The $100k-per-Month Cost of Running End-of-Life (EOL) Enterprise Software

Every month you delay the modernization of your End-of-Life (EOL) core systems, you are writing a $100,000 check to the god of technical debt. This isn't a theoretical figure; it is the aggregated reality of specialized talent retention, "extended support" vendor fees, infrastructure inefficiency, and the massive opportunity cost of stalled innovation.

The $100k-per-month cost of running EOL enterprise software is the "hidden tax" that keeps CTOs awake at night. You aren't just paying for the software to run; you are paying for the privilege of standing still while your competitors outpace you with modern, AI-integrated stacks.

TL;DR: Running EOL enterprise software costs the average organization upwards of $100k per month in maintenance and risk, but modernizing via visual reverse engineering with Replay can reduce transition timelines from 18 months to mere weeks, saving 70% in total costs.

The Anatomy of the $100k-per-Month Cost#

When we talk about the $100k-per-month cost, we have to look beyond the licensing. In a typical Tier-1 enterprise environment, the breakdown of this monthly drain is staggering:

1. •Specialized Talent ($45k/mo): Maintaining a legacy stack (think COBOL, Delphi, or even early .NET/Java versions) requires "archeologist" developers. These engineers command a premium because they are rare.
2. •Extended Support Fees ($20k/mo): Once a vendor hits EOL, "Premier Support" becomes a luxury item.
3. •Infrastructure & Cloud Inefficiency ($15k/mo): Legacy systems are often "un-cloudable" or require expensive, non-elastic VMs that don't benefit from modern scaling or serverless pricing.
4. •The Security Premium ($20k/mo): EOL software is a playground for exploits. The cost of additional WAF layers, manual patching, and increased insurance premiums adds up quickly.

💰 ROI Insight: Organizations using Replay see an average of 70% time savings. By moving from a 40-hour-per-screen manual rewrite to a 4-hour automated extraction, the $100k monthly burn is extinguished in a fraction of the time.

Why the "Big Bang" Rewrite Fails (70% of the Time)#

The $3.6 trillion global technical debt isn't for lack of trying. Most enterprises attempt a "Big Bang" rewrite. They hire a massive SI (System Integrator), spend six months on "discovery," and another 18 months building.

The problem? Documentation archaeology.

67% of legacy systems lack accurate documentation. When you ask a developer to rewrite a system built in 2005, they aren't just coding; they are guessing. They are trying to infer business logic from a black box. This is why 70% of legacy rewrites fail or exceed their timeline. They hit a "logic wall" where the original intent of the software is lost to time.

⚠️ Warning: Attempting a rewrite without a "source of truth" for your business logic is the fastest way to double your technical debt.

Visual Reverse Engineering: The Future of Modernization#

At Replay, we argue that the future isn't rewriting from scratch—it's understanding what you already have. We use Visual Reverse Engineering. Instead of digging through 20-year-old spaghetti code, we record real user workflows.

By using video as the source of truth, Replay's AI Automation Suite extracts the underlying architecture, API contracts, and UI components. We turn the "black box" into a documented, modern React codebase.

How Replay Transforms the Workflow#

• •Library: Automatically generates a Design System from your legacy UI.
• •Flows: Maps out the architectural journey of a user through the system.
• •Blueprints: An editor that allows you to refine the extracted components before deployment.

Step-by-Step: Moving from EOL to Modern React in Days#

If you are currently paying the $100k-per-month cost, follow this actionable framework to modernize using Replay.

Step 1: Technical Debt Audit & Recording#

Identify the high-value, high-risk screens. Instead of manual discovery, have a subject matter expert (SME) perform the task while Replay records the session. Replay doesn't just record pixels; it records the DOM changes, network calls, and state transitions.

Step 2: Component Extraction#

Replay's AI analyzes the recording and generates modular React components. It identifies patterns—buttons, inputs, tables—and maps them to a modern Design System.

typescript
// Example: Component generated by Replay from a 2008 legacy ERP screen
// Logic is preserved, but the implementation is modern React + Tailwind

import React, { useState, useEffect } from 'react';
import { Button, Input, Table } from '@/components/ui'; // From Replay Library

export const LegacyInventoryModule = ({ initialData }) => {
  const [items, setItems] = useState(initialData);
  const [loading, setLoading] = useState(false);

  // Replay extracted this specific validation logic from the legacy network trace
  const handleUpdate = async (id: string, quantity: number) => {
    if (quantity < 0) return console.error("Inventory cannot be negative");
    
    setLoading(true);
    try {
      // Replay generated the API contract based on recorded legacy traffic
      const response = await fetch(`/api/v1/inventory/${id}`, {
        method: 'PATCH',
        body: JSON.stringify({ qty: quantity }),
      });
      const updatedItem = await response.json();
      setItems(prev => prev.map(item => item.id === id ? updatedItem : item));
    } finally {
      setLoading(false);
    }
  };

  return (
    <div className="p-6 bg-slate-50 rounded-xl border">
      <h2 className="text-xl font-bold mb-4">Inventory Management</h2>
      <Table 
        data={items} 
        onAction={handleUpdate} 
        isLoading={loading}
      />
    </div>
  );
};

Step 3: API Contract Generation#

One of the biggest hurdles in modernization is the backend. Replay monitors the network tab during your recording and generates Swagger/OpenAPI documentation automatically. This bridges the gap between your legacy backend and your new frontend.

yaml
# Generated by Replay AI Automation Suite
openapi: 3.0.0
info:
  title: Legacy ERP Inventory API
  version: 1.0.0
paths:
  /api/v1/inventory/{id}:
    patch:
      summary: Update inventory quantity
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: string
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                qty:
                  type: integer

Step 4: E2E Test Automation#

To ensure zero regression, Replay generates Playwright or Cypress tests based on the recorded user flow. This ensures that the new system behaves exactly like the old one, satisfying the strict requirements of regulated industries like Financial Services or Healthcare.

💡 Pro Tip: Use Replay's "Flows" feature to visualize complex state machines that have been buried in legacy code for decades. This is the "Documentation without Archaeology" promise.

The Financial Impact: From 18 Months to 8 Weeks#

When you stop the manual rewrite and start the visual extraction process, the math changes.

Instead of an 18-month timeline where you spend $1.8M just to get back to parity, you spend 8 weeks. You eliminate the $100k-per-month cost by month three, resulting in a massive net-positive ROI within the first fiscal year.

• •Manual Cost: 18 months x $100k/mo = $1.8M + $2M development cost = $3.8M
• •Replay Cost: 2 months x $100k/mo = $200k + $300k development cost = $500k
• •Total Savings: $3.3M

Built for Regulated Environments#

We understand that "legacy" often means "critical." Replay is built for the enterprise. Whether you are in Insurance, Government, or Telecom, security is non-negotiable.

• •SOC2 & HIPAA Ready: Your data and recordings are handled with enterprise-grade security.
• •On-Premise Available: For air-gapped environments or highly sensitive government systems, Replay can run entirely within your infrastructure.
• •Technical Debt Audit: Replay provides a comprehensive report of what was modernized and what remains, providing a clear roadmap for the board.

Frequently Asked Questions#

How does Replay handle complex business logic hidden in the backend?#

Replay focuses on the "User-to-System" interaction. By capturing the data sent, the state changes, and the UI response, we create a functional blueprint of the business logic. While we don't "decompile" your COBOL backend, we provide the exact API contracts and frontend logic required to interface with it or replace it incrementally.

What is the learning curve for my team?#

If your team knows React and TypeScript, they can use Replay. Replay generates standard, clean code. There is no proprietary "Replay Language." You own the code it generates.

Can Replay work with "Green Screen" or Terminal-based systems?#

Yes. Through our visual capture and OCR integration, we can map terminal-based workflows into modern web components, effectively "web-enabling" legacy mainframe systems in a fraction of the time.

How long does a typical extraction take?#

A single complex enterprise screen typically takes 40 hours to manually document and rewrite. With Replay, that same screen is recorded, analyzed, and converted into a functional React component in approximately 4 hours.

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