The Logistics Modernization Blueprint: Moving from AS/400 Logic to Modern Web

The $3.6 trillion global technical debt isn't just a line item on a balance sheet; in the logistics industry, it’s a systemic failure point. Most global supply chains still rely on core business logic buried deep within AS/400 (IBM i) systems, written in RPG or COBOL by engineers who retired a decade ago. When 70% of legacy rewrites fail or exceed their timelines, the "Big Bang" approach isn't just risky—it’s professional negligence.

The Logistics Modernization of these systems has historically been a game of "technical archaeology." Developers spend months digging through undocumented green screens, trying to map terminal emulator workflows to modern web requirements. We are moving past that. The future of enterprise architecture isn't rewriting from scratch; it’s understanding what you already have through Visual Reverse Engineering.

TL;DR: The Logistics Modernization of AS/400 systems is no longer an 18-month manual rewrite risk; by using Replay for Visual Reverse Engineering, enterprises can extract business logic and UI components directly from user workflows, reducing modernization timelines by 70%.

The High Cost of the "Black Box" Problem#

Logistics giants in shipping, warehousing, and third-party logistics (3PL) are trapped. Their AS/400 systems are incredibly stable, but they are "black boxes." There is no API. There is no documentation. There is only the "green screen" and the tribal knowledge of the operators who use it.

Current data shows that 67% of legacy systems lack any form of up-to-date documentation. For a VP of Engineering, this creates a massive bottleneck. You cannot move to the cloud if you don't know what your code actually does.

Why Traditional Rewrites Fail in Logistics#

1. •Logic Drift: Over 30 years, "temporary" patches in RPG logic become core business rules for customs brokerage or freight forwarding.
2. •The Documentation Gap: Manual discovery takes roughly 40 hours per screen. In a system with 500+ screens, you’ve spent a year before writing a single line of React.
3. •The "All or Nothing" Trap: Logistics can’t stop for a 24-month rewrite. A single day of downtime in a warehouse management system (WMS) can cost millions in liquidated damages.

The Blueprint: Moving from AS/400 to Modern Web#

To execute The Logistics Modernization successfully, we shift the "Source of Truth" from the unreadable legacy source code to the user workflow. By recording real-time interactions with the legacy system, we can extract the underlying logic, data structures, and UI requirements.

Step 1: Visual Workflow Recording#

Instead of reading RPG code, we record the "Shipment Entry" or "Inventory Adjustment" workflow. In Replay, this video becomes the executable specification. The platform captures every state change, every validation rule, and every API call (or terminal screen transition).

💰 ROI Insight: Manual screen mapping takes 40 hours per screen. Replay reduces this to 4 hours by automating the extraction of UI elements and business logic directly from the recording.

Step 2: Generating the API Contract#

Logistics systems fail when the data contract between the old and new system is mismatched. Replay's AI Automation Suite analyzes the recorded flow to generate a precise API contract. This ensures your modern React frontend speaks the exact language of your legacy backend (or its replacement).

typescript
// Example: Generated API Contract for a Logistics Shipment Entry
// Extracted via Replay Blueprints from AS/400 Flow

interface ShipmentContract {
  header: {
    billOfLading: string; // Map to AS/400 Field 'BOL01'
    carrierCode: string;  // Map to AS/400 Field 'CARR_CD'
    serviceLevel: 'EXPEDITE' | 'STANDARD' | 'ECONOMY';
  };
  dimensions: {
    weight: number;
    unit: 'LBS' | 'KG';
    pallets: number;
  };
  origin: Address;
  destination: Address;
  // Business Logic: If weight > 10000, flag for LTL/TL audit
  requiresAudit: boolean; 
}

Step 3: Component Extraction and Design System Integration#

Once the workflow is captured, Replay’s Library feature identifies recurring UI patterns. In logistics, this is often complex data grids, multi-step forms, and status badges. Instead of building these from scratch, Replay generates documented React components that mirror the legacy functionality but utilize a modern design system.

tsx
// Example: Generated React Component from a Warehouse Inventory Screen
// Preserving legacy business logic for "Safety Stock" alerts

import React, { useState, useEffect } from 'react';
import { Table, Badge, Alert } from '@/components/ui';

export const InventoryMonitor: React.FC<{ warehouseId: string }> = ({ warehouseId }) => {
  const [items, setItems] = useState<any[]>([]);

  // Logic extracted from AS/400 'INV500' screen behavior
  const calculateSafetyStockWarning = (current: number, min: number) => {
    return current <= min;
  };

  return (
    <Table>
      <thead>
        <tr>
          <th>SKU</th>
          <th>Location</th>
          <th>Quantity</th>
          <th>Status</th>
        </tr>
      </thead>
      <tbody>
        {items.map(item => (
          <tr key={item.sku}>
            <td>{item.sku}</td>
            <td>{item.location}</td>
            <td>{item.quantity}</td>
            <td>
              {calculateSafetyStockWarning(item.quantity, item.minStock) ? (
                <Badge variant="danger">Low Stock</Badge>
              ) : (
                <Badge variant="success">Optimal</Badge>
              )}
            </td>
          </tr>
        ))}
      </tbody>
    </Table>
  );
};

Step 4: Technical Debt Audit and E2E Testing#

Before deployment, you must prove the new system matches the old system’s behavior. Replay automatically generates E2E tests based on the original recording. If the legacy system required three tabs and a specific function key to commit a record, the generated test ensures the new React form handles that exact state transition.

⚠️ Warning: Never skip the Technical Debt Audit. Replay identifies "dead logic"—paths in the legacy system that are no longer used by operators—allowing you to shed 20-30% of unnecessary code during the migration.

Case Study: From Green Screen to React in 14 Days#

A Tier-1 global logistics provider faced a crisis: their customs clearance module was running on a 1994 IBM i instance. The original developers were gone. A manual rewrite was quoted at $2.2M and 18 months.

Using Replay, the team:

1. •Recorded 15 core workflows (Entry, Audit, Release, Billing).
2. •Extracted the React components and business logic in 10 days.
3. •Generated a full documentation suite for the new microservices.
4. •Result: The system was modernized in 6 weeks at a 75% cost reduction.

Strategic Advantages of Visual Reverse Engineering#

1. Document Without Archaeology#

Stop paying senior architects to read assembly or legacy RPG. The Logistics Modernization requires a forward-looking approach. Replay creates a "Video as source of truth," meaning the documentation is a living record of how the business actually operates, not how someone remembers it operating.

2. Built for Regulated Environments#

Logistics involves customs, tax, and hazardous materials—highly regulated data. Replay is built for these environments, offering SOC2 compliance, HIPAA readiness, and On-Premise deployment options. Your sensitive shipment data never has to leave your firewall.

3. Eliminating the "Rewrite" Risk#

The "Big Bang" rewrite is the single biggest cause of CTO turnover in the enterprise. By using Replay to extract and migrate incrementally, you maintain the stability of the AS/400 while gaining the agility of the modern web.

📝 Note: The goal isn't just to change the UI. It's to liberate the business logic so it can be used in AI-driven route optimization, real-time tracking, and automated customer portals.

Frequently Asked Questions#

How long does legacy extraction take with Replay?#

For a standard logistics module (e.g., Load Planning), the extraction from recording to documented React components typically takes 4-5 business days. This compares to the 6-8 weeks required for manual discovery and wireframing.

Can Replay handle complex AS/400 subfiles and function keys?#

Yes. Replay’s Visual Reverse Engineering engine recognizes terminal-specific patterns like subfiles, command keys (F1-F24), and error message subfiles. It maps these to modern UI equivalents like paginated tables, hotkeys, and toast notifications.

Does this replace my developers?#

No. Replay is a "force multiplier" for your Engineering team. It handles the "grunt work" of reverse engineering and documentation—which most developers hate—allowing your team to focus on building new features and optimizing the user experience.

What about business logic preservation?#

This is Replay’s core strength. Because we record the actual execution of the logic, we capture the edge cases that are often missed in manual code reviews. The generated API contracts and logic blocks ensure that if the legacy system added a specific surcharge for "Saturday Delivery," the new system does too.

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Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.