CA Gen Legacy Portals: Simplifying Model-Based UI Migrations through Visual Reverse Engineering

The $3.6 trillion global technical debt crisis isn't just a number on a balance sheet; it is the physical weight of millions of lines of CA Gen Action Blocks and "Web Generation" wrappers that refuse to scale. For decades, Computer-Aided Software Engineering (CASE) tools promised a future where models would dictate business logic forever. Instead, enterprise architects are now trapped in a "model-based cage," where the very tools meant to simplify development have become the primary blockers to digital transformation.

CA Gen (formerly IEF/Cool:Gen) was built on a promise: define the model, generate the code. But as these systems aged, the documentation vanished. Industry experts recommend a shift away from the "rip-and-replace" mentality that has plagued the last decade. According to Replay’s analysis, 70% of legacy rewrites fail or exceed their timeline because teams attempt to manually reverse-engineer complex model-based logic that no longer has a living author.

When dealing with legacy portals simplifying modelbased migrations, the challenge isn't just the code—it’s the behavior. The UI of a CA Gen application is often a complex web of screen flows, hidden validations, and deeply nested action blocks. Traditional migration strategies involve parsing the model itself, a process that is prone to error and incredibly time-consuming.

Replay offers a different path: Visual Reverse Engineering. By recording the actual user workflows of these legacy portals, Replay bypasses the "black box" of the CA Gen model and generates documented React components and design systems directly from the source of truth—the running application.

TL;DR: CA Gen migrations are notoriously difficult due to missing documentation and rigid model-based architectures. Manual rewrites take an average of 18-24 months and often fail. By using legacy portals simplifying modelbased strategies via Replay's Visual Reverse Engineering, enterprises can reduce screen development time from 40 hours to just 4 hours. Replay converts video recordings of legacy workflows into clean, documented React code, enabling a 70% time savings and a faster path to a modern Design System.

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The CA Gen Deadlock: Why Traditional Migrations Fail#

CA Gen was designed to be platform-independent, but it created a unique form of vendor lock-in. The logic is stored in a proprietary "Encyclopedia," and the UIs are often generated as clunky Java or C# wrappers that feel like 1995.

The Documentation Vacuum#

67% of legacy systems lack documentation. In a CA Gen environment, this is compounded by the fact that the "documentation" is the model. If the model is poorly maintained or the original architects have retired, the system becomes a black box. Developers are left guessing how a specific "Guard Condition" or "Action Block" translates to a modern user experience.

The Complexity of Model-Based Logic#

When we talk about legacy portals simplifying modelbased migrations, we must address the sheer density of the logic. A single screen in a CA Gen portal might trigger dozens of background processes across multiple mainframe modules. Attempting to manually map these to a modern React state management system is a recipe for scope creep.

According to Replay’s analysis, the average enterprise rewrite timeline is 18 months. Much of this time is spent in discovery—the painful process of clicking through every possible permutation of a legacy UI to understand what it actually does.

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Legacy Portals: Simplifying Model-Based Migrations with Visual Reverse Engineering#

To break the deadlock, we need to stop looking at the model and start looking at the result. This is where the concept of Visual Reverse Engineering changes the game.

Video-to-code is the process of capturing high-fidelity screen recordings of legacy application workflows and using AI-driven automation to transform those visual elements and interaction patterns into clean, production-ready frontend code.

By focusing on the UI behavior, Replay allows organizations to achieve legacy portals simplifying modelbased transitions without needing to decode the underlying COBOL or Action Blocks immediately. You capture the "what" so you can build the "new."

The Replay Workflow: From Recording to React#

1. •Record: A subject matter expert (SME) records a standard workflow in the legacy CA Gen portal (e.g., "Onboard New Policyholder").
2. •Analyze: Replay’s AI analyzes the layout, spacing, typography, and interactive elements.
3. •Generate: The platform produces a documented React component library and a structured Design System.
4. •Flows: Replay maps the "Flows" or architecture of the application, ensuring that the navigation logic of the legacy portal is preserved in the modern version.

Learn more about Visual Reverse Engineering

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Comparing Migration Strategies: Manual vs. Replay#

The difference between manual migration and an automated, visual-first approach is staggering. For a typical financial services portal with 200+ screens, the manual effort is often insurmountable.

As seen above, legacy portals simplifying modelbased migrations via Replay provides a 10x improvement in delivery speed. This isn't just about code generation; it's about the Library (Design System) and Blueprints (Editor) that ensure the new application is maintainable.

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Technical Deep Dive: From CA Gen to Modern React#

When Replay captures a CA Gen portal, it doesn't just "scrape" the HTML. It understands the underlying intent. A legacy CA Gen screen might use a complex table structure for a simple form. Replay identifies these patterns and generates clean, accessible React code.

Example: Legacy Data Grid Transformation#

In a CA Gen "Web Generation" portal, a data grid might be rendered with nested tables and inline styles. Replay identifies this as a

component and applies the enterprise's modern design tokens.

typescript
// Generated React Component from a CA Gen Legacy Recording
import React from 'react';
import { DataTable, Button, Badge } from '@/components/design-system';

interface PolicyRecord {
  id: string;
  holderName: string;
  status: 'Active' | 'Pending' | 'Expired';
  premium: number;
}

export const PolicyManagementTable: React.FC<{ data: PolicyRecord[] }> = ({ data }) => {
  return (
    <div className="p-6 bg-white rounded-lg shadow-sm">
      <h2 className="text-xl font-semibold mb-4">Policy Overview</h2>
      <DataTable 
        columns={[
          { header: 'Policy ID', accessor: 'id' },
          { header: 'Holder', accessor: 'holderName' },
          { 
            header: 'Status', 
            render: (row) => (
              <Badge variant={row.status === 'Active' ? 'success' : 'warning'}>
                {row.status}
              </Badge>
            )
          },
          { header: 'Premium', render: (row) => `$${row.premium.toLocaleString()}` }
        ]}
        data={data}
      />
      <div className="mt-4 flex gap-2">
        <Button variant="primary">Add New Policy</Button>
        <Button variant="secondary">Export to CSV</Button>
      </div>
    </div>
  );
};

Mapping Logic with Blueprints#

One of the most powerful features of Replay is the Blueprints editor. While the visual layer is captured, the business logic (the "Action Blocks" of the CA Gen world) needs a place to live. Replay's Blueprints allow architects to define the state transitions and API integrations that replace the legacy model logic.

typescript
// Blueprint Logic Definition for a Legacy Workflow
const handleOnboardingSubmit = async (formData: OnboardingData) => {
  // Replay helps identify the legacy endpoint mapping
  // Transitioning from CA Gen Action Block logic to modern REST/GraphQL
  try {
    const response = await api.post('/v1/onboarding', formData);
    if (response.status === 200) {
      // Navigate to the next captured 'Flow'
      router.push('/onboarding/success');
    }
  } catch (error) {
    console.error('Migration Logic Error:', error);
  }
};

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The Strategic Importance of "Flows" in Legacy Portals#

In a model-based environment, the "Flow" is everything. CA Gen applications are essentially state machines. If you lose the sequence of screens, you lose the application. Replay’s Flows feature automatically documents the sequence of events captured during the recording phase.

By visualizing these legacy portals simplifying modelbased transitions, enterprise architects can identify redundant steps in the legacy workflow. Many CA Gen portals were built with hardware limitations in mind, requiring users to jump through five screens for a task that can now be handled in one modern React form.

Read about Architecture Mapping in Legacy Systems

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Industry-Specific Benefits#

Financial Services & Insurance#

In highly regulated industries, the risk of a "failed rewrite" is not just financial—it's a compliance nightmare. Replay is built for these environments, offering SOC2 and HIPAA-ready configurations, with On-Premise availability for organizations that cannot send data to the cloud.

Government & Manufacturing#

For government agencies, CA Gen systems often hold 30+ years of citizen data. The legacy portals simplifying modelbased migration approach ensures that the "User Interface of Record" is preserved and modernized without touching the fragile mainframe backend until the frontend is stabilized.

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Overcoming the "Technical Debt" Gravity#

Technical debt is often described as "interest" paid on past shortcuts. In the case of CA Gen, the debt is the proprietary nature of the model itself. Industry experts recommend that instead of trying to pay off the debt by "refactoring" the model, organizations should "declare bankruptcy" on the legacy UI and use Replay to leapfrog into a modern stack.

According to Replay's analysis, 40 hours per screen is the manual average for discovery, design, and development of a legacy replacement. With Replay, this drops to 4 hours. This 90% reduction in manual effort allows teams to focus on high-value features rather than the drudgery of recreating legacy tables and buttons.

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Why Replay is the Standard for CA Gen Modernization#

Replay isn't just a code generator; it is a transformation platform. It provides:

• •Library: A centralized Design System that ensures every modernized screen looks and feels like part of a cohesive brand.
• •Flows: A visual map of your application’s architecture, derived from real usage.
• •Blueprints: An editor that bridges the gap between the captured UI and the target code.
• •AI Automation Suite: Tools that handle the heavy lifting of component extraction and documentation.

By focusing on legacy portals simplifying modelbased workflows, Replay allows you to modernize at the speed of business, not the speed of COBOL.

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Frequently Asked Questions#

How does Replay handle complex CA Gen Action Block logic?#

Replay focuses on the visual and behavioral output of the Action Blocks. By recording the UI's response to various inputs, Replay captures the intent of the logic. This allows developers to reimplement that logic in modern TypeScript or move it to a microservices layer, rather than trying to translate 40-year-old model code line-by-line.

Can Replay work with "green screen" terminal emulators?#

Yes. While CA Gen often uses "Web Generation" for portals, many systems still rely on 3270/5250 terminal emulators. Replay can record these sessions and transform the character-based UI into a modern, accessible React component library, effectively bridging the gap between the mainframe and the modern web.

Does Replay require access to the CA Gen Encyclopedia or source code?#

No. This is the primary advantage of Visual Reverse Engineering. Replay works by observing the application as a user does. This eliminates the need for complex "model crawlers" or proprietary access to legacy repositories, which are often the biggest bottlenecks in a migration project.

What is the typical ROI for a Replay-led migration?#

Most enterprises see a return on investment within the first three months. By reducing the time-per-screen from 40 hours to 4 hours, a project that would have taken 18 months can be completed in under 6 months. Additionally, the automated generation of documentation and a design system significantly reduces long-term maintenance costs. Calculate your potential savings.

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Moving Forward: From Model-Based to Component-Based#

The era of the "all-encompassing model" is over. The future of enterprise software is modular, component-based, and user-centric. Migrating from CA Gen doesn't have to be a multi-year slog through undocumented Action Blocks.

By leveraging legacy portals simplifying modelbased strategies with Replay, you can turn your legacy "black box" into a documented, modern React ecosystem in a fraction of the time. Don't let your technical debt dictate your roadmap.

Ready to modernize without rewriting? Book a pilot with Replay