Delphi to React UI Refactoring: Modernizing Critical Energy Infrastructure

The power grid doesn’t care about your technical debt until the moment a 25-year-old Delphi interface freezes during a critical load-balancing event. In the energy sector, "legacy" isn't just a buzzword; it’s a liability. Thousands of SCADA systems, grid management consoles, and telemetry dashboards are still powered by Borland Delphi and the Visual Component Library (VCL). These systems are robust, but they are increasingly isolated. With a global technical debt reaching $3.6 trillion, the energy sector faces a stark choice: continue maintaining brittle, undocumented monoliths or embrace a path toward delphi react refactoring modernizing that doesn't risk a total system collapse.

The primary hurdle isn't the backend logic—which is often battle-tested Pascal—but the UI layer. These interfaces are tightly coupled to the underlying Windows OS, making web-based remote monitoring or mobile integration impossible. However, manual rewrites are notorious for their failure rates. According to Replay’s analysis, 70% of legacy rewrites fail or significantly exceed their timelines, often because the original business logic is buried in the UI event handlers.

TL;DR: Modernizing energy infrastructure from Delphi to React is no longer a "nice-to-have" due to talent scarcity and security requirements. Using Replay, enterprises can bypass the 18-month manual rewrite cycle by using Visual Reverse Engineering to convert recorded Delphi workflows directly into documented React components, reducing screen development time from 40 hours to just 4 hours.

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The High Stakes of Delphi React Refactoring Modernizing in Energy#

Energy infrastructure relies on high-fidelity, real-time data. When we talk about delphi react refactoring modernizing, we are discussing the transition from desktop-bound VCL forms to scalable, browser-based React architectures. The challenge is that 67% of these legacy systems lack any form of up-to-date documentation. The "source of truth" isn't a Confluence page; it’s the behavior of the application itself as used by a grid operator.

Video-to-code is the process of capturing these real-time user interactions and UI states through video recordings to generate structured, production-ready React code and comprehensive documentation.

For a Senior Architect, the goal is to extract the intent of the Delphi UI—the data grids, the alarm toggles, the live telemetry charts—and recreate them in a modern Design System. This is where Replay changes the math. Instead of a developer spending weeks deciphering

files and Pascal event logic, they record the application in action.

The Documentation Gap#

In many utility companies, the original developers of the Delphi systems have retired. The remaining team is often afraid to touch the UI for fear of breaking a critical validation rule hidden in a

event. Industry experts recommend a "Visual-First" approach to modernization to capture these hidden requirements before a single line of legacy code is deleted.

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

The average enterprise rewrite takes 18 months. In the energy sector, where regulatory compliance and safety are paramount, an 18-month window is a lifetime. Most of that time is wasted in the "Discovery Phase"—trying to figure out what the old system actually does.

When performing delphi react refactoring modernizing, teams usually follow a "Code-to-Code" approach. They look at the Delphi source code and try to map it to React. This is a mistake. Delphi’s state management is fundamentally different from React’s unidirectional data flow.

Replay utilizes Visual Reverse Engineering. By recording a grid operator performing a "Switchgear Maintenance" workflow, Replay's AI Automation Suite identifies the components (buttons, inputs, data tables), the layout, and the state transitions. It then generates a Component Library that mirrors the legacy functionality but uses modern React patterns.

From VCL Grids to React Data Tables#

Consider a standard Delphi

used to monitor transformer temperatures. In Delphi, this is often directly bound to a database cursor. In React, we need a functional component that handles asynchronous data streams.

Legacy Delphi Logic (Conceptual)

pascal
procedure TMainForm.UpdateTempGrid(Sender: TObject);
begin
  with TempQuery do
  begin
    Close;
    SQL.Text := 'SELECT * FROM Telemetry WHERE Status = "Active"';
    Open;
  end;
  // UI is tightly coupled to the query state
  DBGridTelemetry.Refresh;
end;

Modernized React Component (Generated via Replay)

When Replay processes the video of this grid, it generates a clean, typed React component. It separates the presentation from the data fetching logic, allowing for better testing and maintainability.

typescript
import React, { useState, useEffect } from 'react';
import { DataTable } from '@/components/ui/data-table';
import { fetchTelemetry } from '@/api/energy-api';

interface TelemetryData {
  id: string;
  transformerId: string;
  temperature: number;
  status: 'Active' | 'Warning' | 'Critical';
}

/**
 * Modernized Telemetry Grid
 * Replaced legacy TDBGrid with a responsive React component
 */
export const TelemetryMonitor: React.FC = () => {
  const [data, setData] = useState<TelemetryData[]>([]);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    const stream = fetchTelemetry().subscribe((update) => {
      setData(prev => [...prev, update]);
      setLoading(false);
    });
    return () => stream.unsubscribe();
  }, []);

  return (
    <div className="p-6 bg-slate-900 text-white rounded-lg shadow-xl">
      <h2 className="text-xl font-bold mb-4">Grid Telemetry - Real Time</h2>
      <DataTable 
        columns={columns} 
        data={data} 
        isLoading={loading}
        onRowAction={(row) => triggerMaintenanceFlow(row.id)}
      />
    </div>
  );
};

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The Replay Workflow: Modernizing Energy UI in Weeks#

The process of delphi react refactoring modernizing with Replay follows a structured path designed for regulated environments like Financial Services, Healthcare, and Energy.

1. Capture (The Library)#

The process begins by recording subject matter experts (SMEs) using the Delphi application. Replay captures every hover, click, and screen transition. This is crucial for energy systems where certain UI elements only appear during specific emergency protocols. Learn more about capturing legacy workflows.

2. Analyze (Blueprints)#

Replay’s AI analyzes the video to identify patterns. It recognizes that a specific set of Delphi panels is actually a "Dashboard Header" or a "Sidebar Navigation." The system generates Blueprints, which are the architectural skeletons of the new React application.

3. Generate (Flows)#

In the energy sector, the flow of information is more important than the look. Replay maps out the user journey. If an operator clicks "Emergency Shutdown," what screens follow? Replay documents these Flows, ensuring that the modernized React app doesn't miss a critical safety step that was hard-coded into the Delphi binary.

4. Export to React & TypeScript#

The final output is a structured React project. This isn't "spaghetti code." It’s clean, modular TypeScript that follows your organization’s specific coding standards. It includes:

• •A custom Design System based on the legacy UI.
• •Documented components.
• •State management hooks.
• •Integration points for modern APIs.

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Security and Compliance in Regulated Infrastructure#

Energy companies cannot simply upload their UI recordings to a public cloud. Replay is built for these high-stakes environments. With SOC2 compliance, HIPAA-readiness, and On-Premise deployment options, Replay ensures that sensitive grid data and proprietary workflows never leave the secure perimeter.

According to Replay's analysis, the biggest risk in delphi react refactoring modernizing is the "Security Gap"—the period during a long rewrite where the legacy system is unpatched and the new system isn't ready. By reducing the modernization timeline from 18 months to a few weeks, Replay dramatically narrows this window of vulnerability.

Comparison of Modernization Strategies#

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Technical Implementation: Handling Real-Time Telemetry#

One of the most complex aspects of delphi react refactoring modernizing for energy is the real-time nature of the data. Delphi apps often use direct socket connections or proprietary middleware. When moving to React, we typically implement a WebSockets or Server-Sent Events (SSE) architecture.

Replay helps by identifying the data update patterns in the UI. If a Delphi label flashes red when a value exceeds 100, Replay flags this as a conditional styling rule in the generated React component.

Example: Alarm Notification Component#

The following code demonstrates how a legacy Delphi alarm notification is transformed into a modern, accessible React component using the output from Replay.

typescript
import React from 'react';
import { AlertCircle, CheckCircle, Warning } from 'lucide-react';
import { cn } from '@/lib/utils'; // Tailwind utility

type AlarmSeverity = 'Critical' | 'Warning' | 'Normal';

interface AlarmProps {
  severity: AlarmSeverity;
  message: string;
  timestamp: string;
  onAcknowledge: () => void;
}

export const GridAlarm: React.FC<AlarmProps> = ({ 
  severity, 
  message, 
  timestamp, 
  onAcknowledge 
}) => {
  const styles = {
    Critical: 'bg-red-900 border-red-500 text-red-100',
    Warning: 'bg-amber-900 border-amber-500 text-amber-100',
    Normal: 'bg-emerald-900 border-emerald-500 text-emerald-100',
  };

  return (
    <div className={cn("flex items-center p-4 border-l-4 rounded shadow-md", styles[severity])}>
      <div className="mr-3">
        {severity === 'Critical' && <AlertCircle className="animate-pulse" />}
        {severity === 'Warning' && <Warning />}
        {severity === 'Normal' && <CheckCircle />}
      </div>
      <div className="flex-1">
        <p className="text-sm font-mono">{timestamp}</p>
        <p className="font-bold">{message}</p>
      </div>
      <button 
        onClick={onAcknowledge}
        className="ml-4 px-3 py-1 bg-white/10 hover:bg-white/20 rounded text-xs transition-colors"
      >
        Acknowledge
      </button>
    </div>
  );
};

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The Economic Reality of Technical Debt#

The $3.6 trillion technical debt isn't just a number on a balance sheet; it represents the millions of hours developers spend "keeping the lights on" instead of innovating. In the energy sector, this debt manifests as an inability to integrate renewable energy sources because the legacy Delphi management software can't handle the bidirectional power flow of a modern smart grid.

By choosing a path of delphi react refactoring modernizing, organizations reclaim their developer productivity. When you reduce the manual effort of screen creation from 40 hours to 4 hours, you aren't just saving money—you are gaining the agility to respond to a changing energy landscape.

Industry experts recommend that enterprise architects prioritize "High-Value, High-Risk" modules for the first phase of modernization. These are usually the screens that operators use most frequently but are the most difficult to maintain. Replay allows you to cherry-pick these workflows, record them, and generate a standalone React module that can be embedded into the legacy app or launched as a new web portal.

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Frequently Asked Questions#

Can Replay handle custom Delphi components that aren't part of the standard VCL?#

Yes. Because Replay uses Visual Reverse Engineering, it doesn't matter how the component was built in Delphi. If it appears on the screen and has a discernible behavior, Replay can capture its visual representation and functional intent to recreate it in React. This is particularly useful for energy companies using third-party telemetry libraries or custom-drawn gauges.

How does Replay ensure the generated React code matches our internal design system?#

Replay allows you to upload your existing Design System or Component Library. During the generation phase, Replay maps the identified legacy UI elements to your modern React components. If a legacy Delphi "TButton" is recorded, Replay can be configured to export it as your specific

component from your internal library.

What happens to the business logic hidden in the Pascal backend?#

Replay focuses on the UI/UX and the frontend state logic. For the heavy lifting of backend Pascal logic, we recommend a "Strangler Fig" pattern. You use Replay to build the modern React frontend, which then communicates with the legacy Pascal logic via a REST or gRPC wrapper. Over time, you can migrate the backend logic to Node.js, Go, or Python while the UI remains consistent.

Is Replay suitable for air-gapped environments common in the energy sector?#

Absolutely. Replay offers an On-Premise deployment model specifically for industries like Government, Defense, and Energy Infrastructure. This ensures that all recordings, analysis, and code generation happen within your secure, private network, satisfying the most stringent regulatory requirements.

How much time can we really save on a large-scale project?#

On average, Replay provides a 70% time savings across the entire modernization lifecycle. While a manual rewrite of a 200-screen Delphi application might take a team of ten developers 18 months, Replay can compress the UI development and documentation phase into a matter of weeks, allowing your team to focus on data integration and testing.

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Conclusion: The Future of Energy is Web-First#

The transition from Delphi to React is more than a UI upgrade; it’s a necessary evolution for the stability of our critical infrastructure. The risks of manual rewrites are too high, and the costs of doing nothing are even higher. By leveraging Visual Reverse Engineering, energy companies can preserve the institutional knowledge embedded in their legacy systems while moving to a modern, scalable, and secure React architecture.

Don't let your legacy systems become a single point of failure. With Replay, the path from a Windows-bound Delphi monolith to a cloud-native React suite is clear, documented, and significantly faster.

Ready to modernize without rewriting? Book a pilot with Replay