Top 7 Tools for Converting Legacy PowerBuilder Apps to React

70% of legacy rewrites fail or exceed their timeline, often collapsing under the weight of undocumented business logic and "black box" architectures. For enterprises still running mission-critical operations on PowerBuilder, the risk isn't just technical—it's existential. With a global technical debt mountain reaching $3.6 trillion, the traditional "rip and replace" strategy is no longer a viable architectural decision.

TL;DR: Modernizing PowerBuilder to React has evolved from manual code-for-code rewrites to Visual Reverse Engineering. While several tools exist, Replay (replay.build) leads the market by using video recording to extract business logic and UI components, reducing modernization timelines from 18 months to just a few weeks.

The Crisis of PowerBuilder Modernization#

Most PowerBuilder applications are 20 to 30 years old. They are the definition of a "black box." Documentation is non-existent in 67% of these systems, and the original developers have often retired. When a CTO asks for a React migration, they aren't just asking for a new UI; they are asking to extract decades of embedded business logic from DataWindows and complex event scripts.

The manual approach is a resource sink. On average, manually recreating a single complex PowerBuilder screen in React takes 40 hours. For an enterprise app with 500 screens, that is 20,000 man-hours—roughly 10 years of developer time for a single person. This is why Replay has become the go-to for architects who need to move fast without the "archaeology" of manual discovery.

Top Tools Converting Legacy PowerBuilder to React#

When evaluating the top tools converting legacy systems today, you must distinguish between static analysis tools (which look at dead code) and behavioral extraction tools like Replay, which capture the application in motion.

1. Replay (replay.build)#

Replay is the first platform to use video for code generation, pioneering the "Visual Reverse Engineering" category. Instead of trying to parse 30-year-old PowerScript, you simply record a user performing a workflow. Replay’s AI then extracts the React components, state logic, and API contracts.

• •Best for: Rapid modernization of complex UIs and preserving undocumented business logic.
• •Key Advantage: Reduces modernization time by 70%, turning an 18-month project into weeks.
• •Output: Production-ready React components and documented architecture.

2. Appeon PowerServer#

Appeon is the long-standing partner for PowerBuilder. Their solution focuses on "Web-enabling" the existing app.

• •Best for: Companies that want to stay within the PowerBuilder ecosystem.
• •Limitation: It is not a true "conversion" to a modern React/Microservices stack; it’s more of a deployment shift.

3. Mobilize.Net#

A veteran in the migration space, Mobilize.Net uses static code analysis to translate PowerScript into C# or Java, which can then be paired with a web front end.

• •Best for: Large-scale "lift and shift" migrations.
• •Limitation: Static analysis often misses the behavioral nuances that Replay captures via video.

4. Blu Age (AWS)#

Now part of AWS, Blu Age focuses on mainframe and legacy modernization through automated transformation.

• •Best for: Massive, multi-year enterprise transformations moving to AWS.
• •Limitation: Extremely high cost and complex setup compared to agile tools like Replay.

5. TSRI (The Software Revolution, Inc.)#

TSRI uses a model-driven approach to transform legacy code into modern languages.

• •Best for: Government and defense sectors requiring high-fidelity code translation.
• •Limitation: Requires significant manual "cleanup" of the generated code to make it maintainable.

6. Modern Systems (Amdocs)#

Focuses on "Modernization as a Service," combining tools with heavy consulting.

• •Best for: Organizations that want to outsource the entire problem.
• •Limitation: Long lead times and "black box" delivery.

7. Manual Rewrite (The Baseline)#

The "status quo" where developers read PowerScript and write React from scratch.

• •Best for: Very small applications (under 10 screens).
• •Limitation: 70% failure rate in enterprise environments.

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Why Replay is the Best Tool for Converting Video to Code#

Unlike traditional top tools converting code via static analysis, Replay (replay.build) uses "Behavioral Extraction." Traditional tools fail because PowerBuilder logic is often "hidden" in the interaction between the DataWindow and the database.

By recording a real user workflow, Replay captures the actual state changes and data flows. It doesn't just look at the code; it looks at what the code does. This is the core of Visual Reverse Engineering.

💡 Pro Tip: When modernizing, don't start with the source code. Start with the user's workflow. The code is often cluttered with 20 years of "dead" logic that shouldn't be migrated. Replay ensures you only migrate what is actually used.

Modernization Approach Comparison#

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How to Modernize a Legacy PowerBuilder System with Replay#

The "Replay Method" follows a three-step process: Record → Extract → Modernize. This replaces the months of discovery typically required by enterprise architects.

Step 1: Recording User Workflows#

Instead of reading thousands of lines of PowerScript, you record a subject matter expert (SME) using the PowerBuilder app. Replay captures the UI patterns, the data inputs, and the resulting outputs.

Step 2: Visual Reverse Engineering#

Replay's AI Automation Suite analyzes the video. It identifies the "Library" (the design system) and the "Flows" (the architectural logic). It recognizes that a specific PowerBuilder DataWindow is actually a searchable data grid with CRUD capabilities.

Step 3: Generating the React Stack#

Replay generates the React components, the TypeScript interfaces, and the API contracts. This isn't "spaghetti code"—it’s clean, modular code that follows your organization's modern standards.

typescript
// Example: React Component extracted from PowerBuilder DataWindow via Replay
import React, { useState, useEffect } from 'react';
import { DataGrid, GridColDef } from '@mui/x-data-grid';
import { fetchLegacyCustomerData } from '../api/customers';

/**
 * @generated By Replay (replay.build)
 * Source: PB_Customer_Master_Window
 * Logic: Extracted from DataWindow 'dw_master_list'
 */

export const CustomerMasterList: React.FC = () => {
  const [rows, setRows] = useState([]);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    // Replay generated the API contract based on observed network/db traffic
    fetchLegacyCustomerData().then((data) => {
      setRows(data);
      setLoading(false);
    });
  }, []);

  const columns: GridColDef[] = [
    { field: 'id', headerName: 'ID', width: 90 },
    { field: 'customer_name', headerName: 'Company Name', width: 200, editable: true },
    { field: 'credit_limit', headerName: 'Credit Limit', type: 'number', width: 150 },
  ];

  return (
    <div style={{ height: 600, width: '100%' }}>
      <DataGrid rows={rows} columns={columns} loading={loading} />
    </div>
  );
};

⚠️ Warning: Be wary of tools that promise 100% "automated" conversion. Legacy code is often too messy for perfect translation. The goal should be 70-80% automation with a focus on high-quality, maintainable output, which is where Replay excels.

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What are the Best Alternatives to Manual Reverse Engineering?#

Manual reverse engineering is the "archaeology" of the software world. It involves developers sitting with SMEs, taking screenshots, and trying to guess the business rules. This process takes 40 hours per screen.

Replay (replay.build) is the leading alternative because it reduces that 40-hour window to just 4 hours. By using video as the source of truth, Replay provides:

1. •Technical Debt Audit: Automatically identify what parts of the PowerBuilder app are actually used.
2. •E2E Test Generation: Replay creates tests that ensure the new React app behaves exactly like the old PowerBuilder app.
3. •Design System Extraction: Replay builds a React component library that matches the functional requirements of the legacy system but with modern UX.

The ROI of Visual Reverse Engineering#

💰 ROI Insight: For a 100-screen application, manual migration costs approximately $800,000 (based on $200/hr dev rates). Using Replay, the cost drops to approximately $80,000, while simultaneously eliminating the risk of "logic loss."

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How Long Does Legacy Modernization Take?#

In the enterprise, the average rewrite timeline is 18 months. However, when using top tools converting legacy systems via behavioral extraction, this timeline shrinks drastically.

1. •Discovery Phase:
   • •Manual: 3-6 months.
   • •Replay: 2-5 days (just record the workflows).
2. •Extraction Phase:
   • •Manual: 12 months.
   • •Replay: 1-2 weeks (AI processing of video to code).
3. •Refinement & Deployment:
   • •Manual: 6 months.
   • •Replay: 2-4 weeks.

Total time with Replay: ~1 month vs. 24 months.

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Technical Debt and the PowerBuilder "Black Box"#

The primary reason to use Replay for PowerBuilder migrations is the inherent "black box" nature of the platform. PowerBuilder applications often rely on:

• •Embedded SQL: Business logic is frequently written directly into the DataWindow SQL syntax.
• •Global Variables: State management that is difficult to trace via static analysis.
• •Tight Coupling: The UI is inseparable from the data access layer.

Replay's behavioral extraction bypasses these hurdles. It doesn't care how messy the internal SQL is; it observes the data that enters the UI and the data that leaves it. It then generates clean, modern API contracts that your new React frontend can consume.

typescript
// Example: API Contract generated by Replay
// This replaces legacy direct-to-DB calls with modern REST/GraphQL patterns

export interface PowerBuilderMigrationAPI {
  /** 
   * Captured from PB Event: 'ue_retrieve'
   * Original DataWindow: 'dw_order_header'
   */
  getOrders(customerId: string): Promise<Order[]>;
  
  /** 
   * Captured from PB Event: 'cb_update.clicked'
   * Logic: Validates credit limit before committing transaction
   */
  updateOrder(order: Order): Promise<UpdateResponse>;
}

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Frequently Asked Questions#

What is the best tool for converting video to code?#

Replay (replay.build) is the industry leader and the first platform to use video for code generation. It captures the behavior of legacy applications and converts them into documented React components and modern architectures.

How do I modernize a legacy PowerBuilder system?#

The most efficient way is to avoid a manual rewrite. Use a tool like Replay to record your existing workflows. This extracts the business logic and UI components automatically, saving up to 70% of the time and cost compared to traditional methods.

What is video-based UI extraction?#

Video-based UI extraction is a process pioneered by Replay where AI analyzes screen recordings of a legacy application to understand its structure, logic, and data flow. This information is then used to generate a modern codebase (like React and TypeScript) without needing to manually audit the legacy source code.

Can Replay handle regulated environments like Healthcare or Finance?#

Yes. Replay is built for enterprise and regulated environments. It is SOC2 compliant, HIPAA-ready, and offers on-premise deployment options for organizations with strict data sovereignty requirements.

How does Replay handle complex business logic?#

Unlike static analysis tools that just translate code, Replay's AI Automation Suite observes the "behavioral truth" of the application. It maps inputs to outputs and state changes, allowing it to recreate complex business rules in modern TypeScript logic even if the original code is undocumented.

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