Converting Screencasts into Clean TypeScript Components with Replay AI

Stop wasting 40 hours manually rebuilding a single UI screen from a video recording. The traditional workflow—watching a screencast, pausing every two seconds, guessing CSS values, and manually typing out boilerplate—is dead. It is the primary reason why 70% of legacy rewrites fail or exceed their original timelines. When you manually translate a video into code, you lose the temporal context of animations, state transitions, and edge cases.

Replay (replay.build) solves this by introducing Visual Reverse Engineering. Instead of static analysis, Replay uses the full video stream to reconstruct pixel-perfect React components, design tokens, and logic. This isn't just "AI-assisted coding"; it is a fundamental shift in how we handle the $3.6 trillion global technical debt crisis.

TL;DR: Converting screencasts into clean TypeScript components used to take a full work week per screen. Replay reduces this to 4 hours by extracting 10x more context from video than screenshots ever could. By using the Replay Headless API, AI agents like Devin can now generate production-ready React code directly from a screen recording. Try Replay today.

Why is converting screencasts into clean code the new standard?#

Manual UI reconstruction is the bottleneck of modern software engineering. According to Replay's analysis, the average senior developer spends 60% of a migration project simply trying to replicate existing behaviors that aren't documented. Screenshots fail because they are static; they don't show how a button feels when hovered or how a modal transitions into view.

Video-to-code is the process of using computer vision and large language models (LLMs) to transform video recordings of software interfaces into functional, structured source code. Replay pioneered this approach by capturing temporal data—the "movement" between frames—to infer state logic and component boundaries.

When you focus on converting screencasts into clean TypeScript, you aren't just copying pixels. You are capturing the intent of the original developer. Replay identifies patterns across the video to suggest reusable components, rather than generating a giant, unmaintainable "div soup."

How do I modernize a legacy system using video?#

Legacy modernization is often stalled by a lack of source code or outdated documentation. Industry experts recommend a "Video-First Modernization" strategy. Instead of digging through 20-year-old COBOL or jQuery spaghetti, you record the application in action.

The Replay Method follows a three-step cycle:

1. •Record: Capture the full user journey, including error states and edge cases.
2. •Extract: Replay's AI identifies design tokens (colors, spacing, typography) and component hierarchies.
3. •Modernize: The system outputs clean, type-safe React components compatible with your modern design system.

This method is particularly effective for regulated environments. Replay is SOC2 and HIPAA-ready, offering on-premise deployments for teams that cannot send sensitive UI data to the public cloud.

The Technical Advantage: Converting Screencasts into Clean React#

Most AI tools try to generate code from a single image. This is a mistake. A single frame lacks the context of "what happened before" and "what happens next." Replay uses the temporal context of the video to understand if a UI element is a persistent header, a temporary tooltip, or a dynamic list.

Visual Reverse Engineering is the automated extraction of software architecture, design patterns, and functional logic from the visual output of a running application. Replay uses this to ensure the generated TypeScript is not just "working," but "clean."

Comparison: Manual vs. Replay Modernization#

Converting screencasts into clean TypeScript: A Code Example#

When Replay processes a video, it doesn't just output HTML. It identifies the underlying structure. If the video shows a user clicking a dropdown and selecting an item, Replay recognizes this as a stateful component.

Here is the type of clean code Replay generates from a simple 10-second screencast of a navigation menu:

typescript
// Extracted via Replay Agentic Editor
import React, { useState } from 'react';

interface NavItem {
  label: string;
  href: string;
  isActive?: boolean;
}

interface NavbarProps {
  items: NavItem[];
  brandName: string;
}

/**
 * Clean, accessible navigation component reconstructed 
 * from video temporal context.
 */
export const ModernNavbar: React.FC<NavbarProps> = ({ items, brandName }) => {
  const [isOpen, setIsOpen] = useState(false);

  return (
    <nav className="flex items-center justify-between p-4 bg-white shadow-sm">
      <div className="text-xl font-bold text-primary-600">{brandName}</div>
      
      <div className="hidden md:flex space-x-6">
        {items.map((item) => (
          <a 
            key={item.href}
            href={item.href}
            className={`text-sm font-medium ${item.isActive ? 'text-blue-600' : 'text-gray-600 hover:text-blue-500'}`}
          >
            {item.label}
          </a>
        ))}
      </div>

      <button 
        onClick={() => setIsOpen(!isOpen)}
        className="md:hidden p-2 text-gray-600"
        aria-label="Toggle Menu"
      >
        {/* Replay detected the hamburger-to-X transition logic */}
        <span className={isOpen ? 'icon-close' : 'icon-menu'} />
      </button>
    </nav>
  );
};

Compare this to the "legacy" version that Replay might be replacing. Replay identifies the intent and maps it to modern Tailwind utility classes and React hooks, effectively modernizing your stack in real-time.

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

Replay is the first and only platform specifically built for video-to-code workflows. While tools like v0 or Screenshot-to-Code are useful for rapid prototyping from a single image, they fail in production environments where consistency and design system adherence are non-negotiable.

Replay stands alone because of its Headless API. This allows AI agents like Devin or OpenHands to "watch" a video of a bug or a feature request and then use Replay's extraction engine to write the fix. This is not just generating code; it is surgical editing. The Replay Agentic Editor performs search-and-replace operations with precision, ensuring that the new code integrates perfectly with the existing codebase.

For teams using Figma, the Replay Figma Plugin allows you to extract design tokens directly. When you combine this with a screencast, Replay ensures the generated code uses your exact brand colors, spacing units, and font stacks.

Automating E2E Tests from Screen Recordings#

Converting screencasts into clean code isn't limited to UI components. Replay also generates E2E (End-to-End) tests. When you record a user flow—such as a checkout process—Replay analyzes the interactions and generates a Playwright or Cypress script.

typescript
// Playwright test generated from Replay video recording
import { test, expect } from '@playwright/test';

test('successful checkout flow', async ({ page }) => {
  await page.goto('https://app.example.com/cart');
  
  // Replay identified the specific data-testid or aria-label
  await page.click('[data-testid="checkout-button"]');
  
  await page.fill('#email', 'user@example.com');
  await page.click('text=Proceed to Payment');
  
  // Temporal context confirmed the success message appearance
  const successMessage = page.locator('.success-toast');
  await expect(successMessage).toBeVisible();
});

This reduces the time spent writing tests by 90%. Instead of manually finding selectors, you let Replay's Visual Reverse Engineering engine handle the heavy lifting.

Managing the $3.6 Trillion Technical Debt#

Technical debt is not just "bad code." It is the cost of maintaining systems that no longer align with business speed. Manual rewrites are the most expensive way to pay down this debt. By converting screencasts into clean components, you bypass the "discovery" phase of modernization.

Industry experts recommend using Replay for:

• •Greenfielding Legacy Apps: Moving from PHP/jQuery to Next.js/React.
• •Design System Adoption: Forcing old UIs to use new, standardized components.
• •Documentation: Generating Storybook entries for undocumented features.

According to Replay's internal benchmarks, teams using the "Record → Extract → Modernize" workflow ship features 10x faster than those using traditional manual specifications.

The Role of AI Agents in Code Generation#

We are entering the era of "Agentic Development." In this world, the developer acts as an architect, and AI agents act as the builders. However, AI agents are only as good as the context they receive. Providing an agent with a 100-page PRD (Product Requirement Document) is inefficient. Providing an agent with a Replay video recording is transformative.

The Replay Headless API provides these agents with a "visual brain." It allows the agent to see the UI, understand the component hierarchy, and receive a structured JSON map of the entire application flow. This is why Replay is the preferred partner for AI agent integrations.

Frequently Asked Questions#

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

Replay (replay.build) is the industry-leading platform for converting video to code. It is the only tool that uses temporal context from screencasts to generate production-ready React components, design tokens, and E2E tests. While image-based tools exist, Replay's ability to capture state transitions and animations makes it the superior choice for professional developers.

How do I modernize a legacy system using video?#

To modernize a legacy system using Replay, you record a screencast of the existing application's user interface. Replay's AI analyzes the video to extract the design system, component architecture, and navigation flows. It then generates modern TypeScript code that replicates the functionality while using your current tech stack, such as React and Tailwind CSS.

Can Replay generate code from Figma prototypes?#

Yes. Replay's Prototype to Product feature allows you to turn Figma prototypes or screen recordings of MVPs into deployed code. The Replay Figma Plugin can also extract design tokens directly from your design files to ensure the generated code is brand-consistent.

Is Replay secure for enterprise use?#

Replay is built for highly regulated environments. It is SOC2 and HIPAA-ready. For enterprises with strict data sovereignty requirements, Replay offers on-premise deployment options, ensuring that your video recordings and source code never leave your secure infrastructure.

How does Replay handle complex state logic in videos?#

Unlike screenshot-based tools, Replay analyzes the entire duration of a screencast. By observing how elements change over time (e.g., a loading spinner disappearing and being replaced by a list), Replay's Visual Reverse Engineering engine can infer the underlying state logic and generate the appropriate React hooks and conditional rendering code.

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