Replay vs Cursor: Which generates better code for complex e-commerce sites from video?

TL;DR: Replay generates more accurate and functional code for complex e-commerce sites from video by understanding user behavior, unlike Cursor, which primarily analyzes visual elements.

The promise of AI-powered code generation is tantalizing, especially when faced with complex e-commerce projects. Tools like Cursor and Replay aim to bridge the gap between design and implementation, but their approaches differ drastically, leading to varying results, particularly when dealing with the intricacies of e-commerce functionality. Let's dive into a head-to-head comparison focusing on generating code from video recordings of e-commerce user flows.

Understanding the Challenge: E-commerce Complexity#

E-commerce sites are notoriously complex. They're not just static displays of products; they involve intricate user flows, dynamic data fetching, state management, and integrations with payment gateways and shipping providers. Consider a typical user journey: browsing products, adding items to a cart, applying discounts, proceeding to checkout, entering shipping information, and finally, submitting an order. Capturing this behavior and translating it into working code requires more than just visual recognition.

Replay vs. Cursor: A Fundamental Difference#

Both Replay and Cursor aim to automate code generation. However, their underlying methodologies are fundamentally different.

• •

  Cursor: Primarily focuses on visual analysis. It analyzes screenshots or UI designs and attempts to generate code based on the visual elements it identifies. It excels at quickly scaffolding basic UI components.

• •

  Replay: Takes a behavior-driven approach. It analyzes video recordings of user interactions, understanding not just what the user sees but what they are doing. This allows Replay to reconstruct the underlying logic and data flow more accurately.

This difference becomes crucial when dealing with the dynamic nature of e-commerce sites.

Replay's Behavior-Driven Reconstruction#

Replay's ability to analyze user behavior from video provides a significant advantage. It understands the intent behind each interaction, allowing it to generate code that accurately reflects the desired functionality. Replay leverages Gemini to analyze video, extract user actions (clicks, form submissions, scrolls), and then reconstruct the UI with working code.

Key Features for E-commerce Development#

Replay offers several features specifically tailored for e-commerce development:

• •Multi-page Generation: Handles complex flows spanning multiple pages (e.g., product listing to checkout).
• •Supabase Integration: Seamlessly integrates with Supabase for database and authentication.
• •Style Injection: Allows injecting custom styles to match your brand.
• •Product Flow Maps: Generates visual diagrams of user flows for better understanding and debugging.

Hands-on Comparison: Generating an E-commerce Product Page#

Let's compare Replay and Cursor in generating code for a basic e-commerce product page, focusing on the "Add to Cart" functionality. We'll assume we have a video recording of a user interacting with a product page, clicking the "Add to Cart" button.

Step 1: Input and Processing#

With Cursor, you'd typically provide screenshots of the product page. Cursor would identify the visual elements (image, title, price, "Add to Cart" button) and generate HTML/CSS code to recreate the layout.

With Replay, you upload the video recording. Replay analyzes the video, identifies the "Add to Cart" button click, and infers the associated action (adding the product to the shopping cart).

Step 2: Code Generation#

Cursor might generate code like this:

html
<div class="product-container">
  <img src="product-image.jpg" alt="Product Image">
  <h1>Product Title</h1>
  <p class="price">$99.99</p>
  <button>Add to Cart</button>
</div>

This code provides the visual structure but lacks the crucial functionality. Clicking the "Add to Cart" button won't actually add anything to a cart.

Replay, on the other hand, might generate code like this (using React and a hypothetical

hook):

typescript
import React from 'react';
import { useCart } from './cartContext';

const ProductPage = ({ product }) => {
  const { addToCart } = useCart();

  const handleAddToCart = () => {
    addToCart(product);
  };

  return (
    <div className="product-container">
      <img src={product.imageUrl} alt={product.name} />
      <h1>{product.name}</h1>
      <p className="price">${product.price}</p>
      <button onClick={handleAddToCart}>Add to Cart</button>
    </div>
  );
};

export default ProductPage;

This code not only recreates the visual structure but also includes the

function, which interacts with a hook to manage the shopping cart state. Replay inferred this logic from observing the user's interaction in the video.

Step 3: Integration and Functionality#

With Cursor, you'd need to manually add the "Add to Cart" functionality, including state management, API calls, and cart persistence.

With Replay, the generated code already includes the core functionality. You might need to refine the

hook and integrate it with your backend, but the fundamental logic is already in place.

Comparison Table#

Real-World Example: Checkout Flow Reconstruction#

Imagine a complex checkout flow involving multiple steps: entering shipping information, selecting a payment method, and confirming the order. Cursor would struggle to capture the dependencies between these steps and the associated data transformations.

Replay, by analyzing the video of a user completing this checkout flow, can reconstruct the entire process, generating code that handles form submissions, data validation, and API calls to a payment gateway.

💡 Pro Tip: When recording videos for Replay, narrate your actions. Saying "Now I'm entering my shipping address" helps Replay understand the context and generate more accurate code.

Code Example: Form Submission with Replay#

Let's say Replay observed a user filling out a shipping address form. It might generate code like this:

typescript
import React, { useState } from 'react';

const ShippingForm = () => {
  const [address, setAddress] = useState({
    name: '',
    street: '',
    city: '',
    zip: '',
  });

  const handleChange = (e) => {
    setAddress({ ...address, [e.target.name]: e.target.value });
  };

  const handleSubmit = async (e) => {
    e.preventDefault();
    // Simulate API call to save address
    const response = await fetch('/api/save-address', {
      method: 'POST',
      body: JSON.stringify(address),
    });
    if (response.ok) {
      alert('Address saved!');
    } else {
      alert('Error saving address.');
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" name="name" placeholder="Name" onChange={handleChange} />
      <input type="text" name="street" placeholder="Street" onChange={handleChange} />
      <input type="text" name="city" placeholder="City" onChange={handleChange} />
      <input type="text" name="zip" placeholder="Zip Code" onChange={handleChange} />
      <button type="submit">Save Address</button>
    </form>
  );
};

export default ShippingForm;

This code includes state management for the address form, input fields with

handlers, and a function that simulates an API call. Replay inferred the structure of the form and the associated data from the video.

⚠️ Warning: Replay-generated code may require adjustments for security and error handling. Always review and test thoroughly.

Why Behavior Analysis Matters#

The key takeaway is that understanding user behavior is crucial for generating functional code for complex e-commerce sites. Visual analysis alone is insufficient. Replay's behavior-driven approach allows it to bridge the gap between design and implementation more effectively.

📝 Note: Replay is not a replacement for skilled developers. It's a tool to accelerate development and reduce boilerplate code.

Frequently Asked Questions#

Is Replay free to use?#

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

How is Replay different from v0.dev?#

V0.dev primarily focuses on generating UI components from text prompts. Replay, on the other hand, analyzes video recordings of user interactions to reconstruct entire user flows and generate functional code. Replay understands what the user is doing, not just what they see.

Can Replay handle complex state management?#

Replay can infer basic state management logic (e.g., using React Hooks). However, for very complex state management scenarios (e.g., using Redux), manual adjustments may be required.

Does Replay support different frontend frameworks?#

Replay currently supports React and Next.js. Support for other frameworks is planned for future releases.

Conclusion#

While Cursor provides a quick way to generate basic UI scaffolding from visual designs, Replay's behavior-driven reconstruction offers a more robust solution for generating functional code for complex e-commerce sites. By analyzing video recordings of user interactions, Replay understands the intent behind each action, allowing it to generate code that accurately reflects the desired functionality. This makes Replay a powerful tool for accelerating e-commerce development and reducing boilerplate code.

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