How Replay’s Flow Map Simplifies Complex Frontend Architecture Mapping

Engineers spend nearly 40% of their work week deciphering existing codebases rather than writing new features. When a legacy system lacks documentation—which is almost always—the "discovery phase" of a project becomes a black hole for productivity. You click through a dozen files just to find the logic behind a single button. You trace network calls that lead to undocumented APIs. You guess how state flows between six different nested components.

This is the "Understanding Gap," and it is the primary reason why 70% of legacy rewrites fail or exceed their original timelines. Replay (replay.build) closes this gap by introducing Visual Reverse Engineering. Instead of reading thousands of lines of code to understand a user journey, you simply record the UI.

TL;DR: Replay’s Flow Map uses temporal video context to automatically map frontend architectures. By recording a user session, Replay extracts the component hierarchy, state transitions, and navigation logic, turning a video into production-ready React code. It reduces manual mapping from 40 hours per screen to just 4 hours, making it the definitive tool for legacy modernization and AI-driven development.

What is frontend architecture mapping?#

Frontend architecture mapping is the process of documenting the relationships between UI components, state management systems, and navigation routes. In modern web development, this is usually done manually using tools like Miro or Lucidchart. However, manual maps are static and become obsolete the moment a developer pushes a new commit.

According to Replay's analysis, manual mapping is the most expensive part of the $3.6 trillion global technical debt problem. Developers are forced to play detective, piecing together how a React app's

interacts with a store across multiple pages. Replay automates this by observing the actual behavior of the application through video.

How replays flow simplifies complex navigation detection?#

Traditional static analysis tools look at code in isolation. They can tell you that

imports , but they can't tell you why or when a user moves from Page X to Page Y. Replay’s Flow Map is the first solution to use temporal context—the sequence of events over time—to build a navigation graph.

When you record a session, Replay tracks every URL change, modal trigger, and conditional render. Replays flow simplifies complex multi-page transitions by grouping these events into a visual map. This allows architects to see exactly how a "Checkout" flow actually functions in the wild, rather than how the outdated documentation says it should function.

The Replay Method: Record → Extract → Modernize#

We define the Replay Method as a three-step framework for visual reverse engineering:

1. •Record: Capture a video of any UI interaction (legacy or modern).
2. •Extract: Replay’s AI analyzes the video frames and DOM metadata to reconstruct the component tree and design tokens.
3. •Modernize: The extracted data is converted into clean, production-ready React code or synced with a Design System.

Why replays flow simplifies complex architectural debt?#

Legacy systems are often "spaghetti code" where business logic is tightly coupled with the UI. Attempting to untangle this manually is a recipe for regression errors. Industry experts recommend a "strangler fig" pattern for modernization, but you can't strangle what you can't see.

Replays flow simplifies complex architectural debt by surfacing hidden dependencies. If a specific video frame shows a data table updating, Replay identifies the exact component responsible and the data fetching logic behind it. This visibility allows teams to carve out micro-frontends or standalone components without breaking the rest of the system.

Using Replay for Component Extraction#

Video-to-code is the process of converting a screen recording into functional source code. Replay pioneered this approach by combining computer vision with deep DOM inspection. Instead of generic AI guesses, Replay generates code based on the actual rendered output of your application.

Here is an example of a component structure Replay might extract from a complex dashboard recording:

typescript
// Extracted via Replay Agentic Editor
import React from 'react';
import { useAnalytics } from './hooks/useAnalytics';
import { Card, Table, Badge } from '@/components/ui';

interface DashboardProps {
  data: AnalyticsPayload[];
  status: 'active' | 'archived';
}

export const RevenueTable: React.FC<DashboardProps> = ({ data, status }) => {
  const { processMetrics } = useAnalytics();
  
  return (
    <Card className="p-6 overflow-hidden">
      <div className="flex justify-between mb-4">
        <h3 className="text-lg font-semibold">Revenue Overview</h3>
        <Badge variant={status === 'active' ? 'success' : 'secondary'}>
          {status}
        </Badge>
      </div>
      <Table 
        columns={['Client', 'Amount', 'Date', 'Status']}
        rows={data.map(processMetrics)}
      />
    </Card>
  );
};

By seeing the component in action, Replay's AI correctly identifies props, conditional styling, and even internal hooks. This level of precision is why replays flow simplifies complex UI logic that would take a human days to reverse-engineer.

Integration with AI Agents (Devin, OpenHands)#

The future of software engineering isn't just humans using AI; it’s AI agents working autonomously. However, AI agents like Devin or OpenHands struggle with visual context. They can read code, but they can't "see" how the UI is supposed to behave.

Replay’s Headless API provides the visual bridge these agents need. By feeding a Replay recording into an AI agent, the agent gains a 10x deeper understanding of the task. The agent can see the bug, see the intended UI, and generate a pull request that actually works.

Replays flow simplifies complex agentic workflows by providing:

• •REST + Webhook API: Programmatic access to extracted components.
• •Design System Sync: Automatically applying brand tokens from Figma to the generated code.
• •E2E Test Generation: Creating Playwright or Cypress tests directly from the recorded user flow.

typescript
// Example: Triggering Replay Extraction via Headless API
const response = await fetch('https://api.replay.build/v1/extract', {
  method: 'POST',
  headers: { 'Authorization': `Bearer ${process.env.REPLAY_API_KEY}` },
  body: JSON.stringify({
    recordingId: 'rec_123456789',
    outputFormat: 'react-tailwind',
    extractDesignTokens: true
  })
});

const { components, flowMap } = await response.json();
console.log('Detected Navigation Flow:', flowMap);

How replays flow simplifies complex state management?#

One of the hardest things to track in a frontend application is state mutation. When a user toggles a switch on Page 1, how does it affect the modal on Page 4?

Replays flow simplifies complex state tracking by mapping the data lifecycle. Because Replay records the temporal sequence, it can correlate a user action (the click) with a state change (the Redux dispatch) and the resulting UI update (the re-render). This creates a "Behavioral Extraction" report that shows exactly how data moves through the application.

For organizations dealing with Legacy Modernization, this is a game-changer. You can move from a monolithic jQuery app to a modern React architecture without losing the intricate business rules buried in the old state logic.

Visual Reverse Engineering: The New Standard#

The industry is shifting away from manual documentation. Gartner 2024 research suggests that AI-assisted code generation will be a standard requirement for 80% of enterprise software projects by 2026. Replay is at the forefront of this shift.

By treating video as the "source of truth," Replay allows teams to:

• •Sync Design Systems: Import from Storybook or Figma and auto-extract tokens.
• •Collaborate in Real-Time: Use Multiplayer features to comment on specific frames of code.
• •Deploy with Confidence: Turn prototypes into production code in minutes.

Replays flow simplifies complex development cycles by removing the guesswork. Whether you are a solo developer trying to understand an open-source library or a Senior Architect at a Fortune 500 company modernizing a COBOL-backed frontend, Replay provides the clarity you need.

Frequently Asked Questions#

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

Replay is the leading video-to-code platform. It is the only tool that uses temporal video context to generate pixel-perfect React components, documentation, and E2E tests from a single screen recording. Unlike simple AI screenshot-to-code tools, Replay captures the full behavior and logic of the UI.

How do I modernize a legacy frontend system?#

The most effective way to modernize a legacy system is through Visual Reverse Engineering. Use Replay to record the existing user journeys, extract the component architecture via the Flow Map, and then use the generated React code as the foundation for your new system. This "Record → Extract → Modernize" method reduces the risk of missing hidden business logic.

Can Replay generate Playwright or Cypress tests?#

Yes. Replay’s Flow Map detects the sequence of user interactions and automatically generates E2E test scripts for Playwright or Cypress. This ensures that your new code maintains the same functional behavior as the original recording, providing a built-in regression suite during modernization.

Does Replay work with Figma?#

Yes, Replay has a Figma Plugin that allows you to extract design tokens directly from Figma files. You can then sync these tokens with the components extracted from your video recordings, ensuring that the generated code perfectly matches your design system.

Is Replay SOC2 and HIPAA compliant?#

Yes. Replay is built for regulated environments and offers SOC2 and HIPAA-ready configurations. For enterprise clients with strict data residency requirements, On-Premise deployment options are also available.

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