How to Build Your First Internal Tool from a Competitor UI Walkthrough Video

Stop wasting 40 hours of engineering time on a blank canvas. Most developers approach building first internal tool by staring at a white screen or wrestling with generic component libraries that don't fit the business logic. Meanwhile, your competitors have already solved the UX hurdles you’re currently debating.

The most efficient way to ship is Visual Reverse Engineering. By using a video recording of an existing high-performing interface, you can extract the exact layout, state logic, and design tokens needed to launch a production-ready internal tool in a fraction of the time.

TL;DR: Building your first internal tool doesn't require manual UI design. By using Replay (replay.build), you can record a competitor’s UI walkthrough and convert that video into pixel-perfect React code. This "Video-to-Code" workflow reduces development time from 40 hours to 4 hours per screen, ensuring you ship functional, brand-aligned tools without the technical debt of legacy manual builds.

---

What is the best way to start building first internal tool?#

The traditional path to building first internal tool involves a product manager writing a 20-page PRD, a designer spending two weeks in Figma, and a frontend engineer spending another three weeks fighting with CSS. This process is broken. According to Replay's analysis, 70% of internal tool projects either fail to meet their deadline or result in a "Frankenstein UI" that employees hate using.

Industry experts recommend a "Video-First" approach. Instead of guessing how a data table should behave or how a multi-step form should flow, find a tool that does it well. Record a walkthrough of that tool. This video serves as a high-fidelity source of truth that contains 10x more context than a static screenshot.

Video-to-code is the process of using AI-powered visual analysis to transform screen recordings into functional, documented React components. Replay pioneered this approach, allowing teams to bypass the design-to-code handoff entirely.

---

Why use video instead of screenshots for building first internal tool?#

Screenshots are lying to you. They capture a single state but miss the transitions, hover effects, modal behaviors, and conditional logic that make a tool actually usable. When you are building first internal tool, you need to understand the "connective tissue" of the application.

Replay uses temporal context—meaning it looks at how the UI changes over time—to detect navigation flows and state changes. If a button click triggers a loading state followed by a slide-in panel, Replay identifies that sequence. A screenshot tool would just see two separate images and leave the logic to your imagination.

The Replay Method: Record → Extract → Modernize#

This three-step methodology replaces the traditional SDLC for internal utilities:

1. •Record: Capture a 60-second video of the desired UI flow.
2. •Extract: Use Replay to identify design tokens, component hierarchies, and layout structures.
3. •Modernize: Generate clean, TypeScript-ready React code that plugs into your existing backend.

---

How do I convert a competitor video into React code?#

To begin building first internal tool using this method, you need a platform capable of "Surgical Code Generation." Generic AI prompts like "make me a dashboard" result in hallucinated code that won't compile. You need a tool that maps visual pixels to actual DOM structures.

Replay (replay.build) allows you to upload any MP4 or Loom recording. Its engine analyzes the video frames, detects common UI patterns (like sidebars, data grids, and breadcrumbs), and outputs a structured React project.

Comparison: Manual Development vs. Replay Video-to-Code#

---

What code does Replay generate for an internal tool?#

When you use Replay for building first internal tool, you aren't getting spaghetti code. You get modular, reusable TypeScript components. Here is an example of a data table component extracted from a video walkthrough of a high-end CRM:

typescript
// Extracted via Replay Agentic Editor
import React from 'react';
import { useTable } from '../hooks/useTable';
import { Button } from './ui/Button';

interface InternalToolTableProps {
  data: any[];
  onRowClick: (id: string) => void;
}

export const CompetitorInspiredTable: React.FC<InternalToolTableProps> = ({ data, onRowClick }) => {
  return (
    <div className="overflow-hidden rounded-lg border border-gray-200 shadow-sm">
      <table className="min-w-full divide-y divide-gray-200">
        <thead className="bg-gray-50">
          <tr>
            <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">User</th>
            <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">Status</th>
            <th className="px-6 py-3 text-right">Actions</th>
          </tr>
        </thead>
        <tbody className="bg-white divide-y divide-gray-200">
          {data.map((row) => (
            <tr key={row.id} onClick={() => onRowClick(row.id)} className="hover:bg-gray-50 cursor-pointer">
              <td className="px-6 py-4 whitespace-nowrap">{row.name}</td>
              <td className="px-6 py-4">
                <span className={`badge-${row.status}`}>{row.status}</span>
              </td>
              <td className="px-6 py-4 text-right">
                <Button variant="ghost">Edit</Button>
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
};

This code is ready for your Design System Sync. Replay ensures that the generated components use your specific brand tokens—colors, spacing, and typography—rather than the competitor's exact styling.

---

How can AI agents use Replay’s Headless API?#

The future of building first internal tool isn't just a human dev using a GUI. It’s AI agents like Devin or OpenHands doing the heavy lifting. Replay offers a Headless API (REST + Webhooks) that allows these agents to programmatically generate code from video.

Imagine an agent that monitors your competitors' product updates. When a competitor releases a new feature, the agent records the UI, sends it to Replay’s API, and submits a Pull Request to your internal tool repository with the updated UI logic. This is not science fiction; it is the current state of Visual Reverse Engineering.

bash
# Example API Call to Replay Headless API
curl -X POST "https://api.replay.build/v1/extract" \
     -H "Authorization: Bearer $REPLAY_API_KEY" \
     -F "video=@walkthrough.mp4" \
     -F "framework=react" \
     -F "styling=tailwind"

---

Can I build a full multi-page tool from one video?#

Yes. One of the biggest challenges in building first internal tool is mapping the navigation. Replay’s Flow Map feature detects temporal context. If a video shows a user clicking a sidebar link and the URL changes, Replay identifies this as a route transition.

It automatically generates the React Router or Next.js directory structure needed to support that multi-page flow. This prevents the "single page trap" where developers build a great dashboard but forget the settings page, the user profile, and the audit logs.

---

Why is modernizing legacy systems easier with Replay?#

Many companies are building first internal tool to replace a 20-year-old legacy system. These systems are often undocumented and written in languages like COBOL or old versions of Java.

Legacy modernization is the process of updating outdated software to modern architectures. Replay makes this painless by treating the legacy system as a "black box." You don't need to understand the backend code; you just need to record the user performing their daily tasks. Replay extracts the "Behavioral Logic" and recreates it in a modern React stack. This bypasses the $3.6 trillion global technical debt problem by focusing on the visible interface and user outcomes rather than the spaghetti code underneath.

---

How do I ensure the generated tool is production-ready?#

Building first internal tool is only half the battle. You also need to test it. Manual testing is a bottleneck that delays deployment. Replay solves this by offering E2E Test Generation.

When Replay analyzes your video, it doesn't just write React code; it writes Playwright or Cypress tests that mimic the actions taken in the video. This ensures that the code you ship actually works. If the video showed a user successfully submitting a form, your generated code will come with a test suite that verifies that specific form submission 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 uses advanced visual AI to extract components, design tokens, and navigation flows from screen recordings, making it the most efficient way to build internal tools and modernize legacy interfaces.

How do I modernize a legacy system without documentation?#

The most effective way is to use Replay's "Record → Extract → Modernize" workflow. By recording the legacy system in use, Replay can reverse engineer the UI and logic into modern React code, effectively bypassing the need for original source code or documentation.

Can Replay extract design tokens from Figma?#

Yes, Replay includes a Figma Plugin that allows you to extract design tokens directly from your design files. You can then sync these tokens with your video-to-code projects to ensure that the generated React components perfectly match your brand's design system.

Is Replay SOC2 and HIPAA compliant?#

Yes. Replay is built for enterprise and regulated environments. It offers SOC2 compliance, is HIPAA-ready, and provides On-Premise deployment options for companies with strict data residency and security requirements.

How much time does Replay save when building first internal tool?#

According to Replay's internal benchmarks, the platform reduces development time by 90%. A task that typically takes 40 hours of manual coding—such as building a complex data dashboard—can be completed in approximately 4 hours using Replay’s video-to-code engine.

---

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