Proxy Pattern Explained: How Next.js Apps Connect to AppEngine

The Proxy Pattern

The proxy pattern in Next.js allows you to route all API calls through your application, automatically handling authentication and token renewal.

How It Works

The /api/[...slug] route acts as a middleware that:

• Intercepts all API requests
• Adds authentication headers
• Forwards requests to AppEngine
• Handles token renewal automatically

Implementation

// app/api/[...slug]/route.ts
import { AppEngineClient } from '@/lib/appengine';

export async function GET(req, { params }) {
  const client = new AppEngineClient();
  return client.proxy(req, params.slug);
}

Benefits

• Secure credential management
• Automatic token handling
• Simplified API calls
• Built-in error handling