Replay for building e-commerce apps from UI video: A 2026 Step-by-Step Guide

TL;DR: Build fully functional e-commerce applications from video recordings of user flows using Replay's behavior-driven code generation, saving development time and ensuring accurate representation of user intent.

The year is 2026. Traditional hand-coding for e-commerce apps feels… archaic. Customers demand seamless, intuitive experiences, and capturing that essence in code is notoriously difficult. Forget static mockups – the future is behavior. What if you could simply record a user interacting with a desired UI and instantly generate production-ready code? That future is here, powered by Replay.

Replay: Behavior-Driven E-commerce Development#

Replay isn't just another screenshot-to-code tool. It's a video-to-code engine that leverages advanced AI (powered by Gemini) to understand user behavior and reconstruct fully functional UIs. This "Behavior-Driven Reconstruction" uses the video as the single source of truth, ensuring the generated code accurately reflects the intended user experience.

Why Video Matters#

Static designs often fail to capture the nuances of user interaction. Think about subtle animations, micro-interactions, or complex form flows. These details are crucial for a positive user experience, but they're often lost in translation when moving from design to code. Replay solves this by analyzing video, understanding the sequence of events, and generating code that replicates the observed behavior.

Consider the alternatives:

Replay stands out by directly capturing and translating user intent into working code, significantly reducing development time and minimizing the risk of misinterpretation.

Building an E-commerce App with Replay: A Step-by-Step Guide (2026)#

Let's walk through building a simplified e-commerce app – a product listing page with a shopping cart – using Replay.

Step 1: Record the User Flow#

First, record a video of yourself (or a user) interacting with a reference e-commerce UI. This could be an existing app, a prototype, or even a whiteboard sketch brought to life with basic interactions. The key is to capture the flow:

1. •Browsing products
2. •Adding items to the cart
3. •Viewing the cart
4. •(Optional) Proceeding to checkout (we'll simplify this for now)

💡 Pro Tip: Ensure the video is clear and stable. Narrate the actions you're performing to provide additional context for Replay.

Step 2: Upload to Replay#

Upload the video to the Replay platform. Replay’s AI engine will then analyze the video, identify UI elements, and understand the relationships between them.

📝 Note: Replay supports various video formats and resolutions. Check the documentation for the optimal settings.

Step 3: Code Generation and Review#

Replay generates the code based on its analysis. This includes:

• •HTML structure
• •CSS styling
• •JavaScript logic for interactions (e.g., adding to cart, updating quantities)

You can then review the generated code within the Replay interface.

⚠️ Warning: While Replay strives for accuracy, manual review is always recommended, especially for complex applications.

Step 4: Supabase Integration (Backend)#

Replay seamlessly integrates with Supabase for backend functionality. You'll need a Supabase project set up with tables for:

• •
  text

  products
  (id, name, description, price, image_url)
• •
  text

  cart_items
  (id, user_id, product_id, quantity)

Replay can automatically generate API endpoints to interact with your Supabase database. You can configure these endpoints within the Replay interface, specifying the data to fetch and the actions to perform.

Here's an example of a generated API endpoint (using Next.js API routes):

typescript
// pages/api/products.ts
import { createClient } from '@supabase/supabase-js';

const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
const supabaseKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
const supabase = createClient(supabaseUrl, supabaseKey);

export default async function handler(req: any, res: any) {
  if (req.method === 'GET') {
    const { data, error } = await supabase
      .from('products')
      .select('*');

    if (error) {
      return res.status(500).json({ error: error.message });
    }

    return res.status(200).json(data);
  } else {
    res.status(405).json({ message: 'Method Not Allowed' });
  }
}

This code fetches all products from the

table in Supabase. Replay can generate similar endpoints for adding items to the cart, retrieving cart contents, and updating quantities.

Step 5: Style Injection#

Replay allows you to inject custom styles to fine-tune the appearance of your e-commerce app. You can either write CSS directly within the Replay interface or import existing stylesheets. This ensures that the generated UI aligns with your brand's visual identity.

Step 6: Product Flow Maps#

Replay automatically generates "Product Flow Maps" based on the video analysis. These maps visually represent the user's journey through the application, highlighting key interactions and transitions. This is invaluable for understanding user behavior and identifying potential areas for improvement.

Here's a simplified example of a Product Flow Map:

text
[Start] --> [Browse Products] --> [Add to Cart] --> [View Cart] --> [End]

Replay can generate much more detailed maps, including information about time spent on each screen, the frequency of specific actions, and potential drop-off points.

Replay's Unique Advantages#

• •Multi-Page Generation: Replay can handle multi-page applications, capturing complex user flows that span multiple screens.
• •Behavior-Driven Reconstruction: Unlike screenshot-to-code tools, Replay understands what users are trying to do, not just what they see.
• •Supabase Integration: Seamlessly connect your generated UI to a powerful backend.
• •Style Injection: Customize the appearance of your app with ease.
• •Product Flow Maps: Gain valuable insights into user behavior.

Addressing Common Concerns#

• •Accuracy: Replay's accuracy depends on the quality of the input video. Clear, stable videos with well-defined user flows yield the best results. Manual review is always recommended.
• •Complexity: Replay excels at generating code for common UI patterns and interactions. Highly complex or custom components may require additional manual coding.
• •Customization: While Replay provides a solid foundation, you'll likely need to customize the generated code to meet your specific requirements. Style injection and component modification are key to this process.

Comparison with Other Tools#

Replay distinguishes itself through its unique video-to-code approach, behavior analysis, and seamless Supabase integration.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a freemium model. The free tier provides limited usage, while paid plans unlock advanced features and higher usage limits.

How is Replay different from v0.dev?#

v0.dev primarily uses text prompts to generate UI components. Replay, on the other hand, uses video analysis to understand user behavior and reconstruct entire applications, capturing the nuances of user interaction that text prompts often miss. Replay focuses on behavior-driven development, while v0.dev focuses on prompt-driven generation.

What types of e-commerce applications can I build with Replay?#

Replay is suitable for building a wide range of e-commerce applications, including product listing pages, shopping carts, checkout flows, user profiles, and order management systems. The complexity of the application will determine the amount of manual customization required.

What if the video quality is poor?#

Poor video quality can negatively impact Replay's accuracy. Ensure the video is clear, stable, and well-lit. Consider re-recording the video if necessary.

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