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Open-source fingerprint protection

VPNs hide where you are.
404 hides who you are.

Your browser fingerprint is as unique as a real one. 404 replaces it with a consistent, undetectable profile across TLS, HTTP, JavaScript, and TCP/IP surfaces.

How fingerprinting works
  • Open source
  • No accounts required
  • No data collection

The problem

You're being tracked in ways you can't see

Cookies are just the beginning. Modern tracking builds a unique profile from hundreds of signals your browser leaks on every page load. No cookies or logins required.

  • Your browser is unique

    Screen size, fonts, graphics card, audio processing, installed languages. Combined, they form a fingerprint more unique than your IP address. Commercial services can uniquely identify over 99% of browsers.

  • VPNs don't fix this

    A VPN hides your IP address. That's it. Your fingerprint is identical across VPN connections, incognito windows, and different networks. Trackers reconnect you instantly.

  • They already know it's you

    Commercial fingerprinting services identify users across browsers, devices, and sessions. They link private browsing to your public profile. Clearing cookies changes nothing.

How it works

Three steps to disappear

No browser extensions. No cloud service. 404 runs locally on your machine and rewrites your fingerprint at every layer of the network stack.

  1. Install

    One command to build from source, or download the desktop app. 404 runs as a local proxy. Your traffic never leaves your machine unprotected.

    cargo run Rust · open source · AGPL

  2. Choose a profile

    Select a browser profile — Chrome on Windows, Firefox on macOS, or build your own. 404 applies it consistently across TLS handshakes, HTTP headers, JavaScript APIs, and TCP/IP packet signatures.

    TLS · HTTP · JS · TCP/IP

  3. Browse

    That's it. Your fingerprint now matches thousands of other users running the same profile. Trackers see a crowd, not an individual.

    See the technical details

No accounts. No telemetry. No data leaves your machine.

View on GitHub Read the docs

Who it's for

Built for people, not bots

Anti-detect browsers are built for web scraping and automation. 404 is built for people with real reasons to protect their identity online.

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. A privacy tool that requires trust isn't a privacy tool.

Source code Documentation

Verify it yourself

FingerprintJS passing BrowserLeaks passing EFF Cover Your Tracks passing CreepJS passing

Ready to disappear?

Join the waitlist for early access. We'll let you know when 404 is ready for your platform.

No spam. No tracking. Delivered via Proton Mail.

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