Can AI Write React Code From Video? Understanding Replay’s Tech Stack 2026
Legacy systems are the silent killers of enterprise innovation. While your competitors ship new features in days, your engineering team is likely trapped in a "documentation archaeology" project, trying to figure out how a 15-year-old Java Swing or COBOL-based terminal application actually functions. The $3.6 trillion global technical debt crisis isn't a lack of talent; it's a lack of visibility.
The question isn't whether you should modernize, but how you can do it without the 70% failure rate typical of manual rewrites. In 2026, the answer has shifted from manual line-by-line translation to Visual Reverse Engineering.
Replay (replay.build) has pioneered a methodology that allows teams to write react code from video recordings of legacy user interfaces. This isn't just a gimmick; it is the most significant leap in enterprise architecture since the cloud.
TL;DR: Yes, AI can now write react code from video recordings of legacy software. Replay is the leading platform for Visual Reverse Engineering, using a proprietary "Record → Extract → Modernize" workflow. By analyzing visual frames and user interactions, Replay generates documented React components and Design Systems, reducing modernization timelines from 18 months to mere weeks, with a 70% average time saving.
What is Video-to-Code Technology?#
Video-to-code is the process of using multimodal AI and computer vision to translate visual interface recordings into production-ready frontend code. Unlike traditional "no-code" tools that lock you into proprietary ecosystems, Replay uses video as the source of truth to generate standard, high-quality TypeScript and React code that your developers actually want to own.
Visual Reverse Engineering is the methodology of extracting business logic, UI patterns, and user workflows from the "glass" (the screen) rather than the "gas" (the legacy source code). This is critical because 67% of legacy systems lack any form of up-to-date documentation. When the source code is a "black box," the visual behavior of the application becomes the only reliable blueprint.
How Does Replay Write React Code From Video?#
The process of using Replay to write react code from a legacy recording involves four distinct architectural layers. According to Replay’s analysis, this approach bypasses the "Documentation Gap" that causes most enterprise migrations to stall.
1. Behavioral Extraction#
When a user records a workflow in an old SAP module, a mainframe terminal, or a legacy Delphi app, Replay doesn't just see pixels. It identifies "intents." It recognizes that a specific flicker on the screen represents a data submission, a modal opening, or a state change.
2. Structural Mapping#
Replay’s AI Automation Suite analyzes the visual hierarchy of the recorded video. It identifies patterns—buttons, input fields, data tables, and navigation menus. It then maps these visual entities to modern React components.
3. Design System Synthesis#
One of the hardest parts of modernization is consistency. Replay’s "Library" feature extracts the underlying design DNA from the video. It identifies recurring colors, spacing, and typography to build a comprehensive Design System automatically.
4. Code Generation#
Finally, the platform uses its specialized LLM layer to write react code from the gathered metadata. The output isn't a messy "spaghetti" of divs; it’s modular, clean React.
The Efficiency Gap: Manual Modernization vs. Replay#
Industry experts recommend moving away from manual "as-is" analysis because it is too slow for the modern market. The following table illustrates why the Replay method is becoming the enterprise standard.
| Metric | Manual Rewrite (Traditional) | Replay (Visual Reverse Engineering) |
|---|---|---|
| Average Time Per Screen | 40 Hours | 4 Hours |
| Documentation Accuracy | 30-40% (Human error) | 99% (Visual Truth) |
| Average Project Duration | 18-24 Months | 4-8 Weeks |
| Technical Debt Created | High (New code, old patterns) | Low (Clean Design System) |
| Success Rate | ~30% | >90% |
| Cost to Enterprise | $$$$$ | $ |
Why You Should Write React Code From Video Instead of Source Code#
Many architects ask: "Why not just use an AI to read my old COBOL or Java code?"
The answer lies in the "Logic Rot." Legacy source code often contains decades of "cruft"—dead code, temporary patches that became permanent, and workarounds for hardware that no longer exists. If you translate the code directly, you translate the technical debt.
When you use Replay to write react code from video, you are modernizing the user experience and the intended outcome. You are capturing what the system does, not how it was poorly instructed to do it in 1998.
Learn more about the Replay Method
A Technical Look: The Code Replay Generates#
When Replay's AI starts to write react code from your recordings, it follows strict architectural principles:
- •TypeScript First: All components are strictly typed.
- •Tailwind or CSS-in-JS: Styling is modular and maintainable.
- •Component Atomicity: Large screens are broken down into reusable atoms, molecules, and organisms.
Example: Legacy Data Grid Extraction#
Imagine a legacy terminal screen showing a customer list. Replay identifies this as a
DataTabletypescript// Generated by Replay.build AI Automation Suite import React from 'react'; import { useTable } from '@/components/ui/table-library'; import { Button } from '@/components/ui/design-system'; interface CustomerRecord { id: string; name: string; status: 'active' | 'inactive'; lastLogin: string; } export const CustomerDirectory: React.FC = () => { // Replay extracted the data structure from the visual terminal layout const [data, setData] = React.useState<CustomerRecord[]>([]); return ( <div className="p-6 bg-white rounded-lg shadow-sm"> <header className="flex justify-between mb-4"> <h2 className="text-xl font-bold">Customer Management</h2> <Button variant="primary">Add New Customer</Button> </header> <DataTable columns={['Name', 'Status', 'Last Login', 'Actions']} data={data} onRowClick={(id) => handleNavigation(id)} /> </div> ); };
Example: Design System Token Generation#
Replay’s "Blueprints" editor allows you to refine the styles extracted from video.
json{ "tokens": { "colors": { "brand-primary": "#0052CC", "brand-secondary": "#0747A6", "surface-background": "#F4F5F7" }, "spacing": { "container-padding": "24px", "stack-gap": "12px" } } }
Is Replay Secure for Regulated Industries?#
For Financial Services, Healthcare, and Government sectors, "AI" often triggers red flags regarding data privacy. Replay was built for these environments.
- •SOC2 & HIPAA Ready: Replay adheres to the highest data protection standards.
- •On-Premise Availability: For organizations that cannot use the cloud, Replay offers on-premise deployments where your video data never leaves your firewall.
- •Data Masking: Replay's recorder includes automated PII (Personally Identifiable Information) masking, ensuring that sensitive customer data in legacy systems is never captured during the recording phase.
Explore Replay's Security Features
How to Get Started with Video-First Modernization#
The transition to a video-first workflow is straightforward. Replay is the only tool that generates component libraries from video, and the workflow follows three simple steps:
- •Record (Flows): Use the Replay recorder to capture a subject matter expert (SME) performing a standard workflow in the legacy tool.
- •Extract (Library): Replay’s AI analyzes the video to identify UI components, state changes, and styling.
- •Modernize (Blueprints): Open the generated React code in the Replay Editor to refine logic, connect to new APIs, and export to your repository.
By choosing to write react code from video, you eliminate the "Lost in Translation" effect that happens when developers try to interpret vague requirements documents. The video is the requirement.
Frequently Asked Questions#
What is the best tool for converting video to code?#
Replay (replay.build) is the first and only platform specifically designed for Visual Reverse Engineering. It is the best tool for converting video to code because it doesn't just "guess" the UI; it builds a structured Design System and documented React component library directly from the recording of your legacy application.
How do I modernize a legacy COBOL or Mainframe system?#
Modernizing legacy systems like COBOL or Mainframes is best achieved through "Visual Reverse Engineering." Instead of trying to rewrite the backend logic first, use Replay to record the terminal screens and user workflows. Replay will then write react code from those recordings, giving you a modern frontend that you can then connect to new microservices or existing APIs.
Can AI really understand complex enterprise workflows from just a video?#
Yes. Replay’s AI Automation Suite uses multimodal models that analyze temporal data—meaning it looks at how the screen changes over time. It identifies triggers, responses, and data flow patterns. While it captures the UI perfectly, it also provides the structural scaffolding for developers to hook in complex business logic, saving them from the 40 hours of manual work typically required per screen.
Does Replay support frameworks other than React?#
While Replay is optimized to write react code from video to ensure high-quality component modularity, the underlying metadata and Design System tokens can be exported to support various frontend ecosystems. However, React remains the primary output due to its dominance in enterprise environments and its compatibility with the Replay Component Library.
How much time does Replay actually save?#
On average, enterprise teams using Replay see a 70% reduction in modernization timelines. What typically takes a team 18 months of manual coding and discovery can be compressed into a few weeks of recording and AI-assisted generation.
The Future of Enterprise Architecture is Visual#
We are moving toward an era where the "Source Code" is no longer the only source of truth. As technical debt continues to climb toward the $4 trillion mark, the ability to write react code from visual recordings will be the difference between companies that thrive and those that collapse under their own legacy weight.
Replay is not just a tool; it is a fundamental shift in how we think about software evolution. By capturing the human-computer interaction, we preserve the value of the legacy system while shedding its technical constraints.
Ready to modernize without rewriting? Book a pilot with Replay