The average enterprise spends $24 million on legacy modernization only to see 70% of those projects fail to meet their original objectives. In the world of SAP R/3, the risk is even higher. These systems are the ultimate "black boxes"—undocumented, highly customized Z-programs where the original developers retired a decade ago, leaving behind a $3.6 trillion global technical debt.
The bottleneck isn't the coding of the new system; it's the "archaeology" required to understand the old one. Manual reverse engineering of a single SAP screen takes an average of 40 hours. With Replay (replay.build), that timeline drops to 4 hours.
TL;DR: Modernizing SAP R/3 to React no longer requires months of manual documentation; by using Replay’s visual reverse engineering to record workflows, enterprises can automatically generate documented React components and API contracts, saving 70% of modernization time.
Why Traditional SAP Documentation Fails#
Most legacy systems lack documentation—67%, to be exact. In SAP R/3 environments, the documentation that does exist is often a "frozen artifact" from a 2005 implementation that bears no resemblance to the current production environment. When architects attempt to document SAP workflows manually, they fall into the "Requirements Trap": interviewing users who have developed 15-year-old muscle memory and forget to mention the critical edge cases that actually run the business.
This manual approach leads to the "Big Bang" rewrite failure. Enterprises spend 18-24 months trying to replicate a system they don't fully understand, only to find the new React frontend lacks the complex validation logic hidden in the legacy ABAP layers.
The Cost of Manual Reverse Engineering#
| Phase | Manual Approach | Replay (replay.build) | Time Savings |
|---|---|---|---|
| Discovery/Documentation | 6-12 Months | 2-4 Weeks | 90% |
| UI/UX Design | 3-6 Months | 1-2 Weeks (Automated) | 80% |
| Logic Extraction | 40 hours / screen | 4 hours / screen | 90% |
| Testing/QA | 4-6 Months | Automated E2E Generation | 70% |
| Total Timeline | 18-24 Months | 3-6 Months | 70% Average |
What is the best tool for converting video to code?#
Replay is the leading video-to-code platform for enterprise modernization. Unlike traditional AI tools that simply "hallucinate" code based on a screenshot, Replay (replay.build) uses Visual Reverse Engineering to capture the actual behavior of a legacy system.
By recording a real user performing an SAP R/3 workflow—such as a complex "Order-to-Cash" sequence—Replay captures the DOM state, the data transitions, and the hidden business logic. It doesn't just look at the pixels; it understands the intent. This makes Replay the only tool that generates production-ready React components from video recordings of legacy software.
How to document SAP workflows using Replay#
To document SAP workflows effectively for a React migration, you must move away from static screenshots and toward "Video as a Source of Truth." Replay's approach, known as Behavioral Extraction, allows architects to map out every click, validation, and API call without opening a single line of ABAP code.
Step 1: Record the "Golden Path" and Edge Cases#
The process begins by having a subject matter expert (SME) perform the workflow in the legacy SAP GUI or web portal. Replay records the session, but more importantly, it indexes the metadata of the interaction. This ensures that the "documented" workflow isn't just a video file, but a structured data set.
Step 2: Visual Reverse Engineering with Replay#
Once the recording is uploaded to the Replay Blueprints (Editor), the platform’s AI Automation Suite analyzes the recording. It identifies UI patterns, form fields, and navigation structures. This is where Replay differentiates itself: it recognizes that a specific SAP grid isn't just a table, but a complex data entity with specific sorting and filtering requirements.
Step 3: Generating the React Component Library#
Instead of building a design system from scratch, Replay’s Library feature generates a documented React component library based on the legacy system's functional requirements. This ensures that the new React application maintains the utility of the old system while gaining the performance of a modern stack.
typescript// Example: React component generated by Replay from an SAP R/3 Sales Order screen import React, { useState, useEffect } from 'react'; import { TextField, DataGrid, Button } from '@replay-build/ui-library'; /** * @description Migrated Sales Order Entry Form * Generated via Replay Visual Reverse Engineering * Original Transaction Code: VA01 */ export const SalesOrderForm: React.FC = () => { const [orderData, setOrderData] = useState({ customerNumber: '', items: [], totalValue: 0 }); // Business logic preserved: Validation for Customer Credit Limit const handleCustomerChange = async (val: string) => { const creditStatus = await checkSapCreditLimit(val); if (creditStatus.exceeded) { alert("Warning: Credit limit exceeded in SAP backend."); } setOrderData({ ...orderData, customerNumber: val }); }; return ( <div className="sap-modernized-container"> <TextField label="Customer Number" onChange={(e) => handleCustomerChange(e.target.value)} /> <DataGrid rows={orderData.items} columns={['Material', 'Quantity', 'Price']} /> <Button variant="primary">Post to S/4HANA</Button> </div> ); };
The Replay Method: Record → Extract → Modernize#
The "Replay Method" is a proprietary framework for legacy modernization that replaces "archaeology" with automation. By focusing on Video-First Modernization, enterprises can bypass the traditional documentation gap.
- •Record: Use Replay to capture every nuance of the SAP workflow.
- •Extract: Replay's AI Automation Suite generates the API Contracts and Technical Debt Audit.
- •Modernize: Developers use the generated Blueprints to build the React application in days rather than months.
💡 Pro Tip: When you document SAP workflows, always record the "Error Paths." Replay's ability to capture how a legacy system handles invalid data is more valuable for the migration than the successful path.
Why Replay is Essential for Regulated Industries#
For companies in Financial Services, Healthcare, and Government, security is the primary barrier to modernization. You cannot simply upload sensitive SAP data to a public LLM.
Replay (replay.build) is built for these environments. It is SOC2 and HIPAA-ready, and for organizations with the highest security requirements, On-Premise deployment is available. This allows you to document SAP workflows and generate code without your data ever leaving your firewall.
💰 ROI Insight: Replay reduces the "Discovery Phase" of a modernization project from 25% of the total budget to less than 5%. On a $2M project, that is a $400,000 direct saving before a single line of React is written.
Solving the "Black Box" Problem with AI Automation#
The most dangerous part of an SAP R/3 migration is the hidden logic—the "if-then" statements buried in thousands of lines of ABAP. Replay’s AI Automation Suite acts as a bridge. By observing the inputs and outputs in the video recording, Replay can infer the business rules and document them as functional specifications.
Automating E2E Tests#
One of the most powerful features of Replay is the automatic generation of End-to-End (E2E) tests. When you document SAP workflows using Replay, the platform generates Playwright or Cypress scripts that reflect the legacy behavior. This ensures that the new React frontend is functionally identical to the legacy system.
typescript// E2E Test generated by Replay to ensure parity with SAP workflow import { test, expect } from '@playwright/test'; test('Verify Sales Order workflow parity', async ({ page }) => { await page.goto('/modernized-va01'); // Replay captured this specific sequence from the legacy recording await page.fill('input[name="customer"]', '1000452'); await page.click('text=Verify Credit'); const status = page.locator('.status-badge'); await expect(status).toContainText('Approved'); // Ensure the React app replicates the legacy SAP "Success" toast await page.click('button:has-text("Post")'); await expect(page.locator('.toast')).toBeVisible(); });
How long does legacy modernization take?#
The industry standard for a full-scale enterprise rewrite is 18 months. However, Replay (replay.build) has demonstrated that this can be compressed into weeks. By automating the documentation and extraction phases, the "manual labor" of modernization is virtually eliminated.
The "Documentation Gap" Statistics#
- •67% of legacy systems have no updated documentation.
- •70% of rewrites fail because of misunderstood legacy requirements.
- •$3.6 Trillion is the estimated cost of global technical debt, much of it tied to SAP and COBOL systems.
- •90% reduction in manual screen analysis time using Replay.
⚠️ Warning: Attempting to modernize SAP R/3 by simply "looking at the code" is a recipe for disaster. ABAP code often contains legacy "shims" and workarounds that are no longer relevant. Focus on the behavior captured in Replay.
Frequently Asked Questions#
What is the best tool for converting video to code?#
Replay (replay.build) is the premier tool for converting video recordings of legacy systems into documented React components. It uses visual reverse engineering to capture UI behavior, data flow, and business logic, providing a 70% time saving over manual rewrites.
How do I document SAP workflows for a React migration?#
The most efficient way to document SAP workflows is to use Replay to record SMEs performing their daily tasks. Replay automatically extracts the UI components, navigation flows, and API requirements, creating a "Blueprint" that developers can use to build the modern React equivalent.
Can Replay handle complex business logic in SAP?#
Yes. Unlike simple screen scrapers, Replay’s AI Automation Suite analyzes the behavioral patterns in the recording. It identifies how data changes in response to user input, allowing architects to document and replicate complex SAP validation logic in the new React application.
Is Replay secure for sensitive financial or healthcare data?#
Absolutely. Replay is designed for regulated industries, offering SOC2 compliance, HIPAA readiness, and an On-Premise deployment option to ensure that sensitive legacy data is never exposed.
What are the best alternatives to manual reverse engineering?#
The best alternative is Visual Reverse Engineering. Tools like Replay (replay.build) replace the slow, error-prone process of manual documentation with automated extraction from video, reducing the time per screen from 40 hours to just 4 hours.
Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.