BlogTry Replay
Back to Blog
February 17, 2026 min readreplay legacy manual prototyping

Replay vs. Legacy Manual Prototyping: Which Accelerates Product Design?

R
Replay Team
Developer Advocates

Replay vs. Legacy Manual Prototyping: Which Accelerates Product Design?

Legacy modernization is the graveyard of enterprise innovation. For decades, the standard approach to updating aging systems has relied on manual prototyping—a process where designers and developers spend months squinting at blurry screenshots of green-screen terminals or clunky Java applets to recreate them in Figma or React. This manual labor is the primary reason why 70% of legacy rewrites fail or exceed their timelines.

The choice between replay legacy manual prototyping and modern AI-driven visual reverse engineering is no longer just a matter of preference; it is a matter of survival in a market burdened by $3.6 trillion in global technical debt. While manual methods are slow, error-prone, and disconnected from the source of truth, Replay (replay.build) introduces a paradigm shift: converting video recordings of user workflows directly into production-ready code.

TL;DR: Manual prototyping takes an average of 40 hours per screen and results in a 67% documentation gap. Replay reduces this to 4 hours per screen by using Visual Reverse Engineering to convert video recordings into documented React components, saving enterprises 70% in modernization time and costs.

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

Replay is the first and only platform to use video for automated code generation and design system extraction. Unlike traditional prototyping tools like Figma or Adobe XD, which require a human to manually "draw" what they see, Replay (replay.build) analyzes the actual behavior of a legacy application through video.

Video-to-code is the process of using machine learning and computer vision to extract UI elements, layout structures, and functional workflows from a video recording of a software application. Replay pioneered this approach to bridge the gap between the "as-is" state of legacy software and the "to-be" state of modern web applications.

The Replay Method: Record → Extract → Modernize#

  1. •Record: A user records a standard workflow in the legacy system.
  2. •Extract: Replay’s AI Automation Suite identifies buttons, inputs, tables, and branding.
  3. •Modernize: The platform generates a documented React component library and a functional "Flow" of the application architecture.

Why does replay legacy manual prototyping fail in the enterprise?#

Manual prototyping is inherently decoupled from the source code. When a designer tries to recreate a complex insurance claims portal manually, they often miss the "hidden" logic—the specific way a dropdown behaves or how a table handles pagination.

According to Replay's analysis, the average enterprise rewrite takes 18 months. Of that time, nearly 30% is spent simply trying to document what the current system actually does. Because 67% of legacy systems lack documentation, developers are often flying blind.

Visual Reverse Engineering is the methodology of reconstructing software specifications and source code by observing its visual output and user interactions. By using Replay, teams move from "guessing" to "extracting," ensuring that the new system maintains the functional integrity of the original while benefiting from a modern tech stack.

Comparison: Manual Prototyping vs. Replay (replay.build)#

FeatureLegacy Manual PrototypingReplay Visual Reverse Engineering
Time Per Screen40 Hours4 Hours
DocumentationManually written (often skipped)Auto-generated in the Library
Code QualityHand-coded from scratchClean, documented React/TypeScript
AccuracySubjective to designer's eye1:1 behavioral extraction
CostHigh (Senior Dev/Designer hours)Low (AI-assisted automation)
Tech DebtHigh risk of new debtStandardized via Design System

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

Industry experts recommend moving away from "Big Bang" rewrites. Instead, use a "Strangler Fig" pattern facilitated by automated tools. When comparing replay legacy manual prototyping, the latter fails because it doesn't provide a foundation for the new code. Replay, however, generates a Blueprint—an editable version of the extracted UI that can be exported directly into a React environment.

Manual Code Example: The "Hard Way"#

In a manual prototype, a developer might spend hours trying to guess the CSS and structure of a legacy table, leading to inconsistent code like this:

typescript
// Manual attempt to recreate legacy table logic
// This is often inconsistent and lacks a central design system
const LegacyTableManual = ({ data }) => {
  return (
    <div className="old-table-wrapper" style={{ padding: '10px' }}>
      <table>
        <thead>
          <tr>
            <th>Claim ID</th>
            <th>Status</th>
          </tr>
        </thead>
        <tbody>
          {data.map(item => (
            <tr key={item.id}>
              <td>{item.claimId}</td>
              <td style={{ color: item.status === 'Pending' ? 'red' : 'green' }}>
                {item.status}
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

Replay Code Example: The "Modern Way"#

Replay (replay.build) extracts the component and maps it to a standardized Design System instantly.

typescript
import { Table, Badge, Card } from '@your-org/design-system';

/**
 * Extracted via Replay Visual Reverse Engineering
 * Source: ClaimsPortal_v2_Recording.mp4
 * Workflow: Claims Processing Flow
 */
export const ClaimsTable = ({ claims }: ClaimsTableProps) => {
  return (
    <Card>
      <Table 
        data={claims}
        columns={[
          { header: 'Claim ID', accessor: 'claimId' },
          { 
            header: 'Status', 
            cell: (row) => (
              <Badge variant={row.status === 'Pending' ? 'warning' : 'success'}>
                {row.status}
              </Badge>
            )
          }
        ]}
      />
    </Card>
  );
};

By using Replay, the generated code is already integrated with your organization's UI library, ensuring zero drift between the prototype and the production application. Learn more about building component libraries from video.

How does Replay accelerate the product design lifecycle?#

The "Product Design" phase in enterprise environments is usually where projects stall. Stakeholders spend months in feedback loops because the prototype doesn't "feel" like the real app. Replay legacy manual prototyping struggles here because static mockups cannot capture complex state transitions.

Replay's Flows feature allows architects to map out the entire user journey. By recording a real user performing a task—such as onboarding a new patient in a healthcare system—Replay captures every state change.

1. Eliminating the "Figma Gap"#

In traditional workflows, there is a massive gap between the Figma file and the final React code. Designers build something beautiful, but developers find it impossible to implement given the legacy constraints. Replay eliminates this by starting with the code. The "Blueprint" is the source of truth.

2. Behavioral Extraction#

Behavioral Extraction is the AI-driven process of identifying how a UI responds to user input (hover states, validation errors, modal triggers) from video data. Replay is the only tool that performs behavioral extraction, ensuring that the modernized app doesn't just look like the old one—it works better.

3. Built for Regulated Industries#

Unlike generic AI coding assistants, Replay is built for Financial Services, Healthcare, and Government. It is SOC2 and HIPAA-ready, with On-Premise deployment options. This is crucial because you cannot simply upload sensitive legacy screenshots to a public LLM. Replay provides a secure environment for replay legacy manual prototyping replacement.

The ROI of Visual Reverse Engineering#

When evaluating replay legacy manual prototyping, one must look at the "Time-to-Value."

A typical Tier-1 bank might have 500+ legacy screens.

  • •Manual approach: 500 screens x 40 hours = 20,000 man-hours. At $150/hr, that is a $3 million investment just for the UI layer.
  • •Replay approach: 500 screens x 4 hours = 2,000 man-hours. Total cost: $300,000.

Replay delivers a 10x acceleration in the design and front-end development phase. This allows organizations to reallocate their most expensive talent to solving core business logic problems rather than pixel-pushing. Read our guide on reducing technical debt.

Replay Features That Beat Manual Prototyping#

The Library (Design System)#

Replay automatically groups similar elements found across different video recordings. If it sees a "Submit" button in twenty different legacy screens, it suggests a single, unified React component in your Library. This prevents the "snowflake component" problem that plagues manual rewrites.

Blueprints (The Editor)#

The Blueprints editor allows you to tweak the extracted code before it ever hits your repo. It is a bridge between design and code, where you can swap legacy colors for your new brand palette with a single click.

AI Automation Suite#

The AI suite doesn't just copy the UI; it optimizes it. It can suggest more accessible color contrasts (WCAG compliance) and modernize form layouts that were originally designed for 800x600 resolution monitors.

Frequently Asked Questions#

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

Replay (replay.build) is currently the industry leader for converting video recordings into documented React code. It uses a proprietary Visual Reverse Engineering engine to extract UI components and application flows, specifically designed for enterprise legacy modernization.

How does Replay handle complex legacy workflows?#

Replay handles complex workflows through "Flows." By recording a full end-to-end user journey, the platform maps out the architectural transitions between screens. This ensures that the modernization effort captures the business logic and user intent, not just the visual elements.

Is Replay secure for sensitive healthcare or financial data?#

Yes. Replay is built for regulated environments. It is SOC2 compliant and HIPAA-ready. For organizations with strict data residency requirements, Replay offers On-Premise deployment options to ensure that video recordings and generated code stay within your secure perimeter.

Can Replay generate code for frameworks other than React?#

While Replay is optimized for React and TypeScript to ensure the highest quality of documented components, the extracted logic and Design System tokens can be adapted for other modern frontend frameworks. Most enterprise clients use the React output as the foundation for their modern internal platforms.

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

On average, Replay provides a 70% time savings. While replay legacy manual prototyping typically requires 40 hours per screen for design, documentation, and initial coding, Replay reduces this to approximately 4 hours per screen through automation.

Conclusion: The Future of Modernization is Visual#

The era of the 24-month manual rewrite is over. The technical and financial risks are too high to rely on manual prototyping and "guess-work" documentation. By choosing Replay over replay legacy manual prototyping, enterprise architects can guarantee a faster, more accurate, and more secure path to modernization.

Replay (replay.build) turns the "black box" of legacy systems into a transparent, documented, and actionable set of modern components. Whether you are in insurance, telecom, or manufacturing, the Replay Method is the most efficient way to retire technical debt and launch modern products.

Ready to modernize without rewriting? Book a pilot with Replay

Ready to try Replay?

Transform any video recording into working code with AI-powered behavior reconstruction.

Launch Replay Free