The Death of the TWebModule: Why Your Delphi Broker Modernization Must Be Practical

Your Delphi Web Broker application is likely a "zombie" system. It’s stable, it’s mission-critical, and it’s currently eating your maintenance budget alive. While Web Broker was a revolutionary way to build web applications in the late 90s and early 2000s, it has become a significant contributor to the $3.6 trillion global technical debt crisis. The challenge isn't just that the UI looks like a Windows 95 time capsule; it’s that the business logic is inextricably tangled with HTML-generating Pascal code.

Most enterprise architects look at these systems and see two bad options: keep paying the "Delphi tax" for specialized developers or attempt a high-risk "big bang" rewrite. Industry experts recommend a third way. By focusing on a delphi broker modernization practical approach, you can decouple your frontend from your legacy backend without the 70% failure rate associated with total rewrites.

TL;DR:

• •Delphi Web Broker systems suffer from tight coupling of UI and logic, making them hard to maintain.
• •Traditional manual rewrites take 18-24 months and often fail due to lack of documentation (67% of systems).
• •Replay uses Visual Reverse Engineering to convert recorded legacy workflows into documented React components, reducing modernization time by 70%.
• •A practical path involves moving to a React-based "High-Code" architecture while keeping stable Delphi logic as a headless API.

The High Cost of the "Big Bang" Rewrite#

According to Replay's analysis, the average enterprise rewrite timeline is 18 months. For a Delphi Web Broker application, this timeline is often optimistic. Because 67% of legacy systems lack documentation, developers spend more time "archaeologizing" the Pascal source code than actually writing new features.

When you attempt a manual migration of a Web Broker app, you are fighting against

logic and strings. Manually translating these into modern React components takes approximately 40 hours per screen. In a system with 100+ screens, you are looking at years of work before the first user sees a login page.

Video-to-code is the process of capturing real-time user interactions with a legacy interface and using AI-driven visual analysis to generate production-ready frontend code, documentation, and design tokens.

Replay automates this transition. Instead of staring at legacy Pascal files, you record the application in use. Replay’s engine analyzes the visual output and generates a modern React Design System and Component Library in hours, not months.

A Delphi Broker Modernization Practical Framework#

To move from a monolithic Web Broker setup to a modern React architecture, you need a strategy that prioritizes business continuity. A delphi broker modernization practical strategy follows the "Strangler Fig" pattern: gradually replacing UI elements while the legacy system continues to handle heavy-duty data processing.

Step 1: Visual Capture and Reverse Engineering#

The first hurdle is the UI. Web Broker often uses

or raw string concatenation to build HTML. This makes extracting a clean design system nearly impossible through traditional code analysis. By using Replay to record user flows, you bypass the messy source code and capture the intended user experience.

Step 2: Componentization#

Once captured, Replay’s Library feature organizes these visual elements into a standardized Design System. This moves you away from the "spaghetti HTML" of Delphi and into a structured React environment.

Step 3: Decoupling the Backend#

Instead of

returning HTML, you refactor your Delphi actions to return JSON. This transforms your legacy app into a "Headless" API provider, which your new React frontend (generated by Replay) can consume.

Comparing Modernization Paths#

Implementation: From Pascal Strings to React Components#

Let’s look at why a delphi broker modernization practical approach is necessary at the code level. In a traditional Web Broker application, your UI logic is likely trapped inside an event handler like this:

pascal
// The Legacy Problem: UI inside the Backend
procedure TWebModule1.WebModule1WebActionItem1Action(Sender: TObject;
  Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
  Response.Content := 
    '<html><body>' +
    '<h1>Customer Data: ' + Request.QueryFields.Values['ID'] + '</h1>' +
    '<table class="legacy-grid">' +
    '<tr><td>Name:</td><td>' + GetCustomerName(Request.QueryFields.Values['ID']) + '</td></tr>' +
    '</table>' +
    '</body></html>';
end;

This code is a nightmare for modern developers. It's un-testable, un-styleable, and requires a Delphi expert to change a single CSS class.

Using Replay, you don't need to manually pick apart that string concatenation. You record the screen where this table appears, and Replay generates a clean, typed React component. Here is what the modernized output looks like after Replay’s AI Automation Suite processes the recording:

typescript
// The Modern Solution: Generated by Replay
import React from 'react';
import { useCustomerData } from './api/hooks';
import { Card, Grid, Typography, Skeleton } from '@/components/design-system';

interface CustomerViewProps {
  customerId: string;
}

/**
 * Modernized Customer View Component
 * Generated via Replay Visual Reverse Engineering
 */
export const CustomerView: React.FC<CustomerViewProps> = ({ customerId }) => {
  const { data, isLoading, error } = useCustomerData(customerId);

  if (isLoading) return <Skeleton className="h-40 w-full" />;
  if (error) return <div>Error loading customer data.</div>;

  return (
    <Card className="p-6 shadow-lg">
      <Typography variant="h1" className="mb-4">
        Customer Data: {customerId}
      </Typography>
      <Grid cols={2} gap={4}>
        <div className="font-bold">Name:</div>
        <div>{data?.name}</div>
      </Grid>
    </Card>
  );
};

By moving to this "High-Code" React structure, you've achieved two things: you've modernized the stack, and you've made the system accessible to the millions of React developers available in the current talent pool. For more on this, see our guide on React Design Systems.

Why Visual Reverse Engineering is the Key#

The reason a delphi broker modernization practical project often stalls is the sheer volume of "hidden" logic in the UI. Delphi developers often put validation logic, conditional formatting, and state management directly into the HTML generation layer.

Replay’s Flows feature acts as an architectural map. It doesn't just look at one screen; it understands how a user moves from a search results page to a detailed record view. According to Replay's analysis, capturing these flows visually reduces the discovery phase of a project by 80%.

The Replay AI Automation Suite#

Modernization isn't just about code; it's about context. Replay’s AI suite analyzes the captured video to:

1. •Identify Components: Recognize that a specific table structure is actually a "Data Grid" and map it to a modern equivalent.
2. •Extract Design Tokens: Pull hex codes, spacing, and typography from the legacy app to seed a modern Tailwind or CSS-in-JS theme.
3. •Generate Documentation: Create a functional specification based on how the app actually behaves, solving the "67% lack of documentation" problem.

Learn more about Visual Reverse Engineering and how it's changing the enterprise landscape.

Security and Compliance in Regulated Industries#

If you are running a Delphi Web Broker app, there is a high probability you are in Financial Services, Healthcare, or Government. These are environments where "moving fast and breaking things" isn't an option.

Replay is built for these regulated environments. With SOC2 and HIPAA-ready standards, and the ability to run On-Premise, Replay ensures that your sensitive data never leaves your controlled environment during the modernization process. You can record your legacy workflows behind your firewall, and the generated React code remains entirely under your control.

The Practical Timeline: From 18 Months to 18 Days#

When we talk about a delphi broker modernization practical path, we are talking about radical efficiency.

1. •Week 1: Discovery & Capture. Record all primary user workflows using Replay.
2. •Week 2: Library Generation. Replay generates the Component Library and Design System. Your frontend leads review and tweak the generated React code.
3. •Week 3: Integration. Use Replay's Blueprints to map the new React components to your now-headless Delphi API.

This timeline is only possible because Replay reduces the manual labor from 40 hours per screen to 4 hours per screen. You aren't rebuilding the wheel; you're just giving the vehicle a modern engine and a sleek new body.

Frequently Asked Questions#

Is Delphi Web Broker still supported in modern Delphi versions?#

Yes, Embarcadero still supports Web Broker in the latest versions of Delphi (12 Athens). However, while the framework is supported, it lacks the modern features required for responsive design, SEO, and complex client-side state management that React provides out of the box.

How does Replay handle complex business logic inside Pascal files?#

Replay focuses on the "Visual Reverse Engineering" of the frontend. It captures the behavior and the UI. This allows you to keep your complex business logic in Delphi (accessible via REST/JSON) while completely replacing the UI layer with modern React code. It effectively "de-couples" the logic from the presentation.

Can Replay generate TypeScript instead of plain JavaScript?#

Yes. Replay’s AI Automation Suite is designed for "High-Code" environments. It generates clean, type-safe TypeScript and React code that follows modern best practices, including hooks, functional components, and modular CSS.

What happens to my old Delphi server?#

In a delphi broker modernization practical approach, your Delphi server usually evolves into a backend API service. You replace the HTML-producing

with ones that return JSON. This allows you to leverage your existing, tested business logic while serving a modern React frontend.

Is Replay a Low-Code tool?#

No. Replay is a Visual Reverse Engineering platform that generates "High-Code." The output is standard React/TypeScript that your developers own, edit, and maintain. There is no vendor lock-in; once the code is generated, it's yours.

The Path Forward#

The $3.6 trillion technical debt mountain won't move itself. For organizations running on legacy Delphi Web Broker systems, the risk of doing nothing is now higher than the risk of modernizing. By choosing a delphi broker modernization practical path, you bypass the failures of the past and move directly into a high-performance React future.

Stop treating your legacy systems like a burden and start treating them like a blueprint. With Replay, you can turn those decades of business logic into a modern, scalable, and documented React ecosystem in a fraction of the time.

Ready to modernize without rewriting? Book a pilot with Replay