Next.js Font Optimization Error Fix

In this tutorial, you'll learn about Next.js Font Optimization Error Fix. We cover key concepts, practical examples, and best practices.

The Problem

Error: Failed to load font from Google Fonts. Check the URL and try again.

next/font cannot fetch the Google Font URL due to network issues or invalid font name.

Wrong

import { Inter } from 'next/font/google'

const inter = Inter({ subsets: ['latin'] })

Output: error if the font name is misspelled or the subset is incorrect.

Right

import { Inter } from 'next/font/google'

const inter = Inter({
  subsets: ['latin'],
  weight: ['400', '700'],
  display: 'swap',
})

export default function Home() {
  return (
    <main className={inter.className}>
      <h1>Hello World</h1>
    </main>
  )
}

Expected output: page uses Inter font with fallback display: swap.

For local fonts:

import localFont from 'next/font/local'

const myFont = localFont({
  src: './my-font.woff2',
  display: 'swap',
})

Prevention

• Verify font names against Google Fonts catalog
• Specify the correct CSS display value (usually swap)
• Use local fonts for production to eliminate external requests

Common Mistakes with font optimization

1. Using foldl instead of foldl' causing stack overflow on large lists
2. Forgetting deriving (Show, Eq) on custom data types needed for debugging
3. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable

These mistakes appear frequently in real-world NEXTJS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ