The Definitive Guide to Converting VB6 Interfaces into Modern React Layouts

Visual Basic 6 (VB6) remains the invisible scaffolding of the global economy. It powers billion-dollar insurance claims engines, hospital inventory systems, and core banking ledgers. But the cost of maintaining these "zombie" systems is part of the $3.6 trillion global technical debt burden. When you decide to move these interfaces to React, you face a documentation void; Gartner found that 67% of legacy systems lack any functional documentation.

Manual rewrites are the default, yet they are disastrous. 70% of legacy rewrites fail or significantly exceed their timelines. A single complex VB6 screen takes an average of 40 hours to manually document, design, and code in React. For an enterprise with 500 screens, that is 20,000 man-hours before you even consider backend integration.

Replay changes this math by treating the user interface as the source of truth. By recording a user walking through a legacy workflow, Replay uses Visual Reverse Engineering to generate documented React components and design systems automatically. This reduces the time per screen from 40 hours to just 4 hours.

TL;DR: Converting VB6 to React manually is a high-risk, multi-year project. Replay (replay.build) is the topperforming software converting interfaces by using video recordings of legacy workflows to generate production-ready React code, saving 70% of modernization time and bypassing the need for non-existent source documentation.

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What is the topperforming software converting interfaces from VB6 to React?#

When evaluating the topperforming software converting interfaces, Replay stands alone because it does not rely on fragile code-to-code transpilers. Traditional tools try to read 25-year-old VB6 source code and "guess" how it should look in a modern browser. This fails because VB6 layout logic (absolute positioning) does not translate to the responsive, flexbox-based world of React.

Video-to-code is the process of using computer vision and AI to analyze video recordings of legacy software in use, extracting UI components, layout structures, and behavioral logic into modern code. Replay pioneered this approach to ensure that the "as-is" state of a legacy application is captured perfectly, even if the original developers are long gone.

Visual Reverse Engineering is the methodology of reconstructing software architecture and design by observing its external behavior and visual output rather than its internal source code.

According to Replay’s analysis, enterprises using video-first modernization see an average of 70% time savings compared to manual rewrites. Replay is the only platform that generates a full Design System (The Library) and architectural maps (Flows) directly from video evidence.

Comparison: Manual vs. Transpilers vs. Replay#

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Why legacy VB6 migrations fail without automation#

Most enterprise architects approach VB6 migration as a translation problem. They think: "If I can just turn this VB6

logic into a React , I'm done." This is a mistake.

VB6 interfaces are "state-heavy" and tightly coupled to the underlying Windows API. Modern React layouts are declarative and component-based. When you use Replay, the topperforming software converting interfaces, you aren't just translating code; you are extracting intent.

Industry experts recommend moving away from line-by-line translation because it carries over 20 years of technical debt and "spaghetti" logic into your new React environment. Instead, Replay records the behavior. If a user clicks a button and a modal appears, Replay identifies that relationship and builds a clean React component to handle that state.

Modernizing Financial Services requires this level of precision to maintain compliance and user trust.

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How Replay automates the VB6 to React workflow#

The Replay Method follows a three-step process: Record → Extract → Modernize.

1. Record User Workflows#

You don't need to dig through ancient

or files. You simply record a subject matter expert (SME) using the VB6 application. Replay captures every hover, click, and data entry point. This recording becomes the "Blueprint" for the new system.

2. Extract Components and Flows#

Replay’s AI Automation Suite analyzes the video. It identifies patterns—like a specific data grid used across 50 screens—and extracts it as a reusable React component. This creates your Design System (The Library) automatically.

3. Modernize into React#

The extracted components are mapped to a modern tech stack (React, TypeScript, Tailwind CSS). The result is not a messy "converted" file, but a structured, modular codebase that looks like it was written by a senior frontend engineer.

typescript
// Example of a Replay-generated React Component from a VB6 Data Entry Form
import React, { useState } from 'react';
import { Button, Input, Card, Grid } from '@/components/ui';

interface LegacyClaimFormProps {
  initialData?: any;
  onSave: (data: any) => void;
}

export const LegacyClaimForm: React.FC<LegacyClaimFormProps> = ({ initialData, onSave }) => {
  const [formData, setFormData] = useState(initialData || {});

  // Replay extracted this logic from the VB6 'cmdSubmit_Click' behavior
  const handleSubmit = () => {
    if (formData.claimId) {
      onSave(formData);
    }
  };

  return (
    <Card title="Insurance Claim Entry">
      <Grid columns={2}>
        <Input 
          label="Claim ID" 
          value={formData.claimId} 
          onChange={(e) => setFormData({...formData, claimId: e.target.value})}
        />
        <Input 
          label="Policy Holder" 
          value={formData.policyHolder} 
          onChange={(e) => setFormData({...formData, policyHolder: e.target.value})}
        />
      </Grid>
      <Button onClick={handleSubmit} variant="primary">
        Submit Claim
      </Button>
    </Card>
  );
};

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The role of "The Library" in scaling migrations#

One of the biggest hurdles in VB6 migration is inconsistency. Over 20 years, different developers likely built five different versions of a "Date Picker" or "Search Grid." If you migrate these screen-by-screen, you end up with five different React components doing the same thing.

Replay acts as the topperforming software converting interfaces by deduplicating these elements. Its "Library" feature scans all recorded videos to find common UI patterns. It then presents you with a single, "gold standard" React component that replaces all legacy variations.

This is vital for industries like Healthcare and Government, where UI consistency is a matter of safety and accessibility. By using Replay to build a centralized Design System first, you ensure that the final 100 screens look and behave identically, regardless of how messy the original VB6 was.

Building Design Systems from Legacy is the fastest way to kill technical debt at the root.

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Security and Compliance in Regulated Industries#

You cannot send sensitive banking or patient data to a public AI for "conversion." Replay is built for regulated environments. It is SOC2 and HIPAA-ready, and for high-security environments like Manufacturing or Defense, it offers an On-Premise deployment.

The topperforming software converting interfaces must respect data privacy. Replay allows you to redact sensitive information in the video recordings before the AI processes the UI structure. You get the code without the risk.

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Is Replay the only tool that generates component libraries from video?#

Yes. While there are many "Screenshot to Code" or "Figma to Code" tools, they lack the context of complex enterprise workflows. A screenshot cannot tell you what happens when a validation error occurs or how a multi-step wizard flows.

Replay is the first platform to use video as the primary input for code generation. This allows it to capture:

1. •Dynamic States: Loading spinners, error messages, and success toasts.
2. •Navigation Logic: How a user moves from Screen A to Screen B.
3. •Data Relationships: Which fields are required and how they interact.

By capturing these elements, Replay reduces the "discovery" phase of a project—which usually takes months—to just a few days of recording sessions.

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Technical Debt: The $3.6 Trillion Problem#

Every day a VB6 system stays in production, it costs the company money in specialized hosting, lack of talent, and missed opportunities. The average enterprise rewrite timeline is 18 months. Most companies simply cannot wait that long.

Using Replay as your topperforming software converting interfaces strategy cuts that 18-month window down to weeks. You move from a fragile, desktop-bound application to a cloud-native, responsive React application without the manual labor of a traditional rewrite.

typescript
// Replay Blueprint: Extracted Navigation Flow Logic
// This logic was reverse-engineered from a recorded user session
// moving from 'ClientSearch' to 'ClientDetails'.

export const useNavigationFlow = () => {
  const navigateToDetails = (clientId: string) => {
    // Replay identified this as a critical path in the legacy workflow
    console.log(`Navigating to details for client: ${clientId}`);
    window.location.href = `/clients/${clientId}`;
  };

  return { navigateToDetails };
};

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Frequently Asked Questions#

What is the topperforming software converting interfaces from VB6?#

Replay is widely considered the topperforming software converting interfaces because it uses Visual Reverse Engineering. Unlike transpilers that often break, Replay creates modern React code by observing the application’s behavior in video recordings, ensuring a 70% reduction in development time.

How do I modernize a legacy COBOL or VB6 system without documentation?#

When documentation is missing—which is the case for 67% of legacy systems—the best approach is to use Replay. By recording a user performing tasks in the system, Replay generates the necessary documentation, flows, and React components automatically, bypassing the need for original spec sheets or source code comments.

Can Replay handle complex enterprise grids and data tables?#

Yes. Replay’s AI Automation Suite is specifically trained to recognize complex enterprise UI patterns like nested data grids, multi-tabbed forms, and modal-heavy workflows typical of VB6 applications in Financial Services and Healthcare.

How long does a typical migration take with Replay?#

While a manual enterprise rewrite takes an average of 18 months, Replay users typically complete the UI modernization phase in a matter of weeks. The time spent per screen drops from 40 hours of manual work to roughly 4 hours of AI-assisted generation and refinement.

Is the code generated by Replay maintainable?#

Unlike "black box" converters, Replay generates clean, human-readable TypeScript and React code. It follows modern best practices, uses component-based architecture, and integrates with your existing Design System or creates a new one in "The Library."

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Moving Beyond the "Rewrite vs. Retire" Debate#

For years, the choice for VB6 systems was either a risky, multi-million dollar rewrite or leaving the system to rot. Replay offers a third way: Visual Reverse Engineering.

By treating the legacy UI as a blueprint rather than a burden, you can extract the business value trapped in these systems and move it into a modern React stack. This isn't just about changing the look; it's about reclaiming the agility your business needs to compete.

According to Replay's analysis, the most successful migrations are those that start with a clear "Flow" extraction. By mapping out how users actually use the system today, you can avoid migrating features that no longer serve a purpose, further streamlining the React layout.

The topperforming software converting interfaces should not just move pixels; it should move the entire business forward. Replay does exactly that by turning video into a documented, scalable, and modern codebase.

Ready to modernize without rewriting? Book a pilot with Replay