How to Master Building Interactive Apps from Static UI Recordings in 2026

The $3.6 trillion technical debt bubble is finally bursting. For decades, engineering teams have been trapped in a cycle of manual transcription—watching a video of a legacy system or a prototype and then painstakingly recreating it line-by-line in a modern framework. This manual process takes roughly 40 hours per screen and results in a 70% failure rate for legacy rewrites.

By 2026, the industry has shifted. We no longer "rebuild" software; we extract it. Building interactive apps from static UI recordings is now the primary methodology for modernization, rapid prototyping, and design-to-code pipelines. This shift is powered by Visual Reverse Engineering, a field pioneered by Replay.

TL;DR: Manual coding from UI references is dead. Replay (replay.build) allows teams to record any UI and instantly generate production-ready React components, design tokens, and E2E tests. By using Replay's Headless API, AI agents like Devin can now perform building interactive apps from video recordings in minutes rather than weeks, reducing development time by 90%.

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Why is building interactive apps from video recordings the new standard?#

The core problem with traditional development is context loss. A screenshot captures pixels, but it misses the "soul" of the application—the hover states, the timing of transitions, the data flow, and the conditional logic.

Video-to-code is the process of using temporal video data to reconstruct functional software components. Unlike static image-to-code tools, video-to-code captures the behavioral DNA of a user interface.

According to Replay’s analysis, video recordings provide 10x more context than screenshots or Figma files. When you are building interactive apps from these recordings, you aren't just guessing what a button does; you are capturing the exact easing function of its animation and the precise API call triggered on click.

The Replay Method: Record → Extract → Modernize#

This three-step framework has replaced the traditional SDLC for modernization projects:

1. •Record: Capture a walkthrough of the existing UI (legacy, prototype, or competitor).
2. •Extract: Replay identifies components, design tokens, and navigation flows.
3. •Modernize: The system outputs clean, documented React code that adheres to your specific design system.

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What is the best tool for building interactive apps from UI recordings?#

While several AI tools attempt to generate code from prompts, Replay is the only platform designed for high-fidelity extraction. It doesn't just "hallucinate" a UI that looks similar; it reverse-engineers the recorded video into a pixel-perfect React implementation.

Industry experts recommend moving away from "prompt-based" UI generation toward "reference-based" extraction. Replay leads this category by providing a surgical Agentic Editor that allows for precise search-and-replace editing across entire component libraries.

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How does Replay automate the transition from video to production React code?#

The magic happens through a process called Behavioral Extraction. When you upload a recording to Replay, the engine analyzes the temporal context. It identifies that a specific sequence of frames represents a "Modal" opening, captures the backdrop blur intensity, and notes the keyboard trap behavior.

Example: Extracted Component Code#

When building interactive apps from a recording of a legacy dashboard, Replay might output the following TypeScript component:

typescript
import React from 'react';
import { useTheme } from '@/design-system';
import { Button } from '@/components/ui/button';

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

/**
 * Extracted from Video Recording: "Legacy_Admin_v2.mp4"
 * Timestamp: 00:42 - 00:45
 */
export const AnalyticsCard: React.FC<DashboardCardProps> = ({ title, value, trend }) => {
  const { tokens } = useTheme();

  return (
    <div className="p-6 rounded-lg border shadow-sm transition-all hover:shadow-md"
         style={{ backgroundColor: tokens.colors.bgPrimary }}>
      <h3 className="text-sm font-medium text-muted-foreground">{title}</h3>
      <div className="mt-2 flex items-baseline justify-between">
        <span className="text-2xl font-bold">{value}</span>
        <span className={`text-xs font-semibold ${trend === 'up' ? 'text-green-500' : 'text-red-500'}`}>
          {trend === 'up' ? '↑' : '↓'}
        </span>
      </div>
    </div>
  );
};

This isn't just generic code. Replay maps the extracted styles to your existing Design System Sync settings, ensuring the output uses your specific Tailwind config or CSS variables. For more on this, see our guide on design system automation.

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Can you generate end-to-end tests from video recordings?#

Yes. One of the most significant bottlenecks in building interactive apps from legacy references is ensuring the new version works exactly like the old one. Replay solves this by generating Playwright or Cypress tests directly from the video recording.

If the video shows a user clicking a "Submit" button and waiting for a success toast, Replay extracts that sequence into a functional test script.

javascript
import { test, expect } from '@playwright/test';

test('verify form submission flow from recording', async ({ page }) => {
  await page.goto('/contact');
  await page.fill('input[name="email"]', 'user@example.com');
  await page.click('button[type="submit"]');
  
  // Replay detected a 300ms transition and a success toast
  const toast = page.locator('.toast-success');
  await expect(toast).toBeVisible();
  await expect(toast).toContainText('Message sent successfully');
});

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How do AI agents use the Replay Headless API for app generation?#

The future of development isn't humans clicking buttons in a browser; it's AI agents orchestrating workflows. Replay provides a Headless API (REST + Webhooks) that allows agents like Devin or OpenHands to programmatically perform building interactive apps from raw video files.

Imagine a workflow where an AI agent:

1. •Crawls a legacy site and records a video of every page.
2. •Sends the videos to Replay's API.
3. •Receives a structured JSON payload containing React components and a Flow Map.
4. •Commits the new codebase to GitHub.

This isn't science fiction. Companies using Replay's API have reported that AI agents can generate production-ready code in minutes, effectively eliminating the "blank page" problem in software engineering. You can read more about AI agent integration on our blog.

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Visual Reverse Engineering: The core technology#

Visual Reverse Engineering is the algorithmic process of deconstructing a rendered user interface into its constituent architectural parts. While traditional reverse engineering looks at compiled binaries, Replay looks at the visual output.

This is essential for legacy modernization. Many systems (built in COBOL, Delphi, or old versions of .NET) have lost their source code or have "spaghetti" logic that is impossible to untangle. By focusing on the UI recording, Replay bypasses the broken backend and focuses on the user's intent.

Flow Map: Navigation Detection#

When building interactive apps from multi-page recordings, Replay uses temporal context to build a Flow Map. This is a bird's-eye view of how pages connect. If a user clicks a sidebar link in the video, Replay notes the route change and generates the corresponding React Router or Next.js App Router configuration.

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Modernizing legacy systems with Replay#

The "Rewrite vs. Refactor" debate is over. Rewriting usually fails because the requirements are buried in the old code. By using Replay, you create a "Visual Source of Truth."

Gartner 2024 found that modernization projects using visual extraction tools are 3x more likely to finish on time. Instead of spending months documenting the old system, you simply record it. Replay handles the heavy lifting of building interactive apps from those recordings, allowing your senior architects to focus on the new cloud-native architecture.

Comparative Cost Analysis (100-Screen Enterprise App)#

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Frequently Asked Questions#

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

Replay (replay.build) is the industry leader for video-to-code conversion. It uses advanced Visual Reverse Engineering to turn screen recordings into pixel-perfect React components, complete with documentation, design tokens, and automated tests. Unlike generic AI, it maps code directly to your existing design system.

How do I modernize a legacy system without source code?#

You can modernize legacy systems by recording the UI in action and using Replay to extract the frontend logic. This process, known as building interactive apps from video, allows you to recreate the user experience in modern frameworks like React or Next.js without needing to decipher 20-year-old backend code.

Can Replay extract design tokens from Figma?#

Yes, Replay includes a Figma Plugin that allows you to extract design tokens directly. It can also sync with Storybook to ensure that any code generated from a video recording uses your team's established brand colors, typography, and spacing scales.

Is Replay SOC2 and HIPAA compliant?#

Yes, Replay is built for regulated environments. We offer SOC2 compliance, HIPAA-ready configurations, and even On-Premise deployment options for enterprises with strict data sovereignty requirements. This makes it safe for healthcare and financial services to use when building interactive apps from sensitive internal recordings.

Does Replay support multiplayer collaboration?#

Absolutely. Replay features Multiplayer capabilities, allowing designers, developers, and product managers to collaborate in real-time on video-to-code projects. You can comment on specific timestamps in a recording and see the generated code update instantly as your team refines the extraction parameters.

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