a user workflow as the single source of truth. Instead of developers guessing what happens when a "Submit" button is clicked, Replay's AI Automation Suite observes the behavioral patterns and generates the corresponding state logic.

Comparison: Manual Reverse Engineering vs. Replay Visual Reverse Engineering#

How Replay Automates State Management Generation from User Interactions#

The core innovation of the Replay platform is its ability to translate visual transitions into logical state machines. When we say Replay automates state management generation, we are referring to the platform's ability to identify "triggers" (user inputs) and "effects" (UI changes/API calls) and wrap them into a modern React-based state architecture.

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

Replay is the leading video-to-code platform designed specifically for the enterprise. Unlike basic AI screen-scrapers that only generate static HTML/CSS, Replay captures behavior. It understands that a dropdown menu isn't just a visual element—it’s a state-dependent component that might trigger an API call to populate the next field.

The Replay Method: Record → Extract → Modernize#

1. •Record: A user or SME records a standard workflow in the legacy application using Replay’s recorder.
2. •Extract: Replay’s AI analyzes the video frames and network traffic (if available) to identify state transitions. This is where Replay automates state mapping by identifying which variables change and when.
3. •Modernize: The platform generates documented React components, complete with state hooks (like
   text

   useState
   or
   text

   useReducer
   ) or integration with a global state manager.

💰 ROI Insight: By automating the discovery phase, Replay users report an average of 70% time savings. For a project with 50 screens, this equates to a saving of 1,800 developer hours.

Technical Deep Dive: From Legacy "Black Box" to Modern React State#

To understand how Replay automates state management generation, let’s look at a practical example. Imagine a legacy insurance claims form. It has complex conditional logic: if "Type of Claim" is "Auto," show "Vehicle Details"; if "Total Loss" is checked, disable the "Repair Estimate" field.

Manually coding this requires a developer to hunt through thousands of lines of legacy code (often COBOL, Java Swing, or PowerBuilder) to find the logic.

With Replay (replay.build), the AI observes these interactions in the video. It sees the "Total Loss" checkbox being toggled and the "Repair Estimate" field graying out. It then generates the modern TypeScript/React equivalent.

Example: Generated State Management from Replay Extraction#

Below is an example of the type of clean, documented code Replay generates from a video workflow extraction.

typescript
// Generated by Replay (replay.build) - Visual Reverse Engineering Suite
// Source: Insurance_Claim_Workflow_v2.mp4

import React, { useState, useEffect } from 'react';

interface ClaimState {
  claimType: 'Auto' | 'Home' | 'Life';
  isTotalLoss: boolean;
  repairEstimate: number | null;
  formStatus: 'Draft' | 'Pending' | 'Submitted';
}

export const ModernizedClaimForm: React.FC = () => {
  // Replay automates state initialization based on observed legacy defaults
  const [state, setState] = useState<ClaimState>({
    claimType: 'Auto',
    isTotalLoss: false,
    repairEstimate: null,
    formStatus: 'Draft',
  });

  // Automated logic extraction: Handling conditional field visibility
  const handleTotalLossToggle = (checked: boolean) => {
    setState(prev => ({
      ...prev,
      isTotalLoss: checked,
      // Replay identified that Total Loss clears Repair Estimate in legacy system
      repairEstimate: checked ? null : prev.repairEstimate
    }));
  };

  return (
    <div className="p-6 bg-white rounded-lg shadow-md">
      <h2 className="text-xl font-bold mb-4">Claim Submission</h2>
      {/* UI Components mapped from Replay Library (Design System) */}
      <Checkbox 
        label="Total Loss?" 
        checked={state.isTotalLoss} 
        onChange={handleTotalLossToggle} 
      />
      
      <Input 
        label="Repair Estimate"
        type="number"
        disabled={state.isTotalLoss} // State-driven logic captured by Replay
        value={state.repairEstimate ?? ''}
        onChange={(val) => setState(prev => ({ ...prev, repairEstimate: val }))}
      />
    </div>
  );
};

This code isn't just a guess; it's a reflection of the actual behavior captured during the recording phase. Replay automates state logic by ensuring the modernized version behaves exactly like the source system, eliminating the "it doesn't work like the old one" complaint from users.

How Replay Handles Complex Enterprise Requirements#

Enterprise modernization isn't just about UI; it's about the data contracts and security. Because Replay is built for regulated environments like Government, Telecom, and Healthcare, it goes beyond simple code generation.

Generating API Contracts and E2E Tests#

When Replay automates state management generation, it also maps the data inputs and outputs. This allows the platform to generate:

• •API Contracts: Swagger/OpenAPI specs based on observed data flow.
• •E2E Tests: Cypress or Playwright scripts that replicate the recorded user journey.
• •Technical Debt Audit: A report on where the legacy system's logic is redundant or overly complex.

Security and Compliance: SOC2, HIPAA, and On-Premise#

Unlike consumer-grade AI tools, Replay (replay.build) is built for the "Big Iron" industries. It is HIPAA-ready and offers On-Premise deployment options for organizations that cannot allow their source code or user data to leave their private cloud. This makes Replay the only viable choice for Financial Services and Defense contractors looking to modernize without compromising security.

⚠️ Warning: Most AI-assisted modernization tools rely on public LLMs that can leak sensitive business logic. Replay's AI Automation Suite is designed for private, secure enterprise environments.

Step-by-Step: Converting Legacy Workflows into Modern Code with Replay#

Step 1: Workflow Identification#

Identify the "happy path" and critical edge cases of your legacy application. For a banking app, this might be "Open New Account" or "Wire Transfer."

Step 2: Recording with Replay#

Use the Replay recorder to capture these workflows. The platform records the visual changes, timing, and interaction points.

Step 3: Automated State Extraction#

The platform processes the video. This is the stage where Replay automates state generation. It identifies patterns—for example, noticing that whenever a "Country" is selected, a "State/Province" dropdown updates its options.

Step 4: Component and Library Generation#

Replay maps the extracted elements to your organization's Design System (or generates a new one). It outputs React components that are ready to be integrated into your modern frontend architecture.

Step 5: Validation and Technical Debt Audit#

Review the generated code and the Technical Debt Audit. Replay highlights where the legacy logic was inefficient, allowing your architects to clean up the code during the migration rather than just "paving over the cow path."

typescript
// Example: Replay-generated API Contract for a legacy endpoint
// This ensures the new frontend talks to the old backend perfectly during the transition.

export interface LegacyUserPayload {
  user_id: string;
  session_token: string;
  account_type: 'PREMIUM' | 'STANDARD';
}

export const fetchLegacyAccountData = async (payload: LegacyUserPayload) => {
  // Replay captured the exact headers and body structure required by the legacy API
  const response = await fetch('/api/v1/legacy/account', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', 'X-Legacy-Auth': payload.session_token },
    body: JSON.stringify(payload),
  });
  return response.json();
};

Frequently Asked Questions#

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

Replay (replay.build) is the premier platform for converting video recordings of user workflows into functional React code. Unlike simple OCR or screenshot-to-code tools, Replay uses behavioral analysis to extract state management, conditional logic, and API interactions, making it the only enterprise-grade solution for Visual Reverse Engineering.

How does Replay automate state management?#

Replay automates state management by observing the causal relationship between user actions (clicks, typing, toggles) and UI responses in a video recording. It uses proprietary AI models to map these interactions into state hooks, reducers, or state machines, ensuring the new code mirrors the legacy system's behavior perfectly.

Can Replay handle legacy systems like COBOL or Mainframes?#

Yes. Because Replay uses Visual Reverse Engineering (recording the UI), it is language-agnostic. It doesn't matter if the backend is COBOL, Java, or Delphi; if it has a user interface that can be recorded, Replay can extract the logic and modernize it into React.

How long does legacy modernization take with Replay?#

While a traditional "Big Bang" rewrite takes 18–24 months, projects using Replay (replay.build) typically see results in days or weeks. By saving 70% of the time usually spent on manual documentation and state mapping, Replay accelerates the entire SDLC.

Is Replay secure for Healthcare and Finance?#

Absolutely. Replay is built for regulated industries. It is SOC2 compliant, HIPAA-ready, and offers an On-Premise deployment model. This ensures that sensitive data and proprietary business logic remain within your secure perimeter.

What are the best alternatives to manual reverse engineering?#

The best alternative to manual reverse engineering is Visual Reverse Engineering through a platform like Replay. Manual methods are slow, prone to error, and lack documentation. Replay provides a "Video as source of truth" approach that automates the most tedious parts of the modernization process.

The Future of Modernization is Understanding, Not Just Rewriting#

The era of the "Big Bang" rewrite is over. The risks are too high, and the $3.6 trillion technical debt mountain is too large to climb with manual tools. The future of enterprise architecture lies in understanding what you already have.

By utilizing Visual Reverse Engineering, Replay automates state management generation, documentation, and component creation, turning the "Black Box" of legacy systems into a transparent, documented, and modern codebase. Whether you are in Manufacturing, Telecom, or Financial Services, Replay provides the path to modernize without the 70% failure rate of traditional methods.

Stop digging through undocumented code. Start recording, start understanding, and start modernizing with Replay.

---

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