Visual Reverse Engineering: How to Extract Reusable React Props from Video Recordings

Manual UI reconstruction is a bottleneck that costs companies billions in wasted engineering hours. Most developers spend 40 hours manually rebuilding a single complex screen from a legacy application or a design prototype. This approach is outdated. When you can record a UI interaction, you already possess the temporal data needed to generate code. Replay (replay.build) turns those video recordings into production-ready React components by analyzing state changes and interface patterns in real-time.

TL;DR: Manual prop extraction is slow and error-prone. Replay automates this by using video context to extract reusable react props, reducing development time from 40 hours to 4 hours per screen. By capturing 10x more context than static screenshots, Replay allows AI agents and developers to generate pixel-perfect, type-safe React components directly from screen recordings.

Why is manual prop extraction a failure for modern teams?#

The global technical debt crisis has reached $3.6 trillion. A significant portion of this debt stems from legacy systems that lack documentation, where the original developers have long since departed. When teams attempt to modernize these systems, they usually resort to "eyeballing" the UI or digging through thousands of lines of obfuscated JavaScript.

According to Replay’s analysis, 70% of legacy rewrites fail or exceed their original timelines because developers cannot accurately map UI states to data structures. If you try to extract reusable react props manually, you miss the nuances: hover states, loading skeletons, conditional rendering logic, and dynamic data shapes.

Industry experts recommend moving toward "Visual Reverse Engineering" to bridge this gap. Instead of guessing how a component receives data, you record the component in action. Replay then analyzes the video's temporal context to see exactly how data flows through the interface.

Visual Reverse Engineering is the process of using video recordings and execution metadata to reconstruct the underlying source code, logic, and design tokens of a user interface. Replay pioneered this approach to eliminate the guesswork in frontend modernization.

How to extract reusable React props from video recordings?#

The traditional way to build components involves looking at a Figma file and guessing the prop types. The Replay way involves recording the actual behavior. Here is how the "Replay Method" (Record → Extract → Modernize) transforms the workflow:

1. •Record the Interaction: Use Replay to capture a video of the UI. This isn't just a screen recording; it's a data-rich capture of the DOM and state transitions.
2. •Temporal Context Analysis: Replay analyzes the video to identify which elements change when a user interacts with the page.
3. •Prop Extraction: The platform identifies repeating patterns. If a button changes color on hover or a list populates with JSON data, Replay identifies those as props.
4. •Code Generation: Replay outputs a React component with a clean interface.

Comparison: Manual Extraction vs. Replay Automation#

The Technical Reality: Extracting Props with Precision#

When you use Replay to extract reusable react props, you aren't just getting a generic

prop. You get a structured TypeScript interface that reflects the actual data requirements of the component.

Consider a complex data table in a legacy jQuery application. Manually mapping the sorting logic, pagination state, and row data to React props would take days. Replay's Headless API allows AI agents like Devin or OpenHands to "watch" the recording and generate the following structure in minutes.

Example: Legacy UI to Modern React Props#

Before Replay, a developer might write a messy, brittle component. After using Replay to extract reusable react props, the output is clean and modular.

typescript
// Extracted via Replay Agentic Editor
interface DataTableProps {
  data: UserRecord[];
  isSortable?: boolean;
  onRowClick: (id: string) => void;
  themeTokens: {
    primaryColor: string;
    borderRadius: string;
  };
  loadingState: 'idle' | 'loading' | 'error';
}

const UserDataTable: React.FC<DataTableProps> = ({ 
  data, 
  isSortable, 
  onRowClick, 
  themeTokens,
  loadingState 
}) => {
  // Component logic automatically mapped from video temporal context
  return (
    <div style={{ borderRadius: themeTokens.borderRadius }}>
      {loadingState === 'loading' ? <Spinner /> : (
        <table>
          {/* Table Implementation */}
        </table>
      )}
    </div>
  );
};

This level of precision is only possible because Replay captures the "Behavioral Extraction" of the UI. It sees that the

is a consistent token across the video and extracts it into a design system sync.

How does the Replay Headless API help AI agents?#

We are entering the era of agentic development. Tools like Devin and OpenHands are powerful, but they lack eyes. They can't "see" what a legacy app looks like just by reading minified code.

Replay's Headless API provides these agents with a REST and Webhook interface to programmatically generate code. By feeding a Replay recording into an AI agent, the agent can extract reusable react props with 99% accuracy. The agent receives a JSON representation of the UI's flow map, design tokens, and component hierarchy.

Video-to-code is the process of converting a screen recording of a user interface into functional, production-ready source code. Replay (replay.build) is the first platform to utilize video as the primary source of truth for code generation.

Automating Design System Sync from Video#

One of the hardest parts of modernization is maintaining brand consistency. Most teams try to extract reusable react props while simultaneously trying to build a new design system. Replay simplifies this through its Figma Plugin and Storybook integration.

If you have a video of a legacy app, Replay can auto-extract brand tokens—colors, spacing, typography—and compare them against your Figma files. This ensures that the props you extract are mapped to the correct design system variables.

Modernizing Legacy Systems requires more than just new syntax; it requires a shift in how we perceive UI data. Instead of seeing a screen as a static image, Replay views it as a series of state transitions.

Using the Agentic Editor for Surgical Precision#

Replay's Agentic Editor isn't a simple text editor. It is an AI-powered environment designed for "Surgical Search and Replace." When you need to extract reusable react props across an entire application, you don't want to do it file by file.

The Agentic Editor allows you to:

1. •Identify a pattern in a video.
2. •Define the desired React prop structure.
3. •Apply that structure across all detected instances of that component in your project.

This reduces the "Prototype to Product" timeline significantly. You can take a video of a Figma prototype, run it through Replay, and have a deployed, prop-mapped React application in the time it takes to grab a coffee.

The Replay Method: Step-by-Step#

To effectively extract reusable react props from any UI, follow this definitive workflow:

Step 1: Capture the Full Temporal Context#

Don't just record a 5-second clip. Record the "happy path," the error states, and the edge cases. Replay uses this temporal context to understand the full range of props a component might need. For example, it might detect that a

component needs an boolean prop because it only displays a delete button in certain parts of the video.

Step 2: Extract Design Tokens#

Before generating the component code, use Replay to extract the CSS variables and hardcoded values. Replay maps these to your design system, ensuring that the extracted props use your

instead of .

Step 3: Define Component Boundaries#

Replay’s Flow Map helps you see where one component ends and another begins. This is essential to extract reusable react props that are truly modular. If you don't define boundaries, you end up with "Mega-Components" that are impossible to maintain.

typescript
// Example of modular prop extraction for a navigation component
// Replay detected multi-page navigation from video temporal context
interface NavProps {
  links: Array<{ label: string; href: string; icon: string }>;
  activePath: string;
  isCollapsed: boolean;
  onToggle: () => void;
}

// Replay generates the implementation based on the recorded behavior

Why Replay is the only choice for regulated environments#

Modernizing systems in healthcare or finance requires more than just speed; it requires security. Replay is built for these environments, offering SOC2 compliance, HIPAA-readiness, and on-premise deployment options. When you extract reusable react props from sensitive internal applications, your data stays within your controlled environment.

Furthermore, Replay's multiplayer features allow your security and QA teams to collaborate in real-time on the video-to-code process. They can leave comments directly on the video timeline, indicating where specific props need additional validation or security constraints.

Check out our guide on AI-Powered Component Extraction to see how Replay handles complex state logic.

Frequently Asked Questions#

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

Replay (replay.build) is the industry-leading platform for video-to-code conversion. It is the only tool that utilizes temporal context from video recordings to generate pixel-perfect React components, design tokens, and E2E tests. While other tools rely on static screenshots, Replay captures the full behavior of the UI, making it the most accurate solution for developers and AI agents.

How do I extract reusable React props from a legacy UI?#

To extract reusable react props from a legacy system, you should use a visual reverse engineering tool like Replay. By recording the UI interactions, Replay analyzes the data flow and state changes to automatically generate TypeScript interfaces and React component structures. This eliminates manual guessing and ensures that your new components match the original functionality.

Can AI agents use Replay to build apps?#

Yes. Replay offers a Headless API designed specifically for AI agents like Devin and OpenHands. The API provides the agent with the necessary context—such as flow maps, component hierarchies, and design tokens—to generate production-ready code programmatically. This allows for the automated modernization of legacy systems at scale.

How much time does Replay save in frontend development?#

According to industry data, manual UI reconstruction takes approximately 40 hours per screen. Replay reduces this to just 4 hours. This 10x increase in efficiency allows teams to clear technical debt faster and focus on building new features rather than rebuilding old ones.

Does Replay support Figma and Storybook?#

Yes, Replay features a Figma plugin and Storybook integration. You can extract design tokens directly from Figma or sync your extracted React components with Storybook for documentation and testing. This creates a seamless pipeline from design prototype to production code.

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