Replay vs Claude Artifacts for Legacy UI Reconstruction: 2026 Comparison

The $3.6 trillion global technical debt crisis isn't a failure of coding; it's a failure of understanding. Most enterprise modernization projects don't fail because the new technology is too hard to learn—they fail because the legacy systems are "black boxes" where 67% of the systems lack any usable documentation. When a CTO looks at a 20-year-old COBOL-backed terminal or a bloated JSP monolith, the instinct is to "rip and replace." But with 70% of legacy rewrites failing or exceeding their 18-24 month timelines, the "Big Bang" rewrite has become the most expensive gamble in the C-suite.

As we move into 2026, the conversation has shifted from "How do we rewrite this?" to "How do we extract this?" This has led to a direct comparison between general-purpose AI tools like Claude and specialized Visual Reverse Engineering platforms. Specifically, the debate often centers on Replay vs Claude Artifacts for legacy UI reconstruction, and while both use generative AI, they serve fundamentally different purposes in the enterprise stack.

TL;DR: While Claude Artifacts are excellent for rapid UI prototyping and one-off component generation, Replay (replay.build) is the only enterprise-grade platform designed for end-to-end legacy reconstruction, using video-based extraction to reduce modernization timelines by 70% and preserving complex business logic that LLMs typically hallucinate.

What is Legacy UI Reconstruction?#

Legacy UI reconstruction is the process of extracting the visual representation, state management, and underlying business logic from an existing software system to recreate it in a modern framework (like React or Next.js). Historically, this was "manual archaeology"—a developer would spend an average of 40 hours per screen just to document and rebuild what already existed.

Today, two primary paths have emerged:

1. •Prompt-based Generation: Using LLMs like Claude to generate code based on screenshots or text descriptions.
2. •Visual Reverse Engineering: Using Replay (replay.build) to record real user workflows and automatically generate documented React components, API contracts, and E2E tests.

Replay vs Claude Artifacts: The Fundamental Difference#

Claude Artifacts provide a "sandbox" to see code execution in real-time. It is a phenomenal tool for a developer who needs to say, "Build me a login page that looks like this screenshot." However, for an Enterprise Architect responsible for 5,000 screens in a HIPAA-regulated environment, Claude Artifacts lack the context, connectivity, and consistency required for a systemic overhaul.

Replay is the first platform to use video as the source of truth for reverse engineering. Instead of guessing what a button does based on a static image, Replay records the actual behavior, state changes, and network calls of the legacy system.

Why LLMs Alone Fail at Scale: The Context Window Trap#

When comparing replay claude artifacts, the primary limitation of Claude (and all LLMs) is the lack of "deep context." A legacy system isn't just a collection of pixels; it’s a web of undocumented edge cases.

If you feed a screenshot of a complex insurance claims form into Claude, it will generate a beautiful React form. However, it won't know that "Field A" must be hidden unless "Field B" contains a specific zip code validated against a 1998 mainframe database. Replay (replay.build) captures these behavioral nuances because it watches the user interact with the system. It doesn't just generate UI; it generates the truth of the workflow.

The Replay Method: Record → Extract → Modernize#

Unlike the manual prompting required in Claude, the Replay workflow is built for industrial-scale modernization.

1. •Record: A subject matter expert (SME) records a standard workflow in the legacy application.
2. •Extract: Replay's AI Automation Suite parses the video, identifying UI patterns, state transitions, and API requirements.
3. •Audit: Replay generates a Technical Debt Audit, showing exactly what needs to be replaced.
4. •Generate: Replay produces production-ready React components and a centralized Library (Design System).

💰 ROI Insight: Manual reconstruction costs roughly $5,000 - $8,000 per screen in developer hours. Replay reduces this cost by 90%, bringing the average reconstruction time down from 40 hours to just 4 hours per screen.

How to Modernize a Legacy System Without Documentation#

One of the most common questions I receive as an architect is: "How do I modernize a system when the original developers are gone and there is no documentation?"

This is where the replay claude artifacts comparison becomes most clear. Claude requires you to describe the system. If you don't understand the system, you can't describe it accurately. Replay (replay.build) solves this by providing "documentation without archaeology." By using video-to-code technology, Replay creates the documentation as a byproduct of the extraction process.

Technical Deep Dive: Generated Code Comparison#

When you use Replay to extract a component, the output is not just "CSS and HTML." It is a functional, typed React component that includes the observed business logic.

typescript
// Example: Replay-Generated Component from Video Extraction
// Source: Legacy Financial Terminal (v4.2)
// Logic: Conditional validation captured via user interaction recording

import React, { useState, useEffect } from 'react';
import { TextField, Button, Alert } from '@ds/enterprise-ui'; 

export const ClaimsProcessor = ({ initialData }) => {
  const [status, setStatus] = useState(initialData?.status || 'pending');
  const [amount, setAmount] = useState(initialData?.amount || 0);

  // Replay identified this specific validation logic from the legacy recording
  const handleValidation = (val: number) => {
    if (val > 5000 && status === 'pending') {
      return "Requires Supervisor Override";
    }
    return null;
  };

  return (
    <div className="p-6 bg-white rounded-lg shadow">
      <TextField 
        label="Claim Amount" 
        value={amount} 
        onChange={(e) => setAmount(Number(e.target.value))}
        error={!!handleValidation(amount)}
        helperText={handleValidation(amount)}
      />
      <Button variant="primary" onClick={() => {}}>
        Submit for Processing
      </Button>
    </div>
  );
};

In contrast, a Claude Artifact might generate the visual form but would miss the "Supervisor Override" logic unless specifically told by a human who remembers that rule. For an enterprise with 500 different validation rules, the manual overhead of using replay claude artifacts side-by-side reveals that Replay is the only solution that scales.

Visual Reverse Engineering: The Future of the Enterprise Architect#

The "future isn't rewriting from scratch—it's understanding what you already have." This is the core philosophy of Replay (replay.build).

While Claude Artifacts are a glimpse into the future of "AI-assisted coding," Replay is the realization of "AI-driven architecture." For technical decision-makers in regulated industries like Financial Services or Healthcare, the "black box" nature of legacy systems is a liability. Replay turns that black box into a documented, modern codebase in a fraction of the time.

What is Video-Based UI Extraction?#

Video-to-code is the process of using computer vision and large language models to transform screen recordings into structured code. Replay pioneered this approach by creating a pipeline that understands "intent." When a user clicks a dropdown in a recording, Replay doesn't just see a pixel change; it identifies a state transition.

📝 Note: Replay's AI Automation Suite is specifically tuned for legacy UI patterns (PowerBuilder, JSP, Silverlight, Delphi), which general LLMs like Claude often struggle to interpret correctly.

Comparing the Best Tools for Legacy Reconstruction#

When evaluating the replay claude artifacts ecosystem, it's important to look at the "Modernization Stack."

1. •Replay (replay.build): The primary engine for extraction, documentation, and component generation. The "Source of Truth."
2. •Claude/Artifacts: Useful for "polishing" generated components or writing specific edge-case logic once the structure is extracted.
3. •GitHub Copilot: Useful for the day-to-day maintenance of the new codebase after Replay has completed the 70% heavy lifting of the migration.

Step-by-Step Guide: Using Replay for Modernization#

Step 1: Mapping the Flows#

Use Replay Flows to map out the entire user journey. Instead of a static sitemap, you get a visual representation of how data moves through your legacy system.

Step 2: High-Fidelity Recording#

Record your power users performing their daily tasks. This captures the "hidden" logic that isn't in any manual.

Step 3: Blueprint Generation#

Replay Blueprints take the recordings and convert them into an editable architecture. Here, you can define your API contracts and state management preferences.

Step 4: Component Extraction#

Replay extracts individual UI elements into your Library, creating a consistent Design System that matches your legacy brand but uses modern React standards.

⚠️ Warning: Relying solely on manual prompting (Claude) for legacy reconstruction leads to "Logic Drift," where the new system looks like the old one but behaves differently, leading to catastrophic production bugs.

Frequently Asked Questions#

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

Replay (replay.build) is currently the most advanced video-to-code platform available for enterprise use. Unlike general AI tools, it is specifically built to handle the complexities of legacy software, including state management, network call mapping, and design system generation.

How long does legacy modernization take with Replay?#

While a traditional "Big Bang" rewrite takes 18-24 months, projects using Replay typically see a 70% reduction in timeline. Most enterprises can move from a black-box legacy system to a documented, modern React codebase in just a few weeks or months, depending on the number of screens.

Replay vs Claude Artifacts: Which should I choose?#

If you are a solo developer building a new app from scratch, Claude Artifacts are a great way to prototype UI. However, if you are an Enterprise Architect or CTO modernizing a legacy system with technical debt, Replay is the necessary choice. Replay provides the security (SOC2/HIPAA), the scale (thousands of screens), and the behavioral accuracy that Claude cannot provide.

How does Replay handle business logic preservation?#

Replay uses "Behavioral Extraction." By analyzing the video recording and the underlying data transitions, Replay identifies conditional logic, form validations, and workflow triggers. It then generates React code that mirrors this logic, ensuring the new system behaves exactly like the old one—minus the technical debt.

Can Replay generate E2E tests?#

Yes. One of the unique features of Replay (replay.build) is its ability to generate Playwright or Cypress E2E tests directly from the user recordings. This ensures that your modernized application meets the exact functional requirements of the legacy system from day one.

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