What Is CreepJS?

CreepJS is a browser fingerprinting tool designed to measure how uniquely identifiable a device is based on the information exposed by the browser. It collects detailed technical data—such as hardware characteristics, rendering behavior, and supported APIs—to determine how easily a website can track a user without cookies.

Unlike simple fingerprint tests, CreepJS performs deep, advanced checks that reveal subtle inconsistencies, spoofed values, and entropy levels. It is often used for privacy analysis, research, and testing anti-tracking tools.

What CreepJS Measures

CreepJS performs a wide range of fingerprinting tests, including:

1. Canvas Fingerprinting

Analyzes how the browser renders shapes and text in a <canvas> element. Even tiny rendering differences create a unique signature.

2. WebGL Fingerprinting

Detects GPU model behavior, driver variations, and graphics features based on rendering output.

3. Audio Fingerprinting

Uses the Web Audio API to determine unique processing characteristics of the device.

4. User Agent & Navigator Data

Collects browser version, platform details, CPU info, and device memory.

5. Screen & Display Characteristics

Includes screen size, color depth, pixel ratio, and available resolutions.

6. Timezone & Locale

Detects system clock offset, language, and regional formatting behavior.

7. Fonts, Emojis & Text Rendering

Measures font availability and glyph rendering differences.

8. Permissions API & Feature Detection

Reveals which browser capabilities are enabled or blocked.

In combination, these data points create a highly detailed device fingerprint.

Why People Use CreepJS

Privacy Testing

Users check how identifiable their browser is and whether anti-tracking tools (VPNs, extensions, hardened browsers) work effectively.

Developer Research

Developers use CreepJS to understand which browser properties can leak unique data and how to minimize exposure.

Security Analysis

Security teams test how easily devices can be profiled or linked across sessions.

Browser Hardening

Privacy-focused users test different setups:

• Firefox hardened profiles
• Safari’s anti-tracking
• Brave’s fingerprinting protection
• Tor Browser configurations

CreepJS helps measure how successful these protections are.

What Makes CreepJS Different from Other Fingerprinting Tests?

✅ More Detailed Measurements

CreepJS performs deeper, more granular tests than typical fingerprinting checkers.

✅ Calculates Entropy & Uniqueness

It doesn’t just collect data — it shows how unique each value is.

✅ Detects Spoofing & Inconsistent Values

If your browser tries to fake its identity, CreepJS often reveals mismatches.

✅ Focuses on Modern APIs

It evaluates newer fingerprint vectors such as:

• OffscreenCanvas
• WebGPU (in supporting browsers)
• Navigator properties changed by privacy tools

✅ Visual Output

Many results are displayed as fingerprint hashes or entropy graphs.

What CreepJS Results Mean

CreepJS typically shows:

• How identifiable you are (low, medium, or high uniqueness)
• Which APIs leak the most information
• Whether your fingerprint is stable across page reloads
• How vulnerable your setup is to cross-site tracking
• Which protections work and which fail

A “high entropy” output means your device is extremely unique and easily trackable.

How to Reduce Fingerprinting Detected by CreepJS

✅ Use a privacy-focused browser

Browsers like Tor and Brave offer built-in fingerprint resistance.

✅ Standardize your browser configuration

The more “normal” your setup is, the less unique you appear.

✅ Block or limit JavaScript

Most fingerprint methods require JavaScript to run.

✅ Avoid rare screen sizes or unusual hardware

Unique hardware often produces unique fingerprints.

✅ Use containerized or disposable browser sessions

Reduces the long-term stability of your fingerprint.

When Not to Use Fingerprinting Tools

Avoid using CreepJS or similar tools in environments where:

• Corporate IT policies restrict browser testing
• You are using sensitive accounts
• JavaScript-heavy fingerprint pages may cause performance issues

Fingerprinting tests should be used in controlled or personal environments only.

Conclusion

CreepJS is a powerful fingerprinting analysis tool that reveals how identifiable a browser truly is. Whether you're a privacy researcher, developer, or security analyst, CreepJS highlights how modern browsers expose technical details that tracking systems can exploit. Understanding its results helps users strengthen privacy protections and reduce their online fingerprint.