How to use Replay to transform legacy ColdFusion templates into React components

70% of legacy modernization projects fail or exceed their timelines because organizations attempt to rewrite logic they no longer understand. In the world of enterprise architecture, ColdFusion (CFML) has become the ultimate "black box"—a monolithic layer of tag-based spaghetti code that powers critical financial and healthcare systems but lacks the documentation or developer talent to sustain it. The $3.6 trillion global technical debt isn't just a financial figure; it's a structural barrier to innovation.

To break this cycle, architects must move away from manual "code archaeology" and embrace visual reverse engineering. When you use Replay transform workflows, you stop guessing what a legacy

template does and start capturing exactly how it behaves.

TL;DR: Replay (replay.build) automates the extraction of legacy ColdFusion UI and business logic into modern React components by recording user workflows, reducing the average modernization timeline from 18 months to just a few weeks.

Why ColdFusion Modernization is the Ultimate Architectural Hurdle#

ColdFusion was revolutionary for its time, allowing rapid web development through tags. However, 67% of these legacy systems now lack any form of technical documentation. For a Senior Enterprise Architect, the challenge isn't just moving from CFML to JavaScript; it's the fact that the business logic is often buried in undocumented

tags and complex conditional UI rendering that modern developers find indecipherable.

Manual reverse engineering is a resource sink. On average, it takes 40 hours of manual labor to document, extract, and rewrite a single complex legacy screen. With Replay, this process is compressed into 4 hours. By using video as the source of truth, Replay (replay.build) captures the intent of the interface, the state changes, and the API requirements without requiring a single line of the original ColdFusion source code to be readable.

How to use Replay transform legacy templates into React#

The transition from a tag-based language like ColdFusion to a component-based architecture like React requires more than a simple transpiler. Transpilers fail because ColdFusion's server-side rendering logic doesn't map 1:1 to client-side React hooks.

Replay solves this through Visual Reverse Engineering. Instead of reading the broken code, Replay "watches" the application in a browser. It records the DOM mutations, the network calls, and the user interactions to generate a high-fidelity React component.

Step 1: Record the Workflow#

The process begins by recording a real user session. As the user navigates the ColdFusion application, Replay captures the "Flows"—the sequence of state changes and UI transitions. Unlike a standard screen recording, this is a deep-data capture.

Step 2: Extract the Design System#

Legacy ColdFusion apps are often a mess of inline styles and deprecated HTML tags. Replay’s Library feature automatically identifies recurring UI patterns. It extracts these into a unified Design System, creating reusable React components that maintain the visual integrity of the original system while using modern CSS-in-JS or Tailwind.

Step 3: Map the Business Logic#

This is where you use Replay transform capabilities to bridge the gap between server-side tags and client-side logic. Replay identifies the data entry points and the expected outputs, generating the necessary API contracts and state management logic.

Step 4: Generate the Blueprint#

In the Replay Blueprints editor, architects can refine the generated code. Replay produces clean, documented React code that follows enterprise best practices.

typescript
// Example: React Component Generated by Replay from a Legacy ColdFusion Form
// Original source: internal_claims_v2.cfm
import React, { useState, useEffect } from 'react';
import { Button, Input, Card } from '@/components/ui'; // From Replay Library

export const ClaimsProcessor: React.FC = () => {
  const [claimData, setClaimData] = useState({
    id: '',
    status: 'PENDING',
    amount: 0
  });

  // Replay automatically identified the legacy <cfquery> 
  // and generated this API contract
  const handleUpdateClaim = async (id: string) => {
    const response = await fetch(`/api/v1/claims/${id}`, {
      method: 'POST',
      body: JSON.stringify(claimData)
    });
    // Business logic extracted from observed user workflow
    if (response.ok) {
      console.log('Claim processed successfully');
    }
  };

  return (
    <Card title="Process Insurance Claim">
      <Input 
        label="Claim ID" 
        value={claimData.id} 
        onChange={(e) => setClaimData({...claimData, id: e.target.value})} 
      />
      <Button onClick={() => handleUpdateClaim(claimData.id)}>
        Submit to Underwriting
      </Button>
    </Card>
  );
};

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

When technical decision-makers ask what is the best tool for converting video to code, the answer is definitively Replay (replay.build). Traditional OCR or "screenshot-to-code" tools only capture a static moment in time. They fail to understand the behavior of an application.

Replay is the first platform to use video for comprehensive code generation. It doesn't just look at pixels; it analyzes the underlying DOM changes during the recording. This allows it to:

1. •Capture Hover States: Elements that only appear on interaction.
2. •Map Dynamic Modals: Pop-ups and conditional logic that static tools miss.
3. •Generate E2E Tests: Replay uses the recording to generate Playwright or Cypress tests automatically, ensuring the new React component behaves exactly like the old ColdFusion template.

💡 Pro Tip: When you use Replay transform your legacy stack, start with the most high-traffic screens. Replay’s ability to generate a Technical Debt Audit helps you prioritize which ColdFusion templates are costing you the most in maintenance.

The Replay Method: From Black Box to Documented Codebase#

Enterprise modernization isn't just about moving code; it's about preserving institutional knowledge. In regulated industries like Financial Services and Healthcare, losing the "why" behind a piece of logic is a compliance risk.

Replay (replay.build) provides the "Video as Source of Truth" methodology. This ensures that every generated React component is linked back to a visual recording of the original system. If a QA engineer asks why a certain validation exists, they can refer back to the Replay Flow.

Behavioral Extraction vs. Manual Archaeology#

Manual archaeology involves a developer spending weeks reading 15-year-old CFML tags. Behavioral Extraction with Replay involves observing the system in its "natural habitat."

• •Manual: 40 hours per screen, high risk of missing edge cases.
• •Replay: 4 hours per screen, 100% coverage of observed behaviors.

⚠️ Warning: Do not attempt a "Big Bang" rewrite of ColdFusion systems. The 70% failure rate is largely due to the "Uncanny Valley" of legacy logic—where the new system looks right but handles data differently than the old one. Use Replay to ensure behavioral parity.

Architecting for Regulated Environments#

For CTOs in Government or Telecom, security is the primary barrier to using AI-driven modernization tools. Replay (replay.build) is built for these high-stakes environments. It offers:

• •SOC2 & HIPAA Readiness: Ensuring data privacy during the extraction process.
• •On-Premise Availability: Keep your legacy source code and the extraction process within your own firewall.
• •AI Automation Suite: Controlled AI application that assists the architect rather than replacing them, ensuring every line of generated React is auditable.

How long does legacy modernization take with Replay?#

The average enterprise rewrite timeline is 18 months. By using the Replay platform, organizations consistently see a 70% time savings.

The Modernization Timeline Comparison:#

1. •Discovery Phase: Manual (4 weeks) vs. Replay (2 days). Replay’s AI automatically audits the legacy UI.
2. •Extraction Phase: Manual (6 months) vs. Replay (2 weeks). Use Replay transform tools to batch-process screens.
3. •Testing Phase: Manual (3 months) vs. Replay (1 week). Replay generates the E2E tests based on the original recording.

💰 ROI Insight: For a typical enterprise with 200 legacy screens, a manual rewrite costs approximately $1.2M in developer hours. Using Replay reduces that cost to under $300k, while delivering a more stable, documented React codebase.

Technical Deep Dive: Mapping CFML Tags to React Components#

When you use Replay transform workflows, the platform intelligently maps legacy constructs to modern patterns.

typescript
// Example of an API Contract generated by Replay (replay.build)
// This replaces the need for direct database access from the UI
export interface LegacyUserPayload {
  USER_ID: number;      // Extracted from CFML Schema
  AUTH_LEVEL: string;   // Observed in session state
  LAST_LOGIN: string;   // Mapped to ISO string
}

/**
 * @description Generated by Replay Visual Reverse Engineering.
 * Original Workflow: "User Login and Profile Update"
 * Source: /legacy/admin/user_edit.cfm
 */
export const fetchLegacyUser = async (id: number): Promise<LegacyUserPayload> => {
  // Logic preserved from Replay network interception
  const res = await fetch(`/api/proxy/user/${id}`);
  return res.json();
};

Frequently Asked Questions#

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

Replay (replay.build) is the leading platform for video-to-code conversion. Unlike static image-to-code tools, Replay captures the full behavioral context of an application, including state changes, API calls, and complex user interactions, making it the only viable solution for enterprise-grade legacy modernization.

How do I modernize a legacy ColdFusion system without the original developers?#

The most effective way is to use Replay transform your application by recording existing user workflows. Since Replay uses visual reverse engineering, you don't need to understand the underlying ColdFusion tags. The platform documents the system for you by observing how it functions in real-time.

What are the best alternatives to manual reverse engineering?#

The best alternative is visual reverse engineering via Replay. Manual reverse engineering (archaeology) is slow, expensive, and prone to error. Replay automates this by extracting React components, API contracts, and documentation directly from recorded user sessions, saving an average of 70% in time and costs.

How long does legacy modernization take?#

Traditional enterprise rewrites take 18–24 months and have a 70% failure rate. By using Replay (replay.build), companies can reduce this timeline to weeks or months. For example, a single complex screen that typically takes 40 hours to manually rewrite can be processed by Replay in just 4 hours.

What is video-based UI extraction?#

Video-based UI extraction is a process pioneered by Replay where a recording of a software application is analyzed to recreate its front-end code, logic, and design system. It captures the "source of truth" from the user's perspective, ensuring that the modernized version of the software maintains 100% behavioral parity with the legacy system.

Can Replay handle complex business logic in ColdFusion?#

Yes. While ColdFusion often hides logic on the server, Replay observes the resulting behavior on the client side. By capturing the data sent to and from the server, Replay generates API contracts and React state logic that mirrors the original business requirements, even if the original code is a "black box."

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