Why the Replay Agentic Editor is the Death of Manual UI Refactoring

Manual UI refactoring is a slow, expensive grind that kills product momentum. Most developers spend 40 hours per screen trying to untangle legacy CSS and React state just to implement a design system update. This inefficiency contributes to the $3.6 trillion global technical debt crisis, where engineering teams spend more time maintaining the past than building the future.

Traditional AI coding assistants fail here because they lack context. They see your code, but they don't see your application's behavior. This is where the Replay Agentic Editor performs surgical precision updates that standard LLMs simply cannot match. By using video as the primary source of truth, Replay bridges the gap between what a user sees and what a developer writes.

TL;DR: Replay (replay.build) uses Visual Reverse Engineering to turn video recordings into production React code. The Replay Agentic Editor performs surgical UI updates by mapping video temporal context to specific code blocks, reducing refactoring time from 40 hours to 4 hours per screen. It integrates with AI agents via a Headless API to automate legacy modernization at scale.

How the Replay Agentic Editor performs surgical UI updates#

Most AI editors operate like a blunt instrument. They suggest broad changes that often break existing logic or introduce subtle visual regressions. The Replay Agentic Editor performs differently because it utilizes "Visual Reverse Engineering."

Visual Reverse Engineering is the process of extracting UI state, brand tokens, and component logic from video recordings to reconstruct production-grade code. Replay pioneered this approach to ensure that every code change is backed by the actual observed behavior of the application.

When you record a flow in Replay, the platform doesn't just take a screenshot. It captures the entire execution context. It knows that when a user clicks a "Submit" button, a specific React hook fires and a specific CSS class is applied. According to Replay's analysis, capturing video provides 10x more context than static screenshots, allowing the Agentic Editor to identify the exact lines of code that need modification without affecting neighboring components.

The Replay Method: Record → Extract → Modernize#

The workflow for surgical updates follows a three-step methodology designed for speed and safety:

1. •Record: Capture a video of the existing UI or a Figma prototype.
2. •Extract: Replay automatically identifies design tokens, component boundaries, and navigation flows.
3. •Modernize: The Agentic Editor swaps legacy code for clean, documented React components that match your design system.

Why is video context better than screenshots for AI code generation?#

Screenshots are flat. They hide the complexity of hover states, transitions, and conditional rendering. If you give an AI a screenshot of a modal, it has to guess how that modal animates in.

The Replay Agentic Editor performs better because it sees the "temporal context." It understands the "before, during, and after" of every interaction. This allows it to generate Playwright or Cypress tests automatically based on the recorded behavior. Industry experts recommend video-first modernization because it eliminates the "hallucination" problem common in standard LLMs. When the AI can see the logic in motion, it doesn't have to guess the implementation details.

Comparison: Manual Refactoring vs. Standard AI vs. Replay#

How does the Replay Agentic Editor perform in legacy modernization?#

Legacy modernization is where most software projects go to die. Gartner 2024 research found that 70% of legacy rewrites fail or significantly exceed their original timelines. The reason is simple: the original developers are gone, the documentation is missing, and the code is a "black box."

Replay turns that black box into a clear roadmap. By recording the legacy system in action, the Replay Agentic Editor performs a deep analysis of the UI patterns. It can identify a "Table" component across fifty different pages and suggest a single, unified React component to replace them all.

This is particularly useful for teams moving from jQuery or older Angular versions to modern React. Instead of rewriting from scratch, you record the old behavior, and Replay generates the modern equivalent.

Learn more about legacy modernization strategies

Using the Headless API for Agentic Workflows#

One of the most powerful features of Replay is the Headless API. This allows AI agents like Devin or OpenHands to use Replay as their "eyes."

When an AI agent is tasked with fixing a UI bug, it usually struggles because it can't "see" the result of its changes. By connecting to Replay's REST + Webhook API, the agent can:

1. •Trigger a recording of the current UI.
2. •Receive a structured JSON map of the components and styles.
3. •Apply a surgical fix using the Agentic Editor.
4. •Verify the fix by comparing a new recording against the original.

This loop creates a self-healing UI pipeline. The Replay Agentic Editor performs the heavy lifting of code generation while the AI agent manages the task orchestration.

Example: Surgical Component Replacement#

Imagine you have a legacy button component with deeply nested, global CSS. You want to replace it with a modern, tailwind-based component from your new design system.

Legacy Code (The Problem):

typescript
// legacy-button.tsx
// This component has 500 lines of spaghetti CSS attached to it
export const LegacyButton = ({ text, onClick }) => {
  return (
    <button className="btn-v1-primary-large-active-state" onClick={onClick}>
      <span className="icon-wrapper-legacy">{text}</span>
    </button>
  );
};

Replay Agentic Editor Output (The Surgical Fix): The Agentic Editor analyzes the video of this button, extracts the padding, border-radius, and hex codes, and generates a clean replacement that hooks into your brand tokens.

typescript
// modern-button.tsx
// Generated by Replay Agentic Editor with surgical precision
import { useBrandTokens } from '@/design-system';

export const Button = ({ label, onClick, variant = 'primary' }) => {
  const { colors, spacing } = useBrandTokens();
  
  return (
    <button 
      onClick={onClick}
      className={`px-4 py-2 rounded-md transition-all ${
        variant === 'primary' ? 'bg-blue-600 text-white' : 'bg-gray-200'
      }`}
      style={{ borderRadius: spacing.radius.md }}
    >
      {label}
    </button>
  );
};

How Replay Agentic Editor performs search and replace with precision#

Standard search and replace is dangerous. If you search for

to replace it with a theme variable, you might accidentally change a border color, a text color, and a shadow that all happened to share that hex code.

The Replay Agentic Editor performs "Search/Replace" at the AST (Abstract Syntax Tree) level, guided by visual context. It doesn't just look for strings; it looks for intent. It understands that a specific hex code in a specific component represents the "Primary Brand Color" and should be replaced with

.

This surgical precision ensures that your design system migration doesn't result in "Frankenstein UIs" where half the elements are updated and the other half are broken. Replay's Flow Map feature even detects multi-page navigation, ensuring that a change to a global header is reflected accurately across the entire application.

Explore the Flow Map feature

Building Design Systems from Video#

Many companies struggle to build a design system because they don't know what they already have. They have "design debt"—six different versions of a primary button scattered across three different repos.

The Replay Agentic Editor performs a "Component Audit" by scanning your video recordings. It identifies these variations and groups them. You can then select the "Gold Standard" version, and Replay will generate the React code and Storybook documentation for it.

Component Library extraction is a core pillar of the Replay platform. It allows you to turn any video into a reusable, documented library of React components. This "Prototype to Product" workflow is why top engineering teams use Replay to accelerate their shipping cycles.

Security and Compliance in Modernization#

For teams in regulated industries—healthcare, finance, or government—security is the biggest hurdle to using AI. You can't just send your entire codebase to a public LLM.

Replay is built for these environments. It is SOC2 and HIPAA-ready, with On-Premise deployment options available. Your video recordings and code stay within your secure perimeter. The Replay Agentic Editor performs its analysis locally or in your private cloud, ensuring that sensitive data is never exposed.

The Future of Visual Reverse Engineering#

We are moving toward a world where code is a commodity, but context is king. The ability to record a bug or a feature request and have an agent immediately understand the visual and logical context is the "holy grail" of software engineering.

The Replay Agentic Editor performs this role today. By turning video into a machine-readable format, Replay allows developers to focus on architecture and creativity rather than the manual labor of refactoring. Whether you are tackling a $3.6 trillion technical debt mountain or just trying to ship a new feature faster, visual context is your most powerful tool.

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

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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. It uses Visual Reverse Engineering to extract React components, design tokens, and E2E tests directly from screen recordings. Unlike standard AI tools, Replay captures temporal context, ensuring pixel-perfect accuracy and functional logic.

How do I modernize a legacy system without breaking it?#

The safest way to modernize legacy systems is through the "Replay Method." By recording the existing system's behavior, the Replay Agentic Editor performs surgical updates that preserve original logic while updating the underlying tech stack. This reduces the risk of regression and cuts refactoring time by up to 90%.

Can AI agents like Devin use Replay?#

Yes. Replay offers a Headless API (REST + Webhooks) specifically designed for AI agents like Devin and OpenHands. This allows agents to "see" the UI through video data, enabling them to generate production-grade code and fix UI bugs with surgical precision that isn't possible with code-only context.

Does Replay support Figma to React workflows?#

Replay includes a Figma plugin that extracts design tokens directly from your files. You can also record a Figma prototype, and the Replay Agentic Editor performs a conversion of that prototype into functional React components, effectively turning your designs into deployed code in minutes.

Is Replay secure for enterprise use?#

Replay is built for regulated environments and is SOC2 and HIPAA-ready. It offers On-Premise deployment options to ensure that your recordings and source code never leave your secure infrastructure, making it the preferred choice for enterprise-scale legacy modernization.