Skip to main content

This is 404

Websites can still track you, even with a VPN.

Your browser remembers what you shop for, who you talk to, and where you go online. 404 is a local proxy that stops websites from building a fingerprint of your browser and tracking you across the web.

You're not as private as you think.

How 404 stops trackers
  • Open source
  • No accounts required
  • No data collection
Get 404 Learn more

The problem

How you're identified online

99%

Commercial services can uniquely identify over 99% of browsers.

Screen size, fonts, graphics hardware, audio processing, installed languages. Combined, they form a fingerprint more precise than your IP address. Cookies and logins are not required. Your browser emits enough detail on its own.

VPNs mask your IP address. That's a real benefit, but it's one signal out of hundreds. Your fingerprint is identical whether you're on a VPN, in incognito mode, or on a different network. The IP changes. Everything else stays the same.

Services like FingerprintJS are built specifically to identify browsers across sessions and devices. They're used by fraud detection systems, advertising platforms, and analytics providers. The technology is mature, widely deployed, and works regardless of whether you've cleared your cookies.

How it works

A local proxy. No cloud. No extensions.

404 runs locally between your browser and the sites you visit. It rewrites the fingerprinting signals exposed across TLS, HTTP, JavaScript, and TCP/IP, then applies them consistently for that session so the next one has no connection to the last.

Get the desktop app

The fastest way to get started. Download the app, install the local certificate, and point your browser at the proxy. Profiles are managed through the interface. No terminal required.

See pricing

Desktop app · Managed updates · Monthly subscription

Self-host it

404 is open source under the AGPL. Run it yourself, build from source, and manage your own profiles. Full documentation covers installation and configuration.

Read the docs

Rust · Open source · AGPL

No accounts. No telemetry. No data leaves your machine. See the full architecture

Who it's for

Built for work where exposure has consequences.

404 is for people whose browser identity can expose research, clients, sources, or staff.

Open source

Don't trust us. Verify.

404 is open source under the AGPL license. Every line of code is auditable. We don't collect data, we don't phone home, and we don't require accounts. It's browser fingerprint protection software you can inspect yourself. A privacy tool that requires trust isn't a privacy tool.

Source code Documentation

Verify it yourself

FingerprintJS Visit BrowserLeaks Visit EFF Cover Your Tracks Visit CreepJS Visit

404 Blog

Stay up to date on the latest privacy trends

Read the blog See pricing

Need rollout, support, or pricing details instead? honda@404privacy.com

GitHub Docs Discord Contact