A Comprehensive Guide to Dynamic Private Environment Variables in SvelteKit

This guide provides a detailed overview of how to effectively use dynamic private environment variables in SvelteKit applications, ensuring the security and integrity of sensitive data.

Key Concepts

• Environment Variables: Variables that can be set outside your application, accessed within your code, and often used to store sensitive information like API keys or database credentials.
• Dynamic Variables: Unlike static environment variables defined at build time, dynamic variables can change while the application is running.
• Private Variables: Variables that should not be exposed to client-side code for security reasons.

Setting Up Environment Variables

1. Create a .env File:
   • Place your environment variables in a file named .env at the root of your project.
   • Example:
2. Accessing Environment Variables:
   • Use import.meta.env to access environment variables in your SvelteKit application.
   • Example:

const apiKey = import.meta.env.VITE_MY_PRIVATE_API_KEY;

MY_PRIVATE_API_KEY=secret_value

Dynamic Private Variables

• Server-Side Access: Access private environment variables only on the server side, ensuring they remain hidden from the client.
• Creating an Endpoint:
  • To expose server data to the client without revealing private keys, create an API endpoint in your SvelteKit application.
  • Example:
• Fetching Data:
  • Use the created endpoint in your Svelte components to fetch data without exposing sensitive information.
  • Example:

const response = await fetch('/api/data');
const data = await response.json();
console.log(data.secretValue); // Access secret value on client-side securely

// src/routes/api/data.js
export async function get() {
  const secretValue = process.env.MY_PRIVATE_API_KEY; // Accessing private variable
  return {
    body: { secretValue }
  };
}

Important Notes

• Security: Always ensure your private environment variables are not included in the client-side bundle. Use server-side logic to manage sensitive data.
• VITE Prefix: In SvelteKit, only variables prefixed with VITE_ are exposed to the client. Use this convention for any environment variables you want to make public.

Conclusion

Using dynamic private environment variables in SvelteKit allows developers to manage sensitive data securely while providing necessary functionality to the client-side. Always remember to handle private data responsibly to protect your application's integrity.