fonts.upset.dev

A privacy-preserving proxy for Google Fonts. It fetches font stylesheets and font files on behalf of visitors so their IP addresses and browser fingerprints are never sent to Google.

Features

• Proxies Google Fonts stylesheets and font files without exposing visitor IP addresses or browser fingerprints to Google.
• Rewrites font URLs in stylesheets to route through the proxy automatically.
• Minifies CSS stylesheets before serving them.
• Built-in cache via local disk to avoid redundant upstream requests.

How it works

When a browser requests a Google Fonts stylesheet through this proxy, the server:

1. Fetches the CSS from fonts.googleapis.com using a fixed user-agent string.
2. Minifies the CSS and rewrites all font file URLs to point back through the proxy.
3. Returns the rewritten stylesheet to the browser.

Font file requests (.woff2, etc.) are proxied directly from fonts.gstatic.com. In both cases, only a strict set of safe headers is forwarded so no cookies, IP addresses, or other user-identifying information ever reaches Google.

Usage

Replace your Google Fonts <link> tag with one pointing at this server. The path and query string stay the same.

Before:

<link
  rel="stylesheet"
  href="https://fonts.googleapis.com/css2?family=Inter:wght@400;700&display=swap"
/>

After:

<link
  rel="stylesheet"
  href="https://fonts.upset.dev/css2?family=Inter:wght@400;700&display=swap"
/>

That is all. Font files are automatically served through the proxy as well because the stylesheet URLs are rewritten server-side.

Running locally

Requirements: Go 1.24 or later

git clone https://github.com/fransallen/fonts.upset.dev
cd fonts.upset.dev
go run .

Run with Docker

docker run -d --name fonts.upset.dev -p 8080:8080 ghcr.io/fransallen/fonts.upset.dev

The server listens on http://localhost:8080.

Self-Hosting

fonts.upset.dev can be self-hosted using Docker or deployed to your preferred platform, like Fly, Render, or Railway.

Environment variables

Variable	Description	Default
CACHE_ENABLED	Set to true to enable the local disk cache	false
CACHE_DIR	Directory used to store cached CSS and font files	.fonts-cache

When the cache is enabled, responses include an X-Fonts-Cache header set to HIT or MISS.

Routes

Path	Description
/	Redirects to https://upset.dev/fonts
/css*	Proxies Google Fonts CSS stylesheets
/f/*	Proxies individual font files from fonts.gstatic.com

Privacy

This proxy is designed so that Google never sees your visitors:

• All requests to Google are made server-side with a fixed user-agent string.
• No request headers from the browser (IP, cookies, Referer, etc.) are forwarded.
• Only a safe subset of response headers is passed back to the browser.

Running tests

go test ./...

License

MIT