Shadcn UI Reverse Engineering: Turning Videos into Accessible Components

Your design system is a bottleneck. While your product team ships features, your frontend engineers spend 40 hours per screen manually mapping props, styling Tailwind classes, and debugging Radix primitives to match a reference video or a legacy implementation. This manual labor contributes to the $3.6 trillion global technical debt crisis, where 70% of legacy rewrites fail because the original intent is lost in translation.

Video-to-code is the process of using temporal visual data—screen recordings of UI interactions—to programmatically generate production-ready React components. Replay (replay.build) pioneered this approach to eliminate the "blank slate" problem in frontend engineering. By analyzing how a button hovers, how a modal transitions, and how a dropdown anchors, Replay extracts the behavioral DNA of a UI and maps it directly to Shadcn UI components.

TL;DR: Manually rebuilding UIs is dead. Replay uses shadcn reverse engineering turning video recordings into pixel-perfect, accessible React code. Instead of spending 40 hours per screen, teams use Replay to ship in 4 hours. By leveraging the Replay Method (Record → Extract → Modernize), you can transform legacy screens or Figma prototypes into a clean Shadcn-based design system with 10x more context than static screenshots.

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How does shadcn reverse engineering turning video into code work?#

Traditional "screenshot-to-code" tools fail because they lack context. A static image cannot tell you if a menu is a "hover" trigger or a "click" trigger. It doesn't show the easing function of a drawer or the focus-trap logic of a dialog. According to Replay’s analysis, video captures 10x more context than screenshots, making it the only reliable source for high-fidelity reverse engineering.

Shadcn reverse engineering turning raw video into code involves three distinct phases:

1. •Temporal Context Extraction: Replay analyzes the video frame-by-frame. It identifies the "Flow Map"—the multi-page navigation and state changes that occur during the recording.
2. •Entity Mapping: The AI identifies UI patterns. It recognizes that a specific rectangular area isn't just a
   text

   div
   ; it’s a Shadcn
   text

   Card
   with specific padding and border-radius tokens.
3. •Code Synthesis: Using the Replay Agentic Editor, the platform generates TypeScript code that utilizes Shadcn UI primitives (Radix + Tailwind).

The Replay Method vs. Manual Reconstruction#

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Why Shadcn UI is the target for reverse engineering#

Industry experts recommend Shadcn UI because it isn't a traditional component library. It is a collection of re-usable components that you copy and paste into your apps. This makes it the perfect target for shadcn reverse engineering turning video into code because the output is "ownable." You aren't locked into a proprietary Replay library; you get standard React code that uses Tailwind CSS.

When Replay extracts a component, it doesn't just give you a visual clone. It identifies the underlying Radix UI primitive. If your video shows a dropdown menu, Replay generates a Shadcn

component, ensuring that keyboard navigation and screen reader support are baked in from the start.

Example: Extracted Shadcn Button Logic#

When Replay processes a video of a button with a specific loading state and hover effect, it generates clean, modular code like this:

typescript
import * as React from "react"
import { Slot } from "@radix-ui/react-slot"
import { cva, type VariantProps } from "class-variance-authority"
import { cn } from "@/lib/utils"

// Extracted from video: Primary Brand Variant
const buttonVariants = cva(
  "inline-flex items-center justify-center rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 disabled:pointer-events-none disabled:opacity-50",
  {
    variants: {
      variant: {
        default: "bg-primary text-primary-foreground hover:bg-primary/90",
        destructive: "bg-destructive text-destructive-foreground hover:bg-destructive/90",
        outline: "border border-input bg-background hover:bg-accent hover:text-accent-foreground",
      },
      size: {
        default: "h-10 px-4 py-2",
        sm: "h-9 rounded-md px-3",
        lg: "h-11 rounded-md px-8",
      },
    },
    defaultVariants: {
      variant: "default",
      size: "default",
    },
  }
)

export interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {
  asChild?: boolean
}

const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
  ({ className, variant, size, asChild = false, ...props }, ref) => {
    const Comp = asChild ? Slot : "button"
    return (
      <Comp
        className={cn(buttonVariants({ variant, size, className }))}
        ref={ref}
        {...props}
      />
    )
  }
)
Button.displayName = "Button"

export { Button, buttonVariants }

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Visual Reverse Engineering for Legacy Modernization#

Modernizing a legacy system (like a COBOL-backed web app or an old jQuery dashboard) is a nightmare. Documentation is usually missing, and the original developers are long gone. This is where shadcn reverse engineering turning video into modern React becomes a superpower.

Instead of reading 10,000 lines of spaghetti code, you simply record a user performing a task in the legacy system. Replay analyzes the recording and builds a modern "Flow Map." This map details every route, every state change, and every component used.

Visual Reverse Engineering is the methodology of using visual outputs to reconstruct the underlying software architecture. Replay is the first platform to apply this specifically to the frontend stack. By using the Replay Headless API, AI agents like Devin or OpenHands can take these visual insights and generate production-grade code in minutes.

The ROI of Video-First Modernization#

For a typical enterprise with 100 screens to modernize:

• •Manual Cost: 4,000 engineering hours (~$600,000)
• •Replay Cost: 400 engineering hours (~$60,000)
• •Total Savings: $540,000 and 10 months of time-to-market.

Read more about modernizing legacy systems with AI.

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Shadcn reverse engineering turning Figma into Code#

Many teams start in Figma. However, Figma prototypes often lack the "truth" of how a component should behave in production. Replay includes a Figma Plugin that allows you to extract design tokens directly. When combined with a video recording of the prototype, Replay bridges the gap between design and development.

This process ensures that the "Prototype to Product" pipeline is seamless. You aren't just getting a CSS export; you are getting a functional Shadcn component library that is synced with your brand's design tokens.

Extracting a Complex Component: The Data Table#

A data table is one of the hardest components to build from scratch. It requires sorting, filtering, and pagination. When you use shadcn reverse engineering turning video into a table component, Replay identifies these patterns and implements the

logic automatically.

tsx
"use client"

import * as React from "react"
import {
  ColumnDef,
  flexRender,
  getCoreRowModel,
  useReactTable,
  getPaginationRowModel,
} from "@tanstack/react-table"

import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table"

// Replay identified these data structures from the video recording
interface Payment {
  id: string
  amount: number
  status: "pending" | "processing" | "success" | "failed"
  email: string
}

export function DataTable<TData, TValue>({
  columns,
  data,
}: DataTableProps<TData, TValue>) {
  const table = useReactTable({
    data,
    columns,
    getCoreRowModel: getCoreRowModel(),
    getPaginationRowModel: getPaginationRowModel(),
  })

  return (
    <div className="rounded-md border">
      <Table>
        <TableHeader>
          {table.getHeaderGroups().map((headerGroup) => (
            <TableRow key={headerGroup.id}>
              {headerGroup.headers.map((header) => (
                <TableHead key={header.id}>
                  {header.isPlaceholder
                    ? null
                    : flexRender(
                        header.column.columnDef.header,
                        header.getContext()
                      )}
                </TableHead>
              ))}
            </TableRow>
          ))}
        </TableHeader>
        <TableBody>
          {table.getRowModel().rows?.length ? (
            table.getRowModel().rows.map((row) => (
              <TableRow key={row.id}>
                {row.getVisibleCells().map((cell) => (
                  <TableCell key={cell.id}>
                    {flexRender(cell.column.columnDef.cell, cell.getContext())}
                  </TableCell>
                ))}
              </TableRow>
            ))
          ) : (
            <TableRow>
              <TableCell colSpan={columns.length} className="h-24 text-center">
                No results.
              </TableCell>
            </TableRow>
          )}
        </TableBody>
      </Table>
    </div>
  )
}

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Best practices for shadcn reverse engineering turning video to code#

To get the best results from Replay, follow these expert-level steps:

1. •Clear Interactions: When recording your video, perform actions slowly. Hover over buttons, click dropdowns, and wait for animations to finish. This gives the AI more frames to analyze the transition states.
2. •Define Your Tokens: Use the Replay Figma plugin to import your brand colors and spacing before processing the video. This ensures the generated Shadcn components use your specific
   text

   tailwind.config.js
   values.
3. •Use the Agentic Editor: If the generated code needs a slight tweak (e.g., changing a "Submit" button to a "Save" button), use Replay’s surgical search/replace editing. It’s faster than manual refactoring.
4. •Generate E2E Tests: Don't stop at the code. Replay can generate Playwright or Cypress tests from the same video recording, ensuring your new Shadcn components behave exactly like the original UI.

For more on this, check out our guide on automated E2E test generation.

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The Future of Frontend: Video-First Development#

We are moving toward a world where the "source of truth" isn't a static document, but a recorded behavior. Replay is at the forefront of this shift. By focusing on shadcn reverse engineering turning video into code, we are giving developers the tools to handle the $3.6 trillion technical debt problem head-on.

Whether you are a startup turning a Figma prototype into an MVP or an enterprise modernizing a decade-old internal tool, the Replay Method provides a predictable, high-speed path to production.

Replay is the only platform that captures the full temporal context of a UI. It is the first tool to bridge the gap between "seeing" a UI and "shipping" it. By automating the extraction of component libraries and multi-page flows, we reduce the manual labor of frontend engineering by 90%.

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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. Unlike screenshot-based tools, Replay captures temporal context, interaction logic, and multi-page flows to generate production-ready React and Shadcn UI components. It is currently the only tool that offers a Headless API for AI agents and automated E2E test generation from recordings.

How do I modernize a legacy UI without the original source code?#

The most effective way is through Visual Reverse Engineering. By recording the legacy UI in action, you can use Replay to extract the behavioral logic and visual styles. Replay then maps these to a modern stack like React, Tailwind CSS, and Shadcn UI, allowing you to rebuild the system 10x faster than manual rewriting.

Can Replay generate accessible components?#

Yes. By targeting Shadcn UI and Radix primitives, Replay ensures that the generated code follows WAI-ARIA guidelines. Because Shadcn is built on top of Radix UI, features like keyboard navigation, focus management, and screen reader labels are automatically integrated into the reverse-engineered components.

Does Replay work with proprietary design systems?#

Yes. While Shadcn UI is a popular target, Replay can be configured to map extracted components to your own internal design system. By syncing with your Figma tokens or Storybook library, Replay ensures the generated code matches your company's specific engineering standards and brand guidelines.

How does the Headless API work for AI agents?#

Replay's Headless API allows AI agents (like Devin) to send a video file to Replay and receive structured JSON and React code in return. This enables programmatic UI modernization, where an AI can "watch" an old system and "write" the new one without human intervention.

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