How to Convert Figma Prototype Into A Next.js App With Authentication

TL;DR: Stop manually translating Figma prototypes into code; use Replay to automatically generate a Next.js app with authentication from a video walkthrough of your design.

The age of painstakingly converting Figma prototypes into functional code is OVER. While tools have emerged promising shortcuts, most fall short, merely offering static image-to-code conversions. This leaves developers wrestling with the crucial, yet tedious, work of implementing dynamic behavior, authentication, and backend integrations. Let's face it: a pretty picture doesn't equal a working application.

We're ushering in a new paradigm: behavior-driven reconstruction. Instead of relying on static screenshots, we leverage video analysis to understand how a user interacts with the prototype. This unlocks the ability to automatically generate not just the UI, but also the underlying logic and connections needed for a fully functional application.

This post will demonstrate how to use Replay to convert a Figma prototype into a working Next.js app with authentication, showcasing the power of video-to-code generation.

The Problem with Traditional Figma-to-Code Approaches#

Traditional Figma-to-code tools often rely on parsing the design file and generating code based on the visual elements. This approach has several limitations:

• •Static Output: They generate static HTML/CSS, lacking dynamic behavior or interactivity.
• •Missing Logic: They don't capture the intended user flow or application logic.
• •Limited Backend Integration: They offer little to no support for integrating with backend services like authentication.
• •Maintenance Overhead: The generated code often requires significant manual adjustments and maintenance.

Consider the following comparison:

Replay addresses these limitations by analyzing video recordings of users interacting with the Figma prototype. This allows Replay to understand the intended behavior and generate code that accurately reflects the desired functionality, including authentication and backend integrations.

Replay: Behavior-Driven Code Generation#

Replay takes a fundamentally different approach. It analyzes video recordings of users interacting with a Figma prototype to understand the intended behavior and generate code that accurately reflects the desired functionality.

Here's how it works:

1. •Record a Video: Record a video walkthrough of your Figma prototype, demonstrating the desired user flows and interactions, including the authentication process.
2. •Upload to Replay: Upload the video to the Replay platform.
3. •Replay Analyzes: Replay uses Gemini to analyze the video, identify UI elements, and understand the user's intent.
4. •Code Generation: Replay generates a Next.js application with authentication, including:
   • •UI components based on the Figma prototype.
   • •Navigation and routing based on the user flow in the video.
   • •Authentication logic using a backend like Supabase.
   • •Styles that closely match the original Figma design.

This process significantly reduces the manual effort required to convert a Figma prototype into a functional application.

Tutorial: Converting a Figma Prototype to a Next.js App with Authentication using Replay#

Let's walk through the steps to convert a Figma prototype into a functional Next.js application with authentication using Replay. We'll assume you have a Figma prototype with a login/signup flow and a protected area accessible only to authenticated users.

Step 1: Prepare Your Figma Prototype#

Ensure your Figma prototype has clear visual cues for the authentication flow. This includes:

• •Login and signup forms with input fields for email and password.
• •Buttons for submitting the forms.
• •A protected area (e.g., a dashboard) that is only accessible after successful login.

📝 Note: The more detailed and realistic your prototype, the better Replay can understand the intended behavior.

Step 2: Record a Video Walkthrough#

Record a video of you interacting with the Figma prototype. This video should demonstrate the following:

1. •Navigating to the signup page.
2. •Entering a valid email and password.
3. •Submitting the signup form.
4. •Navigating to the login page.
5. •Entering the same email and password.
6. •Submitting the login form.
7. •Accessing the protected area after successful login.
8. •Logging out.

Speak clearly while recording, narrating your actions. This helps Replay understand your intent. For example, say "Now I'm entering my email address" as you type.

Step 3: Upload the Video to Replay#

1. •Go to the Replay platform (https://replay.build).
2. •Create an account or log in.
3. •Click the "Upload Video" button.
4. •Select the video you recorded in Step 2.
5. •Give your project a name.

Step 4: Configure Authentication (Supabase Integration)#

Replay seamlessly integrates with Supabase for authentication. During the project setup, you'll be prompted to provide your Supabase API URL and API key.

1. •If you don't have a Supabase account, create one at https://supabase.com/.
2. •Create a new Supabase project.
3. •Retrieve your Supabase API URL and API key from the project settings.
4. •Enter the API URL and API key in the Replay project settings.

💡 Pro Tip: Ensure your Supabase project has the "Email/Password" authentication provider enabled.

Step 5: Generate the Next.js Application#

Once the video is uploaded and the Supabase configuration is complete, Replay will begin analyzing the video and generating the Next.js application. This process may take a few minutes, depending on the length of the video and the complexity of the prototype.

Step 6: Review and Customize the Generated Code#

After the code generation is complete, you can review and customize the generated code. Replay provides a code editor within the platform where you can make adjustments to the UI, logic, or styling.

The generated code will include:

• •Next.js components for each screen in the prototype.
• •Navigation logic based on the user flow in the video.
• •Authentication logic using the Supabase client library.
• •Styles that closely match the original Figma design.

Here's an example of the generated authentication code:

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

const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
const supabaseKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;

if (!supabaseUrl || !supabaseKey) {
  throw new Error('Supabase URL and Key are required');
}

const supabase = createClient(supabaseUrl, supabaseKey);

export default async function handler(req: any, res: any) {
  if (req.method === 'POST') {
    const { email, password } = req.body;

    try {
      const { data, error } = await supabase.auth.signInWithPassword({
        email,
        password,
      });

      if (error) {
        return res.status(401).json({ error: error.message });
      }

      return res.status(200).json({ user: data.user });
    } catch (error: any) {
      return res.status(500).json({ error: error.message });
    }
  } else {
    res.status(405).json({ message: 'Method Not Allowed' });
  }
}

This code snippet demonstrates how Replay automatically integrates with Supabase to handle user authentication.

Step 7: Deploy Your Application#

Once you are satisfied with the generated code, you can deploy your Next.js application to a hosting platform like Vercel or Netlify.

⚠️ Warning: Remember to configure your environment variables (Supabase API URL and API key) in your hosting platform.

Benefits of Using Replay#

• •Faster Development: Significantly reduces the time required to convert Figma prototypes into functional applications.
• •Improved Accuracy: Captures the intended user behavior and translates it into code.
• •Reduced Manual Effort: Automates the tedious tasks of implementing authentication and backend integrations.
• •Higher Quality Code: Generates clean, maintainable, and production-ready code.
• •Enhanced Collaboration: Facilitates collaboration between designers and developers by providing a shared understanding of the intended functionality.
• •Multi-Page Generation: Replay can generate code for multi-page applications, handling complex navigation flows.
• •Product Flow Maps: Automatically generates visual representations of user flows, making it easier to understand and optimize the application's usability.
• •Style Injection: Injects styles that closely match the original Figma design, preserving the visual fidelity of the prototype.

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. Check the pricing page for details.

How is Replay different from v0.dev?#

While both tools aim to accelerate UI development, Replay focuses on behavior-driven reconstruction using video input. v0.dev primarily relies on text prompts to generate UI components. Replay excels at capturing complex user flows and interactions, while v0.dev is better suited for generating individual components based on specific requirements.

What if Replay misinterprets something in my video?#

Replay provides a code editor where you can review and customize the generated code. You can easily correct any misinterpretations or make adjustments to the UI, logic, or styling. The more detailed and clear your video, the better Replay will understand your intent.

What other backend integrations does Replay support?#

Currently, Replay primarily supports Supabase for authentication. Support for other backend services is planned for future releases.

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