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Reclaim Your Digital Anonymity

Local by design. Illegibility on purpose.

v1.1 available

New builds are live. If you’re upgrading, skim the release notes before swapping profiles.

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Core capabilities

sequenceDiagram
    participant F as Alice
    participant 404
    participant A as Ad-Tech Corporations
    F->>404: Hi, Google! I am using Firefox on Windows
    404->>A: Hi, Google! I am using Chrome on macOS
    A->>404: Hi, Alice! Here is your webpage for Chrome on macOS.
    404->>F: Here is your webpage.

  • Anti-fingerprinting

    404 targets correlation: offers coherent profiles across TLS → headers → JS surfaces.

  • Cross-platform

    Written in Rust for Windows, macOS, Linux. Run locally, keep control locally.

  • Open source

    Full transparency.

The leakage problem

Your browser is telling ad-tech corporations too much.

Websites and fingerprinting vendors collect semi-unique signals and combine them into a “personality cloud”:

  • Canvas and text rendering quirks
  • WebGL parameters and GPU hints
  • Audio context characteristics
  • Fonts and device enumeration
  • Locale/timezone/screen geometry
  • TLS and header shapes
  • Typing speed

404 sits in the middle and rewrites your fingerprint before it leaves your machine.

What 404 changes

  • TLS Fingerprint

    404 controls handshake behavior as a profile decision: extensions, ordering, ALPN, key shares, and cipher preferences are defined in the profile.

    Note

    TLS impersonation fidelity is adversarial and evolving. The goal is plausible identity.

  • Network Telemetry

    Rewrites TCP/IP options such as MSS, Window Size/Scale, TTL, and more. These values can be passively collected and used to offer details on your network stack. Tools like nmap and p0f exploit these network telemetry signals to identify your hardware, OS, network environment, and more.

  • HTTPS Headers

    Normalizes and rewrites headers and header ordering to match the chosen persona.

    • Consistent User-Agent + client hints
    • Language/timezone coherence
    • Optional downgrades/strips to reduce leak paths (e.g., Alt-Svc preventing accidental HTTP/3/QUIC identity drift)

  • JavaScript Fingerprint Surfaces

    Injects a profile-driven spoofing layer (canvas/WebGL/audio/fonts/media devices, etc.) while keeping the identity coherent.

    Tip

    Coherence beats randomness. Random noise is how you become a rare, clusterable outlier.