What are Client Hints? Differences Between Client Hints and User Agent

Key Relationship

Client Hints do not fully replace User Agent yet. Instead:

• Browsers now reduce UA detail
• Websites can optionally request specific information through Client Hints

Think of Client Hints as a more controlled, privacy-friendly evolution of the User-Agent mechanism.

Why Client Hints Matter (Real Use Cases)

Client Hints solve several real-world challenges:

1. Better Privacy with Less Data Exposure

Since browsers only send hints when requested, trackers cannot automatically extract device details.
This improves user privacy while still empowering websites with needed info.

2. More Accurate Device Detection

User-Agent strings often lie (for compatibility reasons).

Client Hints provide accurate, structured data directly from the browser.

3. Performance Optimization

Websites can adjust content delivery based on:

• Network speed
• Screen resolution
• Device capabilities

This ensures faster loading and better UX.

4. Reliable Multi-Device and Multi-Account Management

Privacy-focused users, automation tools, and multi-account platforms benefit from Client Hints because they reduce unnecessary fingerprinting vectors.

5. Future-Proofing

As major browsers roll out UA Reduction, developers need Client Hints to maintain compatibility and detection features.

Can Client Hints Be Spoofed?

Yes, Client Hints can be spoofed, but it's significantly more difficult than manipulating User-Agent strings.

Why are they harder to fake?

• Browsers validate the structure
• Servers must explicitly request hints
• Some hints depend on hardware (e.g., DPR, device model)
• Anti-detect tools must simulate multiple layers of environment data consistently

For ordinary scripts, spoofing Client Hints is not as simple as modifying a single header.

However…

Advanced tools—especially antidetect browsers used for marketing, e-commerce, or anti-tracking—can simulate real device environments, including Client Hints.
But this requires synchronized spoofing of:

• User Agent
• Client Hints headers
• JS-exposed properties
• Canvas/WebGL behavior
• Hardware metrics

If any detail is inconsistent, fingerprinting systems can still detect anomalies.

Fingerprint risk still exists. If a server requests multiple detailed ("high-entropy") hints at once, Client Hints can still form a highly unique fingerprint—sometimes even more structured than the old User-Agent string.

For example, combining these values:

// High-entropy Client Hints combined into a device fingerprint
const fingerprint = `${platform}_${platformVersion}_${architecture}_${model}_${deviceMemory}_${dpr}`;

Fingerprint Protection Recommendations

As web fingerprinting becomes more advanced, relying solely on Client Hints or UA spoofing is not enough. Here are practical, actionable tips:

1. Maintain Full Environment Consistency

Every fingerprinting vector—UA, Client Hints, canvas, fonts, WebRTC, timezone—must match one realistic device profile.

Random mismatches instantly trigger risk scores.

2. Avoid Manual Modifications

Editing headers manually often causes inconsistencies.
Instead, use automated browser profiles where the system generates coherent fingerprints.

3. Use Dynamic User Profiles

Static fingerprints reused across accounts can cause linking.
Rotate environment profiles periodically to avoid pattern detection.

4. Disable or Control WebRTC Leaks

Even if your UA and Client Hints are spoofed, a WebRTC IP leak can still expose your identity.

5. Keep Cookies and Storage Isolated

Client Hints do not protect against cookie tracking.
Each identity or account should have unique:

• Cookies
• Local storage
• Session storage

6. Use an Antidetect Browser for Multi-Account or Operational Tasks

Unlike simple extensions, anti-fingerprint browsers, e.g.: AdsPower, simulate consistent environments, including Client Hints and modern fingerprint surfaces.
This provides stronger protection against account linking and device recognition—especially important for:

• Marketing teams
• E-commerce sellers
• Web automation users
• Anti-ban operations
  

Final Thoughts

Client Hints are a major step forward for web privacy and performance. They offer a more precise, controlled alternative to the traditional User-Agent string, helping websites optimize content while reducing unnecessary data exposure.

However, Client Hints alone can't prevent fingerprinting. Real-world environments require consistent spoofing across all device surfaces—especially for users managing multiple accounts, safeguarding privacy, or avoiding unintended tracking.