Generating UI for Legacy Systems with Replay: Modernization Made Easy

TL;DR: Replay bridges the gap between outdated systems and modern UI frameworks by reconstructing functional code from screen recordings of existing legacy application workflows.

Legacy systems. They're the backbone of countless businesses, but often a developer's nightmare. Updating the UI? Forget about it. Rewriting from scratch? A multi-year project. But what if you could modernize your UI without a complete overhaul?

That's where Replay comes in. We're not just another screenshot-to-code tool. We analyze video, understand user behavior, and reconstruct functional UI components, bridging the gap between legacy systems and modern frameworks.

The Legacy UI Challenge: Why Modernization Stalls#

The pain points are real:

• •Outdated Technology: Cobol, Visual Basic 6, and other ancient technologies are hard to maintain and even harder to integrate with modern systems.
• •Lack of Documentation: Many legacy systems have little to no documentation, making it difficult to understand the underlying logic.
• •Risk of Disruption: Major changes to core systems can introduce instability and disrupt critical business processes.
• •Talent Shortage: Finding developers with expertise in legacy technologies is increasingly challenging.

This often leads to a standstill. Companies are stuck with clunky, inefficient UIs that hinder productivity and user experience.

Replay: Behavior-Driven Reconstruction for Legacy Modernization#

Replay offers a revolutionary approach: Behavior-Driven Reconstruction. Instead of relying on static screenshots, Replay analyzes video recordings of users interacting with the legacy UI. This allows it to understand the intent behind the actions, not just the visual appearance.

How it Works: Video to Working Code#

1. •Record: Capture a video of a user performing a specific task within the legacy system. This could be anything from creating a new customer record to generating a report.
2. •Analyze: Replay's engine, powered by Gemini, analyzes the video, identifying UI elements, user interactions, and the underlying logic.
3. •Reconstruct: Replay generates clean, functional code in a modern framework like React, Vue, or Angular.
4. •Integrate: Seamlessly integrate the reconstructed UI components into your modern application.

💡 Pro Tip: Focus your initial recordings on the most critical and frequently used workflows. This will provide the biggest immediate impact.

Key Features for Legacy Modernization#

• •Multi-Page Generation: Replay can reconstruct complex, multi-page workflows, ensuring a seamless user experience.
• •Supabase Integration: Easily connect your reconstructed UI to a modern database using Supabase, enabling data synchronization and persistence.
• •Style Injection: Maintain visual consistency with your existing design system by injecting custom styles into the generated code.
• •Product Flow Maps: Visualize complex workflows with automatically generated product flow maps, providing a clear understanding of the user journey.

Implementation: A Step-by-Step Example#

Let's say you have a legacy system for managing customer orders. A user needs to create a new order. Here's how you can modernize that workflow with Replay:

Step 1: Record the Workflow#

Use a screen recording tool (like OBS Studio or even Replay's built-in recorder) to capture a video of a user creating a new order in the legacy system. Make sure to capture all the steps, including:

• •Entering customer information
• •Selecting products
• •Applying discounts
• •Submitting the order

Step 2: Upload to Replay#

Upload the video to Replay. Our engine will analyze the video and begin reconstructing the UI.

Step 3: Review and Refine#

Review the generated code and make any necessary adjustments. Replay provides a visual editor that allows you to fine-tune the UI and ensure it meets your requirements.

Step 4: Integrate with Your Modern Application#

Integrate the reconstructed UI components into your modern application. You can use the generated code as a starting point and customize it further to fit your specific needs.

Code Example: Generated React Component#

typescript
// Example of a generated React component for a customer order form
import React, { useState } from 'react';

const CustomerOrderForm = () => {
  const [customerName, setCustomerName] = useState('');
  const [product, setProduct] = useState('');
  const [quantity, setQuantity] = useState(1);

  const handleSubmit = async (e) => {
    e.preventDefault();
    // Send data to your backend (e.g., Supabase)
    const response = await fetch('/api/createOrder', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ customerName, product, quantity }),
    });

    if (response.ok) {
      alert('Order created successfully!');
      // Reset form
      setCustomerName('');
      setProduct('');
      setQuantity(1);
    } else {
      alert('Failed to create order.');
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="customerName">Customer Name:</label>
        <input
          type="text"
          id="customerName"
          value={customerName}
          onChange={(e) => setCustomerName(e.target.value)}
        />
      </div>
      <div>
        <label htmlFor="product">Product:</label>
        <input
          type="text"
          id="product"
          value={product}
          onChange={(e) => setProduct(e.target.value)}
        />
      </div>
      <div>
        <label htmlFor="quantity">Quantity:</label>
        <input
          type="number"
          id="quantity"
          value={quantity}
          onChange={(e) => setQuantity(parseInt(e.target.value))}
        />
      </div>
      <button type="submit">Create Order</button>
    </form>
  );
};

export default CustomerOrderForm;

This is a simplified example, but it illustrates the basic concept. Replay can generate much more complex components, including data grids, charts, and other UI elements.

Benefits of Using Replay for Legacy Modernization#

• •Reduced Development Time: Replay automates the UI reconstruction process, significantly reducing development time and costs.
• •Lower Risk: By working with existing workflows, Replay minimizes the risk of introducing errors or disrupting critical business processes.
• •Improved User Experience: Modernize your UI with a clean, intuitive design that enhances user productivity and satisfaction.
• •Preserved Business Logic: Replay focuses on reconstructing the UI while preserving the underlying business logic of your legacy system.
• •Faster Time to Market: Get your modernized UI to market faster, enabling you to stay ahead of the competition.

Replay vs. Traditional Modernization Approaches#

⚠️ Warning: Replay works best when the video recordings are clear and focused. Avoid shaky footage or excessive background noise.

Real-World Use Cases#

• •Modernizing internal tools: Rebuild outdated internal applications with modern UIs, improving employee productivity and satisfaction.
• •Creating mobile-friendly interfaces: Generate responsive UIs that work seamlessly on mobile devices, expanding accessibility and reach.
• •Integrating legacy systems with modern platforms: Connect legacy systems with modern cloud platforms, enabling data sharing and workflow automation.
• •Building proof-of-concepts: Quickly create prototypes of modernized UIs to validate ideas and gather feedback.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited usage. Paid plans are available for more extensive use and advanced features.

How is Replay different from v0.dev?#

While both tools aim to generate code, Replay uses video input and behavior analysis to understand user intent, leading to more accurate and functional UI reconstruction. v0.dev typically relies on text prompts and may not capture the nuances of existing workflows. Replay is specifically designed for modernizing existing applications by understanding existing user behavior.

What frameworks does Replay support?#

Currently, Replay supports React, Vue, and Angular. We are constantly adding support for new frameworks.

How secure is Replay?#

Replay uses industry-standard security measures to protect your data. Video recordings are processed securely and are not shared with third parties.

Can I customize the generated code?#

Yes, the generated code is fully customizable. You can use it as a starting point and modify it to fit your specific needs.

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