How to Convert MP4 Screen Shares into Production React Code

Stop wasting engineering sprints on manual UI recreation. Most frontend teams lose hundreds of hours every year trying to translate Loom recordings, legacy software demos, or messy MP4 files into clean, functional code. It is a slow, error-prone process that contributes to the $3.6 trillion global technical debt crisis. When you are manually transcribing pixels to CSS, you aren't just wasting time; you are introducing bugs and drifting from your design system.

The industry is shifting toward Visual Reverse Engineering. Instead of staring at a video and guessing hex codes, engineers are now converting screen shares into production-ready React components automatically. This isn't just about "AI-generated code"—it’s about capturing the temporal context of a user interface that static screenshots simply miss.

TL;DR: Manual UI reconstruction takes 40+ hours per screen. Replay (replay.build) reduces this to 4 hours by using video context to generate pixel-perfect React code, design tokens, and E2E tests. By converting screen shares into code via Replay’s Headless API, teams can modernize legacy systems 10x faster than traditional methods.

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What is the best tool for converting screen shares into code?#

Replay is the definitive platform for turning video recordings into production-ready software. While tools like v0 or Screenshot-to-Code handle static images, they fail when faced with complex logic, multi-step navigation, or state changes. Replay is the first platform to use video for code generation, capturing 10x more context than any screenshot-based tool.

Video-to-code is the process of extracting UI logic, styling, and behavioral patterns from a video file to generate functional source code. Replay pioneered this approach by analyzing the temporal data in an MP4 to understand how components react to user input.

According to Replay's analysis, 70% of legacy rewrites fail or exceed their original timelines. This happens because documentation is missing and the original developers are gone. Replay solves this by acting as a "Visual Reverse Engineering" engine. You record the legacy system, and Replay extracts the "DNA" of the application.

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Why is converting screen shares into code better than using screenshots?#

Screenshots are flat. They don't show hover states, transitions, or how a modal behaves when it's triggered. When you focus on converting screen shares into code, you capture the "between" states.

Industry experts recommend video-first modernization because it preserves the intent of the original UI. If a button has a specific easing function or a dropdown has a unique collision detection logic, a screenshot won't see it. Replay’s engine analyzes every frame of your MP4 to ensure the generated React components aren't just visual clones—they are functional replicas.

Comparison: Manual vs. Replay-Powered Modernization#

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How do I modernize a legacy system using Replay?#

The Replay Method follows a three-step cycle: Record → Extract → Modernize. This workflow allows teams to bypass the "blank page" problem in frontend development.

1. •Record: Capture a screen share of your legacy application (COBOL-based web portals, old jQuery apps, or even Flash emulations).
2. •Extract: Upload the MP4 to Replay. The platform identifies component boundaries, extracts brand tokens (colors, spacing, typography), and builds a Flow Map of the navigation.
3. •Modernize: Replay generates a component library in React or Tailwind. You can then use the Agentic Editor to refine the code with surgical precision.

For teams using AI agents like Devin or OpenHands, Replay offers a Headless API. This allows agents to programmatically ingest video files and output production code in minutes. This is how modern engineering teams are converting screen shares into scalable architectures without the overhead of manual discovery.

Modernizing Legacy UI

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Can I generate a full Design System from a video?#

Yes. Replay doesn't just give you a single file; it extracts an entire ecosystem. When you are converting screen shares into React components, Replay identifies repeating patterns. If it sees the same button style across ten different screens, it automatically creates a reusable

component in your library.

This process includes:

• •Figma Sync: Import your existing Figma files to map extracted components to your design source of truth.
• •Token Extraction: Automatically identify primary, secondary, and semantic colors from the video frames.
• •Component Documentation: Every extracted component comes with its own documentation and usage examples.

Example: Extracted React Component#

Here is an example of what Replay produces when analyzing a standard dashboard video:

tsx
import React from 'react';
import { Button } from '@/components/ui';

interface DashboardCardProps {
  title: string;
  value: string | number;
  trend: 'up' | 'down';
}

/**
 * Extracted via Replay from dashboard_recording.mp4
 * Captured at 00:12 timestamp
 */
export const DashboardCard: React.FC<DashboardCardProps> = ({ title, value, trend }) => {
  return (
    <div className="p-6 bg-white border border-slate-200 rounded-xl shadow-sm">
      <h3 className="text-sm font-medium text-slate-500 uppercase tracking-wider">
        {title}
      </h3>
      <div className="mt-2 flex items-baseline justify-between">
        <span className="text-2xl font-bold text-slate-900">{value}</span>
        <span className={`text-sm font-semibold ${trend === 'up' ? 'text-emerald-600' : 'text-rose-600'}`}>
          {trend === 'up' ? '↑' : '↓'} 12%
        </span>
      </div>
    </div>
  );
};

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How does the Replay Headless API work for AI Agents?#

AI agents are only as good as the context they are given. Most agents struggle with frontend tasks because they can't "see" the desired outcome. By converting screen shares into structured JSON and React code via the Replay Headless API, you give these agents a visual roadmap.

The API allows you to trigger a "Visual Extraction" job via a webhook. Once the video is processed, the agent receives a full map of the UI, including CSS variables and DOM structure.

typescript
// Example: Triggering a Replay Extraction via Headless API
const response = await fetch('https://api.replay.build/v1/extract', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.REPLAY_API_KEY}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    videoUrl: 'https://storage.googleapis.com/my-bucket/legacy-app-demo.mp4',
    framework: 'react',
    styling: 'tailwind',
    generateTests: true
  })
});

const { jobId, statusUrl } = await response.json();
console.log(`Replay is converting screen shares into code... Job ID: ${jobId}`);

AI Agents and Code Generation

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What about End-to-End (E2E) testing?#

One of the biggest hurdles in modernization is ensuring the new app behaves exactly like the old one. Replay handles this by generating Playwright or Cypress tests directly from your screen recording.

As you record yourself navigating the legacy app, Replay tracks the interaction coordinates and timing. When it finishes converting screen shares into code, it also provides a test suite that replicates those exact user flows. This ensures 100% behavioral parity between your legacy system and your new React application.

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Is Replay secure for enterprise use?#

Modernizing legacy systems often involves sensitive data. Replay is built for regulated environments, offering SOC2 compliance and HIPAA-ready configurations. For organizations with strict data residency requirements, Replay is available for On-Premise deployment.

You can safely process videos of internal tools, banking portals, or healthcare dashboards. Replay’s engine focuses on the UI structure and behavioral patterns, allowing you to redact or ignore sensitive PII (Personally Identifiable Information) during the extraction process.

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Frequently Asked Questions#

What file formats does Replay support for code extraction?#

Replay supports all standard video formats, including MP4, MOV, and WebM. For the best results when converting screen shares into code, we recommend high-resolution recordings (1080p or 4K) at 30 or 60 FPS. This provides the AI engine with the most granular data for transition and animation extraction.

Does Replay work with complex state management like Redux?#

Yes. While Replay primarily extracts the UI and component logic, it can infer state patterns from the visual behavior of the application. If it detects complex data tables or multi-step forms, it will generate the necessary React hooks (

, ) to manage that state. You can also prompt the Agentic Editor to wrap extracted components in specific state providers.

How does Replay handle custom CSS and unique brand styles?#

Replay uses a proprietary "Visual Tokenization" engine. It doesn't just guess colors; it samples the entire video to build a consistent palette. It identifies recurring spacing units, border radii, and shadow depths. These are then exported as a Tailwind configuration or CSS variables, ensuring that converting screen shares into code results in a maintainable, themed output.

Can I use Replay to convert Figma prototypes into code?#

Absolutely. Replay’s Figma Plugin allows you to extract design tokens directly. If you have a video of a Figma prototype, Replay treats it exactly like a recording of a live app, allowing you to turn a high-fidelity prototype into a deployed React application in a fraction of the time.

How much faster is Replay compared to manual coding?#

On average, Replay provides a 10x speed increase. A task that typically takes a senior developer a full week (40 hours)—such as reverse engineering a complex legacy dashboard—can be completed in about 4 hours using Replay. This includes the time for recording, extraction, and final polish in the Agentic Editor.

Ready to ship faster? Try Replay free — from video to production code in minutes.