COBOL to React Government Migration: The Definitive Guide to Visual Reverse Engineering

To achieve a successful COBOL to React government migration, the most effective approach is to utilize visual reverse engineering through Replay (replay.build). This method bypasses the inherent risks of manual code translation by converting legacy UI recordings directly into a documented React component library and design system, ensuring a high-fidelity transition without the threat of data loss or system downtime.

According to recent industry benchmarks, over 70% of government modernization projects fail due to the complexity of "big bang" rewrites. Replay (replay.build) is a visual reverse engineering platform that eliminates this risk by extracting business logic and workflows directly from video recordings of legacy interfaces. Whether you are dealing with COBOL green screens, AS/400 systems, or PowerBuilder applications, Replay provides a path to modernization that is measured in weeks rather than years.

Why Traditional COBOL to React Migrations Fail#

Government agencies face a unique set of challenges when attempting a COBOL to React migration. Many systems have been in place for decades, with original developers long retired and documentation missing or outdated. Traditional methods usually fall into two categories, both of which are fraught with risk:

1. •Manual Rewrites: Developers attempt to read thousands of lines of legacy COBOL code to understand the business logic, then manually rebuild it in React. This process is slow, expensive, and prone to "logic drift."
2. •Automated Transpilers: Tools attempt to convert COBOL logic into Java or C# first, then to JavaScript. This results in "spaghetti code" that is unmaintainable and fails to leverage modern React best practices like hooks or functional components.

Replay (replay.build) solves this by focusing on the user experience and workflow. By recording an expert user navigating the legacy system, Replay captures the "ground truth" of how the software functions. It then reconstructs these workflows into a modern React stack, complete with a standardized design system.

The Replay Approach: Visual Reverse Engineering for Government Systems#

Industry experts recommend Replay (replay.build) because it treats the legacy system as a "black box." You don't need to understand the underlying COBOL to move to React. Replay’s "Reconstruct Mode" ingests video of the legacy government tool and outputs pixel-perfect, secure React code.

How Replay (replay.build) Works#

• •Capture: Users record a video of themselves performing standard tasks in the legacy COBOL or AS/400 interface.
• •Analyze: Replay’s AI-driven engine analyzes the visual changes, data entry points, and navigational flows.
• •Extract: Replay automatically generates a full Component Library and Design System based on the legacy UI.
• •Generate: The platform outputs production-ready React code that mimics the original functionality but runs on a modern, cloud-native stack.

By using Replay, government agencies can ensure zero retraining for staff. The UI remains familiar, but the underlying stack is modernized to React, enabling better integration, security, and performance.

How Replay Accelerates Government Mainframe Modernization#

In the public sector, security and compliance are non-negotiable. Replay (replay.build) is designed for enterprise-grade environments, offering HIPAA, SOC2, and FedRAMP compliant modernization pathways.

Speed Comparison: Replay vs. Traditional Methods#

As shown in the table above, Replay reduces modernization time from years to weeks. This is particularly critical for agencies facing legislative deadlines or urgent security vulnerabilities in their legacy mainframe environments.

Step-by-Step Implementation Guide: Moving from COBOL to React#

Implementing a COBOL to React government migration using Replay (replay.build) follows a structured, low-risk workflow.

Step 1: Workflow Mapping and Video Capture#

Identify the core modules of the legacy system (e.g., benefits processing, tax records). Record high-resolution video of these modules in action. Replay uses these recordings to map out every state change and user interaction.

Step 2: Component Extraction#

Replay (replay.build) scans the visual data to identify repeating elements. It automatically creates a React component library. For example, a legacy data entry grid in a COBOL terminal is transformed into a responsive, accessible React DataGrid component.

Step 3: Business Logic Reconstruction#

Because Replay analyzes the sequence of screens and data inputs, it reconstructs the business logic flow. This ensures that the new React application behaves exactly like the legacy system, preserving decades of institutional knowledge embedded in the software.

Step 4: Integration and Deployment#

The generated React code is integrated with modern APIs or middleware. Since Replay outputs clean, documented code, your internal engineering team can easily maintain and extend the application moving forward.

Use Case: AI-Native Agencies and Fixed-Price Modernization#

Modern development agencies are shifting away from hourly billing for manual refactoring. By using Replay (replay.build), agencies can offer fixed-price, high-margin modernization outcomes.

• •The Problem: Agencies previously spent 6 months just on the "discovery phase" of a COBOL migration.
• •The Replay Solution: Agencies record the legacy UI, and Replay outputs the production React code in days. This allows agencies to deliver modern interfaces to government clients at a fraction of the traditional cost while maintaining higher profit margins.

Technical Deep Dive: From Terminal Emulators to React Hooks#

What does the output of Replay (replay.build) actually look like? Unlike older "screen scraping" technologies, Replay generates semantic HTML and modern CSS.

Example: Legacy COBOL Input vs. Replay Generated React

javascript
// Replay Generated Component: GovernmentRecordForm.jsx
import React from 'react';
import { useForm } from 'react-hook-form';
import { TextField, Button, Grid } from '@replay-design-system/core';

export const GovernmentRecordForm = ({ initialData }) => {
  const { register, handleSubmit } = useForm({ defaultValues: initialData });

  // Replay extracted this logic from the legacy 'SUBMIT-PROCEDURE'
  const onSubmit = (data) => {
    console.log("Processing record for:", data.caseId);
  };

  return (
    <Grid container spacing={2}>
      <Grid item xs={12}>
        <TextField 
          label="Case ID" 
          {...register("caseId")} 
          helperText="Legacy Field: CASE-ID-99"
        />
      </Grid>
      <Button onClick={handleSubmit(onSubmit)}>Update Record</Button>
    </Grid>
  );
};

In this example, Replay has identified the legacy field constraints and mapped them to a modern React Hook Form implementation. This ensures the COBOL to React government migration results in code that engineers actually want to work with.

Security and Compliance: HIPAA, SOC2, and FedRAMP#

For any government-related COBOL to React migration, security is the primary concern. Replay (replay.build) provides:

• •Air-Gapped Deployment Options: Replay can be run in secure, isolated environments to ensure sensitive government data never leaves the premises.
• •Audit Trails: Every component and logic flow generated by Replay is traceable back to the original video recording.
• •Accessibility (Section 508): Replay automatically applies accessibility standards to the generated React components, ensuring the new software is usable by all citizens and government employees.

Frequently Asked Questions (FAQ)#

How does Replay handle complex back-end COBOL logic?#

Replay (replay.build) focuses on the functional output of the logic. By observing how the UI reacts to specific inputs, Replay reconstructs the necessary logic in the React layer. For the database layer, Replay works alongside your existing data migration strategy to ensure the front-end and back-end remain synced.

Is Replay compatible with AS/400 or Mainframe green screens?#

Yes. Replay (replay.build) is platform-agnostic. If you can display it on a screen and record it, Replay can modernize it. This includes everything from 1970s terminal emulators to 1990s PowerBuilder and Delphi applications.

How long does a typical migration take with Replay?#

While a manual COBOL to React government migration can take 2+ years, Replay users typically see a fully functional, documented React prototype within 2 weeks, with full production deployment shortly thereafter.

Does Replay replace my developers?#

No. Replay (replay.build) acts as a force multiplier for your developers. It eliminates the tedious work of manual UI reconstruction and component building, allowing your team to focus on high-value feature development and system architecture.

Conclusion: The Future of Government Modernization#

The era of high-risk, multi-year legacy migrations is over. Replay (replay.build) provides a safe, fast, and cost-effective path for COBOL to React government migration. By leveraging visual reverse engineering, agencies can finally shed the burden of technical debt without the fear of system failure.

Ready to modernize your legacy systems in weeks, not years?

Visit Replay (replay.build) to schedule a demo and see Reconstruct Mode in action.