How to Convert a Video of a Web App into a Next.js App with SSR using Replay AI

TL;DR: Replay AI reconstructs fully functional Next.js applications with server-side rendering (SSR) directly from screen recordings of user interactions, enabling rapid prototyping and UI replication.

Stop Mocking, Start Replaying: From Video to SSR Next.js App#

Building UIs is hard. Replicating existing ones, pixel-perfect and functionally accurate, is even harder. Screenshot-to-code tools offer a superficial representation, but they miss the crucial element: user behavior. What if you could capture the intent behind the UI, not just its appearance?

Enter Replay. Replay leverages Gemini to understand user flows from video recordings and automatically reconstruct working UI code, including handling multi-page applications, data integration, and even styling. This isn't just about generating static components; it's about capturing the dynamic behavior of a web app.

Why Video-to-Code?#

Traditional methods of UI replication are time-consuming and error-prone. Manual coding based on visual inspection often leads to inconsistencies and missed interactions. Screenshot-to-code tools offer a faster approach, but they fall short when dealing with dynamic content, complex user flows, and data interactions.

Replay bridges the gap by analyzing video recordings of user interactions. This allows it to:

• •Understand user intent by observing clicks, scrolls, and form submissions.
• •Reconstruct complex multi-page applications with accurate navigation.
• •Integrate with backend services like Supabase to handle data fetching and persistence.
• •Inject styles based on the observed UI, ensuring visual fidelity.

Building a Next.js App with SSR from a Video: A Step-by-Step Guide#

Let's walk through the process of converting a video of a web application into a functional Next.js application with server-side rendering using Replay.

Step 1: Recording the Video#

The first step is to create a clear and comprehensive video recording of the web application you want to replicate.

💡 Pro Tip: Ensure the video captures all relevant user interactions, including navigation, form submissions, and data updates. A clear voiceover explaining the intended behavior can also significantly improve accuracy.

Step 2: Uploading to Replay#

Once you have your video, upload it to the Replay platform. Replay will automatically analyze the video, identify UI elements, and infer user behavior.

Step 3: Configuring the Project#

After uploading, you'll be prompted to configure your project. This includes:

• •Project Name: A descriptive name for your project.
• •Framework: Select "Next.js" as the target framework.
• •Rendering: Choose "Server-Side Rendering (SSR)".
• •Supabase Integration: If your application uses Supabase, provide your Supabase URL and API key.

⚠️ Warning: Ensure your Supabase credentials are secure and only grant necessary permissions.

Step 4: Reviewing the Generated Code#

Replay will generate a complete Next.js application based on the video analysis. This includes:

• •Page Components: React components for each page in the application.
• •API Routes: API routes for handling data fetching and persistence.
• •Styles: CSS or Tailwind CSS styles to match the original UI.
• •Navigation: Navigation links between pages.

Review the generated code to ensure accuracy and make any necessary adjustments.

Step 5: Deploying the Application#

Once you're satisfied with the generated code, you can deploy the application to your preferred hosting provider (Vercel, Netlify, etc.).

Diving Deeper: Code Examples and Implementation Details#

Let's examine some code snippets that illustrate how Replay handles specific aspects of the application reconstruction process.

SSR Data Fetching#

Replay automatically generates

functions to fetch data on the server for SSR.

typescript
// pages/index.tsx
import { GetServerSideProps } from 'next';

interface Props {
  data: any[];
}

export const getServerSideProps: GetServerSideProps<Props> = async () => {
  const res = await fetch('https://your-api-endpoint.com/data');
  const data = await res.json();

  return {
    props: {
      data,
    },
  };
};

const HomePage: React.FC<Props> = ({ data }) => {
  return (
    <div>
      <h1>Data from Server</h1>
      <ul>
        {data.map(item => (
          <li key={item.id}>{item.name}</li>
        ))}
      </ul>
    </div>
  );
};

export default HomePage;

This code fetches data from an API endpoint during server-side rendering, ensuring that the page is fully populated with content before being sent to the client.

Supabase Integration#

If you've configured Supabase integration, Replay will generate code that uses the Supabase client to interact with your database.

typescript
// pages/api/todos.ts
import { createClient } from '@supabase/supabase-js';
import type { NextApiRequest, NextApiResponse } from 'next';

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: NextApiRequest, res: NextApiResponse) {
  if (req.method === 'POST') {
    const { task } = req.body;
    const { data, error } = await supabase
      .from('todos')
      .insert([{ task }])
      .select();

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

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

This API route demonstrates how to insert data into a Supabase table using the Supabase client. Replay automatically infers the necessary database schema and generates the corresponding code.

Replay: More Than Just Code Generation#

Replay goes beyond simple code generation by providing a comprehensive understanding of user behavior. This allows it to create applications that are not only visually accurate but also functionally correct.

• •Behavior-Driven Reconstruction: Replay analyzes user interactions to understand the intent behind the UI, not just its appearance.
• •Multi-Page Generation: Replay seamlessly handles multi-page applications, capturing navigation and data flow between pages.
• •Supabase Integration: Replay automatically integrates with Supabase to handle data fetching and persistence, reducing the need for manual coding.
• •Style Injection: Replay injects styles based on the observed UI, ensuring visual fidelity.
• •Product Flow Maps: Visual representation of user flows for easier debugging and modification.

📝 Note: Replay's ability to analyze video recordings and infer user behavior sets it apart from traditional screenshot-to-code tools. This allows it to create applications that are more accurate, functional, and maintainable.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features. Paid plans are available for more advanced features and higher usage limits. Check the Replay pricing page for the most up-to-date information.

How is Replay different from v0.dev?#

While v0.dev focuses on generating UI components from text prompts, Replay analyzes video recordings to understand user behavior and reconstruct complete applications. Replay excels at replicating existing UIs and capturing complex user flows. v0.dev focuses on creating new UIs from scratch using AI.

What types of applications can Replay reconstruct?#

Replay can reconstruct a wide range of web applications, including e-commerce sites, dashboards, and social media platforms. The complexity of the application will affect the accuracy and completeness of the generated code.

What video formats are supported?#

Replay supports common video formats such as MP4, MOV, and AVI.

How accurate is the generated code?#

The accuracy of the generated code depends on the quality of the video recording and the complexity of the application. Replay uses advanced AI algorithms to maximize accuracy, but manual review and adjustments may be necessary.

Can I customize the generated code?#

Yes, the generated code is fully customizable. You can modify the code to add new features, change the UI, or integrate with other services.

Does Replay support other backend services besides Supabase?#

Currently, Replay has native integration with Supabase. Support for other backend services is planned for future releases. You can always manually integrate other backend services into the generated code.

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Ready to try behavior-driven code generation? Get started with Replay - transform any video into working code in seconds.