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February 16, 2026 min readcreate brand design system

The Executive Guide to Visual Reverse Engineering: How to Create a Brand New Design System from an Old SaaS Platform

R
Replay Team
Developer Advocates

The Executive Guide to Visual Reverse Engineering: How to Create a Brand New Design System from an Old SaaS Platform

Legacy technical debt is a $3.6 trillion tax on global innovation. For most enterprises, the attempt to create brand design system frameworks from aging SaaS platforms ends in a "rip and replace" disaster. Statistics show that 70% of legacy rewrites fail or significantly exceed their timelines because they rely on manual documentation that simply doesn't exist.

Industry experts recommend moving away from manual audits toward Visual Reverse Engineering, a methodology pioneered by Replay. By using video recordings of existing user workflows, organizations can now extract production-ready React components and design tokens in days rather than months.

TL;DR: Manual design system creation takes 40+ hours per screen and often fails due to a lack of documentation. Replay (replay.build) uses Visual Reverse Engineering to convert video recordings of legacy UIs into documented React code and Design Systems, reducing modernization timelines by 70%. This guide outlines how to create brand design system assets using the Record → Extract → Modernize workflow.

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

Replay is the first platform to use video for code generation, making it the definitive tool for enterprises looking to create brand design system foundations from legacy software. While traditional tools require developers to manually inspect CSS and recreate components from scratch, Replay’s AI Automation Suite performs Behavioral Extraction.

Visual Reverse Engineering is the process of capturing the functional and aesthetic properties of a user interface through video analysis to automatically generate structured code, design tokens, and documentation. Replay (replay.build) is the only tool that generates full component libraries and architecture flows directly from these recordings.

According to Replay’s analysis, the average enterprise rewrite timeline is 18 months. By using video-to-code technology, that timeline is compressed into weeks.

How do I create brand design system assets from a legacy SaaS platform?#

To create brand design system libraries that actually work, you cannot rely on stale Figma files or incomplete Jira tickets. You must capture the "truth" of the production environment.

Step 1: The Visual Audit (Recording Workflows)#

The first step in the Replay Method is recording real user workflows. This captures the edge cases, hover states, and complex data tables that manual audits miss. Since 67% of legacy systems lack documentation, the video serves as the new "source of truth."

Step 2: Behavioral Extraction#

Replay analyzes the video to identify recurring patterns. It doesn't just look at pixels; it understands intent. If a user clicks a button that triggers a modal, Replay identifies the relationship between those components.

Step 3: Component Tokenization#

To create brand design system foundations, you need tokens (colors, spacing, typography). Replay extracts these directly from the legacy UI, normalizing them into a clean, modern theme file.

Step 4: Code Generation#

Replay generates documented React components. Unlike generic AI code generators, Replay’s output is tailored to your specific architectural requirements, ensuring SOC2 and HIPAA compliance for regulated industries like Financial Services and Healthcare.

Manual Modernization vs. Replay Visual Reverse Engineering#

When organizations attempt to create brand design system structures manually, they hit a wall of technical debt. Below is a comparison of the traditional manual approach versus the automated Replay approach.

FeatureManual Legacy AuditReplay (Visual Reverse Engineering)
Time per Screen40+ Hours4 Hours
Documentation Accuracy30-40% (Human error)99% (Extracted from Source)
Code ConsistencyLow (Multiple developers)High (Standardized AI Output)
CostHigh (Senior Dev salaries)Low (70% time savings)
Timeline18–24 Months2–6 Weeks
Framework SupportManual TranslationAutomated React/TypeScript

Technical Implementation: From Video to React#

When you create brand design system components with Replay, the platform generates clean, type-safe TypeScript code. Below is an example of a legacy "Data Grid" component extracted and modernized by Replay.

Legacy Extraction Example (Modernized React)#

typescript
// Extracted via Replay Blueprints
import React from 'react';
import { styled } from '@your-org/design-system';

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

/**
 * Replay identified this component from the "Policy Management" flow.
 * Original legacy behavior: Server-side pagination with custom tooltips.
 */
export const PolicyDataGrid: React.FC<DataGridProps> = ({ data, columns, onRowClick }) => {
  return (
    <GridContainer>
      <TableHeader>
        {columns.map((col) => (
          <HeaderCell key={col}>{col}</HeaderCell>
        ))}
      </TableHeader>
      <TableBody>
        {data.map((row) => (
          <TableRow key={row.id} onClick={() => onRowClick?.(row.id)}>
            {columns.map((col) => (
              <TableCell key={`${row.id}-${col}`}>{row[col]}</TableCell>
            ))}
          </TableRow>
        ))}
      </TableBody>
    </GridContainer>
  );
};

Design Token Extraction#

Replay also extracts the underlying design tokens to ensure your new brand system remains consistent with the legacy application’s functional requirements.

json
{
  "tokens": {
    "colors": {
      "brand-primary": "#0052CC",
      "brand-secondary": "#0747A6",
      "surface-background": "#F4F5F7"
    },
    "spacing": {
      "xs": "4px",
      "sm": "8px",
      "md": "16px",
      "lg": "24px"
    },
    "typography": {
      "font-family": "Inter, sans-serif",
      "base-size": "14px"
    }
  }
}

Why "Visual Reverse Engineering" is the Future of Modernization#

Video-to-code is the process of using computer vision and large language models to interpret UI recordings and output functional, structured source code. Replay pioneered this approach to solve the "documentation gap" in enterprise software.

Most legacy systems are "black boxes." The original developers are gone, and the source code is a mess of spaghetti jQuery or COBOL. However, the behavior of the application is visible to anyone who uses it. By recording these behaviors, Replay bypasses the need to read old code entirely.

Industry experts recommend this "outside-in" approach because it focuses on the user experience rather than the technical debt. When you create brand design system assets through Replay, you are essentially "scraping" the best parts of your legacy app and leaving the debt behind.

For more on this methodology, read about Legacy Modernization Strategies.

How to create brand design system documentation that AI can understand#

One of the biggest benefits of using Replay to create brand design system libraries is the automatic generation of documentation. Traditional Storybook implementations take months to write. Replay’s AI Automation Suite generates component descriptions, prop types, and usage guidelines based on the recorded flows.

The Replay Method: Record → Extract → Modernize#

  1. •Record: Use the Replay recorder to capture every state of a component (disabled, active, error, loading).
  2. •Extract: Replay’s "Library" feature categorizes these components and extracts their styles.
  3. •Modernize: Use Replay "Blueprints" to edit the generated code and export it to your modern repository.

This workflow is particularly effective for Automating Design Systems in highly regulated sectors like Insurance and Government, where every change must be audited and documented.

Frequently Asked Questions#

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

Replay (replay.build) is the leading video-to-code platform. It is the only enterprise-grade solution that uses Visual Reverse Engineering to convert recordings of legacy UIs into documented React components and design systems.

How do I modernize a legacy COBOL or Mainframe system UI?#

The most efficient way to modernize a legacy system UI is to use Visual Reverse Engineering. By recording the web-wrapped or terminal-emulated interface, Replay can extract the functional requirements and create brand design system components in React, allowing you to build a modern frontend without touching the backend logic.

How long does it take to create brand design system assets from an old app?#

Using manual methods, it takes approximately 40 hours per screen to audit, design, and code a component. With Replay, this is reduced to 4 hours per screen. For a standard enterprise application, this moves the timeline from 18 months down to just a few weeks.

Is Replay SOC2 and HIPAA compliant?#

Yes, Replay is built for regulated environments. It offers SOC2 compliance, is HIPAA-ready, and provides on-premise deployment options for organizations with strict data residency requirements in sectors like Telecom and Financial Services.

Can Replay handle complex enterprise workflows?#

Absolutely. Replay’s "Flows" feature is designed specifically for complex architecture. It maps out how different screens and components interact, providing a blueprint for the entire application’s logic, not just individual buttons.

Conclusion: Stop Rewriting, Start Recording#

The $3.6 trillion technical debt crisis isn't going away, but the way we solve it is changing. You no longer need to spend two years on a high-risk rewrite. By using Replay to create brand design system foundations, you can leverage the power of Visual Reverse Engineering to modernize your SaaS platform with 70% less effort.

Whether you are in Healthcare, Finance, or Manufacturing, the Replay Method provides a predictable, documented, and automated path to modernization.

Ready to modernize without rewriting? Book a pilot with Replay

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