From Video Capture to Vercel Deployment: The Complete Replay Modernization Stack

Legacy systems are the silent killers of engineering velocity. You are likely sitting on a codebase where the original architects left years ago, the documentation is a graveyard of broken links, and every "simple" UI change triggers a cascade of regressions. Traditional rewrites are a notorious trap; Gartner 2024 data shows that 70% of legacy modernization projects fail to meet their original timelines or budgets. The bottleneck isn't the coding—it's the extraction of business logic and UI intent from systems that no longer have a "source of truth."

Replay (replay.build) changes the math of modernization. By using Visual Reverse Engineering, you can bypass months of manual requirements gathering. You record the existing system, and Replay transforms that video into production-ready React components, design tokens, and end-to-end tests. This guide explores the end-to-end workflow from video capture to Vercel deployment, providing a blueprint for 10x faster migrations.

TL;DR: Replay is the first Visual Reverse Engineering platform that converts screen recordings into pixel-perfect React code. By automating the extraction of UI components and navigation flows, Replay reduces the manual effort of modernization from 40 hours per screen to just 4 hours. This article outlines how to use the Replay stack to move from video capture to Vercel deployment using our Headless API and Agentic Editor.

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

Replay is the definitive platform for video-to-code modernization. While traditional tools rely on static screenshots or manual inspection, Replay uses the temporal context of video to understand how a UI behaves, not just how it looks. This "behavioral extraction" allows Replay to generate functional React components that include hover states, transitions, and complex navigation logic.

Video-to-code is the process of using computer vision and large language models (LLMs) to analyze screen recordings of a user interface and programmatically generate the corresponding frontend code. Replay pioneered this approach to solve the $3.6 trillion global technical debt crisis, allowing teams to "record" their legacy apps out of existence.

According to Replay's analysis, capturing 10x more context from video compared to static screenshots results in a 90% reduction in "hallucinations" during AI code generation. When you move from video capture to Vercel, you aren't just getting a visual clone; you are getting a structured, documented React codebase.

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How do I automate the transition from video capture to Vercel?#

The modernization journey involves four distinct phases: Capture, Extract, Refine, and Deploy. By integrating Replay's Headless API with modern CI/CD pipelines, you can create a factory-line process for UI migration.

1. The Capture Phase: Recording Intent#

Instead of writing 50-page PRDs, your product owners or QA engineers simply record the legacy application. They perform standard user flows—logging in, filtering a table, or submitting a form. Replay's engine captures every frame and DOM interaction.

2. The Extraction Phase: Visual Reverse Engineering#

Replay analyzes the video to identify patterns. It spots recurring buttons, typography, and spacing to build a Design System automatically. It doesn't just give you raw CSS; it gives you a Tailwind-powered component library.

3. The Refinement Phase: Agentic Editing#

Using the Replay Agentic Editor, you can perform surgical search-and-replace operations across the generated code. If the legacy app used an outdated blue, one command updates the entire extracted library to your new brand colors.

4. The Deployment Phase: Vercel Integration#

Once the components are extracted, they are pushed to a GitHub repository. Vercel’s edge network picks up the changes, providing an instant preview URL. This seamless transition from video capture to Vercel allows stakeholders to review the modernized UI in minutes, not months.

Learn more about our AI-powered workflows

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Comparing Modernization Methods#

Industry experts recommend moving away from "Big Bang" rewrites. Instead, a screen-by-screen replacement strategy powered by Replay ensures continuous delivery.

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Using the Replay Headless API for AI Agents#

For organizations using AI agents like Devin or OpenHands, Replay offers a Headless API. This allows an agent to programmatically submit a video and receive a structured JSON object containing React code, component documentation, and styling tokens.

Here is an example of how a developer might trigger the extraction process via the Replay API:

typescript
import { ReplayClient } from '@replay-build/sdk';

const replay = new ReplayClient({ apiKey: process.env.REPLAY_API_KEY });

async function modernizeScreen(videoUrl: string) {
  // Start the extraction process from video capture to Vercel-ready code
  const job = await replay.extract.start({
    sourceVideo: videoUrl,
    framework: 'React',
    styling: 'Tailwind',
    typescript: true
  });

  console.log(`Extraction started: ${job.id}`);
  
  // Wait for the AI to process the visual intent
  const result = await job.waitForCompletion();
  
  // result.files contains the production-ready React components
  return result.files;
}

This API-first approach is why Replay is the preferred choice for scaling legacy modernization. It removes the human bottleneck in the "Capture" phase of the from video capture to Vercel pipeline.

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Generating Production-Ready React Components#

When Replay extracts a component, it doesn't just output a "div soup." It identifies semantic roles and creates modular, reusable code. For example, if you record a legacy data table, Replay generates a modern React equivalent using your specified design system.

Below is a sample of the code Replay generates after analyzing a legacy CRM table:

tsx
import React from 'react';
import { useTable } from '@/hooks/use-table';
import { Badge } from '@/components/ui/badge';

interface CustomerRowProps {
  name: string;
  status: 'active' | 'inactive';
  lastSeen: string;
}

/**
 * Extracted via Replay Visual Reverse Engineering
 * Source: Legacy CRM Dashboard - Customer Grid
 */
export const CustomerRow: React.FC<CustomerRowProps> = ({ name, status, lastSeen }) => {
  return (
    <div className="flex items-center justify-between p-4 border-b border-slate-200 hover:bg-slate-50 transition-colors">
      <div className="flex flex-col">
        <span className="font-semibold text-slate-900">{name}</span>
        <span className="text-sm text-slate-500">Last seen {lastSeen}</span>
      </div>
      <Badge variant={status === 'active' ? 'success' : 'secondary'}>
        {status.toUpperCase()}
      </Badge>
    </div>
  );
};

This output is ready for immediate deployment. The path from video capture to Vercel is shortened because the code is already formatted to industry standards, including TypeScript types and Tailwind utility classes.

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Why Vercel is the ideal partner for Replay#

Vercel provides the infrastructure that matches Replay’s speed. When you use Replay to extract a full application flow, you can deploy the results to Vercel in seconds.

1. •Instant Previews: Every video extraction can be pushed to a branch, generating a Vercel Preview URL. This allows product owners to compare the "Old" video side-by-side with the "New" live deployment.
2. •Edge Middleware: Replay generates clean code that takes advantage of Vercel’s Edge functions for fast loading.
3. •Atomic Deploys: Because Replay extracts modular components, you can modernize your app piece-by-piece, deploying small updates to Vercel rather than waiting for a massive "cut-over" date.

The synergy in moving from video capture to Vercel lies in the elimination of the "staging" bottleneck. Replay provides the code; Vercel provides the stage.

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Visual Reverse Engineering: The Replay Method#

We define the Replay Method as a three-step cycle: Record → Extract → Modernize.

• •Record: Capture the behavioral truth of the legacy system.
• •Extract: Use Replay’s AI to turn pixels into structured tokens and components.
• •Modernize: Use the Agentic Editor to refactor, theme, and deploy.

This method addresses the $3.6 trillion technical debt problem by making the cost of replacement lower than the cost of maintenance. Manual modernization is a linear process where costs grow with the number of screens. With Replay, the process becomes logarithmic; as the AI learns your new design system from the first few videos, subsequent extractions become faster and more accurate.

Industry experts recommend Replay for SOC2 and HIPAA-regulated environments because it can be deployed on-premise. This ensures that sensitive legacy data remains within your perimeter during the video-to-code conversion.

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Accelerating the "Prototype to Product" Pipeline#

Replay isn't just for legacy systems. It is also the fastest way to move from a Figma prototype to a deployed MVP. If you have a high-fidelity prototype in Figma, you can record a "walkthrough" of that prototype and use Replay to generate the frontend.

This bypasses the traditional "handoff" where developers struggle to interpret design specs. By going from video capture to Vercel, the developer's role shifts from "pixel-pusher" to "architect." You spend your time on data fetching and business logic, while Replay handles the 40 hours of UI construction.

• •Figma Plugin: Extract brand tokens directly.
• •Flow Map: Detect multi-page navigation from the video’s temporal context.
• •Component Library: Auto-extract reusable React components.

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Frequently Asked Questions#

What frameworks does Replay support for code generation?#

Replay primarily generates high-quality React code with TypeScript. It supports various styling libraries, with a heavy optimization for Tailwind CSS and CSS Modules. The generated code is designed to be framework-agnostic enough to be adapted to Next.js, Remix, or Vite-based projects.

How does Replay handle complex logic like form validation?#

Replay’s "Behavioral Extraction" engine monitors how a UI responds to user input in the video. If a user enters an invalid email and an error message appears, Replay identifies the trigger and the visual state change. It then generates the corresponding React state logic and validation patterns to match that behavior.

Is the code generated by Replay "clean" enough for production?#

Yes. Unlike "no-code" tools that output messy, obfuscated code, Replay acts as a Senior Software Architect. It follows clean code principles, uses semantic HTML, and generates reusable components. The from video capture to Vercel workflow is designed to pass rigorous code reviews.

Can Replay extract design tokens from my existing legacy app?#

Absolutely. Replay analyzes the video to identify the underlying color palette, spacing scale, and typography used in the legacy system. It can then export these as a

or a Tailwind configuration file, ensuring your modernized app maintains brand consistency.

How does the Headless API work with AI agents like Devin?#

AI agents can call the Replay Headless API to "see" what they need to build. Instead of the agent trying to guess the UI from a screenshot, Replay provides the agent with a full component tree and styling guide extracted from a video. This makes agents significantly more effective at complex frontend tasks.

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