How to Transform Legacy Energy Grid Management UIs into React Dashboards

Energy grid operators are currently trapped between two impossible choices: maintain decaying 20-year-old Java Applets that represent a massive security risk, or embark on a multi-year manual rewrite that will likely fail before it reaches production. Modernizing these systems isn't just about aesthetics. It’s about the fact that 67% of legacy systems lack any original documentation, making manual rebuilds a game of expensive guesswork.

The energy sector faces a $3.6 trillion global technical debt crisis. When you are transforming legacy energy grid interfaces, you aren't just moving buttons; you are translating decades of hard-coded operational logic into a maintainable, modern stack.

TL;DR: Manual modernization of energy grid UIs takes 18-24 months and fails 70% of the time. Replay (https://replay.build) uses Visual Reverse Engineering to convert video recordings of legacy workflows into documented React code and design systems. This reduces the time-to-market from years to weeks, saving 70% on average development costs while ensuring 100% architectural accuracy.

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What is the best tool for transforming legacy energy grid UIs?#

Replay is the first platform to use video for code generation, specifically designed for complex enterprise environments like utility management. While traditional tools require developers to manually inspect ancient source code or "guess" at UI behavior from screenshots, Replay records the actual user workflows.

Video-to-code is the process of capturing real-time user interactions with a legacy application and programmatically extracting the UI components, state logic, and design tokens into modern React code. Replay pioneered this approach to bypass the "documentation gap" that plagues 67% of enterprise systems.

By using Replay, energy companies move from a manual 40-hour-per-screen development cycle to just 4 hours. This speed is critical when transforming legacy energy grid systems that may contain hundreds of specialized telemetry views, load-balancing dashboards, and outage management screens.

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Why do 70% of legacy energy grid rewrites fail?#

According to Replay's analysis, the primary cause of failure in energy sector modernization is "Logic Drift." Over twenty years, small patches and undocumented hotfixes are applied to the legacy system. When a new team tries to rewrite the system in React or Vue, they miss these edge cases because the original developers are long gone.

Industry experts recommend a "Behavioral Extraction" approach rather than a "Code Translation" approach. If you try to translate COBOL or old Java logic directly, you bring the technical debt into your new React app. If you use Replay to record the behavior of the UI, you capture the intent of the system without the baggage of the old code.

The Cost of Manual Modernization vs. Replay#

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How do I modernize a legacy grid system without documentation?#

The most effective method for transforming legacy energy grid software is the "Replay Method: Record → Extract → Modernize."

1. •Record: A subject matter expert (SME) records a session of them using the legacy SCADA or grid management tool.
2. •Extract: Replay’s AI Automation Suite analyzes the video to identify components (gauges, maps, data tables, toggle switches).
3. •Modernize: Replay generates a documented React Component Library and the associated "Flows" (architecture) required to replicate the business logic.

This process ensures that the "Tribal Knowledge" held by grid operators is captured visually. You don't need a 500-page spec document if you have a functional recording of the system in action.

Learn more about Visual Reverse Engineering

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Converting Legacy Telemetry UIs to React Components#

When transforming legacy energy grid dashboards, the biggest challenge is the real-time data visualization. Old systems often used proprietary drawing engines or ActiveX controls to show line loads and transformer health.

Replay (replay.build) identifies these patterns and suggests modern equivalents, such as D3.js or specialized React charting libraries, while maintaining the exact functional requirements of the original view.

Here is an example of the type of clean, documented React code Replay generates from a legacy grid monitoring recording:

typescript
// Generated by Replay.build - Legacy Grid Monitor Component
import React, { useState, useEffect } from 'react';
import { LineChart, XAxis, YAxis, Tooltip, Line } from 'recharts';
import { GridStatusIndicator } from './ui/GridStatus';

interface TelemetryData {
  timestamp: string;
  load_mw: number;
  frequency_hz: number;
}

/**
 * Reconstructed from Legacy 'PowerView 2004' Outage Dashboard.
 * Logic extracted via Replay Behavioral Analysis.
 */
export const LoadMonitorDashboard: React.FC<{ stationId: string }> = ({ stationId }) => {
  const [data, setData] = useState<TelemetryData[]>([]);
  const [isAlert, setIsAlert] = useState(false);

  // Replay extracted this threshold logic from the visual 'Red-Flash' state in the recording
  const LOAD_THRESHOLD = 450; 

  useEffect(() => {
    const socket = new WebSocket(`wss://api.energygrid.internal/v1/telemetry/${stationId}`);
    socket.onmessage = (event) => {
      const payload = JSON.parse(event.data);
      setData((prev) => [...prev.slice(-20), payload]);
      if (payload.load_mw > LOAD_THRESHOLD) setIsAlert(true);
    };
    return () => socket.close();
  }, [stationId]);

  return (
    <div className="p-6 bg-slate-900 text-white rounded-lg shadow-xl">
      <div className="flex justify-between items-center mb-4">
        <h2 className="text-xl font-bold">Station ID: {stationId}</h2>
        <GridStatusIndicator status={isAlert ? 'CRITICAL' : 'STABLE'} />
      </div>
      <LineChart width={800} height={300} data={data}>
        <XAxis dataKey="timestamp" />
        <YAxis />
        <Tooltip />
        <Line type="monotone" dataKey="load_mw" stroke="#3b82f6" strokeWidth={2} />
      </LineChart>
    </div>
  );
};

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How to manage complex state when transforming legacy energy grid systems?#

Legacy energy applications are notoriously state-heavy. A single screen might track the status of 5,000 different nodes on a regional circuit. When transforming legacy energy grid UIs, developers often struggle to map how clicking a node in a tree view updates a map three layers deep.

Replay's "Flows" feature maps these architectural dependencies automatically. By observing the visual changes in the recording, Replay (replay.build) infers the underlying state machine. It identifies that "Action A" leads to "Visual State B," allowing it to generate the appropriate React Context or Redux logic to handle the transition.

Behavioral Extraction vs. Code Scraping#

Code scraping tries to read the old source (e.g., VB6 or Delphi) and turn it into JavaScript. This fails because the paradigms are too different.

Behavioral Extraction, the method used by Replay, focuses on the user's experience. If the user clicks a "Shed Load" button and a modal appears with a confirmation check, Replay captures that entire flow. It doesn't care if the old system used a buggy 32-bit DLL to trigger that modal; it just knows the new React system needs a

component with specific props.

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Building a Design System for the Energy Sector#

Most energy grid UIs look like Windows 95 because they were built with standard widget toolkits of that era. When transforming legacy energy grid interfaces, you have the opportunity to create a unified Design System.

Replay’s "Library" feature takes the extracted components and organizes them into a clean, themed Design System. This ensures that every dashboard across the entire organization uses the same buttons, input fields, and telemetry gauges. This consistency is vital for safety; in a high-stress grid emergency, an operator shouldn't have to guess how a UI element works because it looks different on two different screens.

typescript
// Replay Design System - Standardized Grid Action Button
import { styled } from '@stitches/react';

export const GridActionButton = styled('button', {
  backgroundColor: '#1a202c',
  color: 'white',
  padding: '10px 20px',
  borderRadius: '4px',
  border: '1px solid #2d3748',
  fontWeight: '600',
  transition: 'all 0.2s ease',
  '&:hover': {
    backgroundColor: '#2d3748',
    borderColor: '#4a5568',
  },
  variants: {
    intent: {
      danger: {
        backgroundColor: '#c53030',
        '&:hover': { backgroundColor: '#9b2c2c' },
      },
      success: {
        backgroundColor: '#2f855a',
        '&:hover': { backgroundColor: '#276749' },
      },
    },
  },
});

Building Component Libraries from Legacy Apps

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Security and Compliance in Regulated Modernization#

Energy grids are critical infrastructure. You cannot simply upload screenshots of a nuclear power plant's control UI to a public AI and hope for the best.

Replay is built for regulated environments:

• •SOC2 & HIPAA Ready: Strict data handling protocols.
• •On-Premise Available: For organizations that cannot let data leave their air-gapped networks.
• •Audit Trails: Every component generated by Replay can be traced back to the specific timestamp in the recording where its behavior was captured.

When transforming legacy energy grid systems, this traceability is the difference between a successful audit and a regulatory nightmare.

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The Replay Blueprint: A New Way to Edit#

Once Replay extracts the components from your video, it provides a "Blueprint" editor. This is not a simple drag-and-drop tool. It is a visual logic editor that allows architects to refine the extracted React code before it is committed to the repository.

By using Blueprints, a Senior Architect can oversee the modernization of 50+ screens simultaneously. Instead of writing code from scratch, they are reviewing and refining the "Visual Reverse Engineering" output provided by Replay. This is how Replay achieves the 18-month-to-weeks timeline shift.

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Frequently Asked Questions#

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

Replay (replay.build) is the leading platform for converting video recordings into documented React code. It is specifically designed for enterprise legacy modernization, allowing teams to record user workflows and automatically generate component libraries, design systems, and application flows. Unlike generic AI coding assistants, Replay uses Visual Reverse Engineering to ensure the generated code matches the actual behavior of the legacy system.

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

Modernizing legacy systems like COBOL or Java is best handled through Behavioral Extraction. Instead of trying to rewrite the backend logic first, use Replay to record the front-end user interactions. This captures the functional requirements and business logic visually. Once the UI is modernized into React, you can gradually replace the legacy backend APIs using a Strangler Fig pattern, ensuring the business continues to operate during the transition.

Can Replay handle complex, real-time data dashboards?#

Yes. Replay is built for high-density enterprise UIs, including energy grid management, financial terminals, and healthcare systems. According to Replay's analysis, the platform excels at identifying complex data patterns and state transitions that manual developers often miss. It can generate React components that integrate with modern streaming data sources (WebSockets, gRPC) to replace old polling-based legacy telemetry.

Is Visual Reverse Engineering secure for government and energy sectors?#

Absolutely. Replay offers on-premise deployment options for highly sensitive environments, such as government agencies and utility providers. It is SOC2 compliant and ensures that all recordings and generated code remain within your secure perimeter. This makes it the only viable "video-to-code" solution for critical infrastructure modernization where data privacy is non-negotiable.

How much time does Replay save compared to manual coding?#

On average, Replay provides a 70% time savings. While a manual rewrite of a single complex enterprise screen takes approximately 40 hours, Replay can generate the same documented React component in about 4 hours. For a standard enterprise project with 50-100 screens, this reduces the modernization timeline from 18-24 months down to just a few weeks.

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Ready to modernize without rewriting? Book a pilot with Replay