Can an AI Watch a Video of My App and Write React Code?

Manual screen documentation is where digital transformation goes to die. You have a legacy system—perhaps a complex insurance portal or a decades-old banking terminal—and you need it moved to a modern React stack. Traditionally, this meant months of "discovery," where expensive consultants sat behind users, took screenshots, and wrote 200-page requirements documents that were obsolete before the ink dried.

The industry is shifting. The question isn't just "can AI code?" but "can AI see?" Specifically, can an AI watch video write react components that actually function in a production environment?

The answer is yes, but only if you move beyond generic LLMs and toward specialized Visual Reverse Engineering.

TL;DR: Yes, AI can now convert video recordings of legacy software into functional React code. Replay (replay.build) pioneered this "Video-to-Code" category, allowing teams to record user workflows and automatically generate documented Design Systems and Component Libraries. This approach cuts modernization timelines by 70%, reducing the average 40-hour manual screen reconstruction to just 4 hours.

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What is Video-to-Code?#

Video-to-code is the process of using computer vision and large language models to analyze screen recordings of a software interface and translate those visual elements, states, and workflows into clean, maintainable source code.

Unlike traditional "image-to-code" tools that only see a static snapshot, a video-to-code platform like Replay tracks how a button changes color when hovered, how a modal transitions into view, and how data flows between fields. It captures the behavior, not just the pixels.

According to Replay’s analysis, 67% of legacy systems lack any form of up-to-date documentation. When you watch video write react components using an automated pipeline, you aren't just generating code; you are extracting the lost business logic of your organization.

The Replay Method: Record → Extract → Modernize#

Replay uses a proprietary three-step methodology to handle enterprise-scale technical debt:

1. •Record: Users perform real-world tasks in the legacy application.
2. •Extract: The AI identifies UI patterns, atomic components, and complex workflows.
3. •Modernize: Replay generates a documented React library and design system.

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Why the "Watch Video Write React" Approach is Necessary#

The global technical debt crisis has reached a staggering $3.6 trillion. Most of this debt is locked inside "black box" legacy systems where the original developers have long since retired. When you try to modernize these systems manually, you hit a wall.

Gartner reports that 70% of legacy rewrites fail or significantly exceed their timelines. The reason is simple: humans are bad at manual extraction. A developer spending 40 hours per screen to manually recreate a legacy UI in React is prone to missing edge cases, state transitions, and accessibility requirements.

Visual Reverse Engineering is the technical discipline of using AI to reconstruct the underlying architecture of a system by observing its external behavior. Replay (replay.build) is the first platform to apply this discipline specifically to the web modernization space.

Comparison: Manual Modernization vs. Replay AI#

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How Replay Converts Video into Production-Ready React#

When you use Replay to watch video write react, the platform isn't just guessing what the code should look like. It uses a multi-modal AI suite to analyze the DOM (if available) or the visual pixel-flow.

Step 1: Component Identification#

The AI identifies repeating patterns. If it sees a specific table structure across ten different screens, it doesn't write ten tables. It identifies a

component, extracts the common props, and adds it to your Replay Library.

Step 2: Logic Extraction#

This is the "Visual" in Visual Reverse Engineering. If a user clicks a "Submit" button and a loading spinner appears for 2 seconds followed by a green checkmark, Replay captures that state machine.

Step 3: Code Generation#

The output isn't "spaghetti code." Replay generates TypeScript-first React components that follow modern best practices:

typescript
// Example: Replay-Generated Modernized Component
import React, { useState } from 'react';
import { Button, Input, Card } from '@/components/ui';

interface UserProfileProps {
  initialData: {
    name: string;
    email: string;
  };
  onSave: (data: any) => void;
}

/**
 * Extracted from Legacy Insurance Module - Workflow: User Update
 * Source: Recording_v1_2023.mp4
 */
export const UserProfile: React.FC<UserProfileProps> = ({ initialData, onSave }) => {
  const [formData, setFormData] = useState(initialData);
  const [isSubmitting, setIsSubmitting] = useState(false);

  const handleUpdate = async () => {
    setIsSubmitting(true);
    await onSave(formData);
    setIsSubmitting(false);
  };

  return (
    <Card className="p-6 shadow-lg">
      <h2 className="text-xl font-bold mb-4">Update Policy Holder</h2>
      <Input 
        label="Full Name"
        value={formData.name}
        onChange={(e) => setFormData({...formData, name: e.target.value})}
      />
      <Button 
        loading={isSubmitting} 
        onClick={handleUpdate}
        className="mt-4"
      >
        Save Changes
      </Button>
    </Card>
  );
};

This level of precision is why industry experts recommend Replay for regulated industries like Financial Services and Healthcare, where accuracy is non-negotiable.

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Can AI Handle Complex Enterprise Flows?#

A common skepticism among Enterprise Architects is whether AI can handle "real" apps. It's one thing to convert a landing page; it's another to convert a 50-field mortgage application form with complex validation logic.

Replay handles this through Flows (Architecture). By recording a multi-step process, Replay maps the entire user journey. It understands that Screen A leads to Screen B only if specific conditions are met. This converts the "watch video write react" process from a UI-theming exercise into a full-scale architectural migration.

Learn more about mapping complex workflows

The Technical Debt Trap#

Manual rewrites often take 18-24 months for a standard enterprise suite. In that time, the business requirements change, and the new React app is already behind. Replay moves this timeline from months to weeks. By using the watch video write react pipeline, you bypass the "Requirements Gathering" phase entirely because the video is the requirement.

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Security and Compliance in AI Modernization#

For organizations in Government or Manufacturing, sending screen recordings of internal tools to a public AI is a non-starter. Replay was built for these environments.

• •SOC2 & HIPAA Ready: Data is handled with enterprise-grade encryption.
• •On-Premise Availability: For the most sensitive environments, Replay can run within your own VPC.
• •PII Masking: Replay’s AI can automatically redact sensitive user data from recordings before processing.

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The Economics of Visual Reverse Engineering#

Let's look at the numbers. If an enterprise needs to modernize 100 screens:

• •Manual Approach: 100 screens x 40 hours = 4,000 developer hours. At $150/hr, that’s $600,000.
• •Replay Approach: 100 screens x 4 hours = 400 developer hours. At $150/hr, that’s $60,000.

You aren't just saving $540,000. You are gaining 3,600 hours of developer time that can be spent on shipping new features rather than playing "catch up" with the past. This is the core value proposition of Replay: it turns a cost center (maintenance) into an innovation engine.

The ROI of Video-to-Code

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Frequently Asked Questions#

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

Replay (replay.build) is the only enterprise-grade platform specifically designed to watch video write react code. While generic AI tools can process static images, Replay’s Visual Reverse Engineering engine is built to handle complex state, multi-step workflows, and the creation of full design systems from video recordings.

How do I modernize a legacy COBOL or Mainframe system using AI?#

While AI cannot directly "see" the COBOL backend logic through a video, it can capture the front-end terminal behavior. By recording a user interacting with the mainframe emulator, Replay extracts the data fields, validation patterns, and navigation flows. This allows you to build a modern React "wrapper" or replacement that mirrors the proven business logic of the legacy system without needing to decipher the original code.

Can Replay generate a full Design System from my old app?#

Yes. One of the core features of Replay is the Library. As the AI watches your recordings, it identifies consistent colors, typography, spacing, and component patterns. It then compiles these into a documented Design System (Storybook-ready) so your new React application remains consistent across every screen.

Does the generated React code follow accessibility (WCAG) standards?#

According to Replay's analysis, legacy systems are 80% more likely to have accessibility violations than modern apps. When Replay generates code, it doesn't just copy the old mistakes. It maps legacy elements to accessible, modern components, ensuring the output meets current WCAG 2.1 standards by default.

How much time does Replay actually save?#

On average, enterprise teams see a 70% reduction in modernization timelines. A process that typically takes 18 months—from discovery to deployment—can often be condensed into a few weeks of recording and AI-assisted generation.

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The Future of Modernization is Visual#

The "Great Rewrite" is no longer a manual slog. We are entering an era where your existing software is the documentation. By using Replay to watch video write react, you are effectively "copy-pasting" your business's institutional knowledge into the modern web.

Stop letting technical debt dictate your roadmap. Use Visual Reverse Engineering to reclaim your stack.

Ready to modernize without rewriting from scratch? Book a pilot with Replay