What are HTTP Client Hints?

HTTP Client Hints are a set of request headers that browsers can send to servers to share information about the device, operating system, browser, and network conditions. Unlike the traditional User-Agent string — which packs all information into a single opaque string — Client Hints are structured, individual headers that make it easier to extract specific details without complex string parsing.

Client Hints were introduced as part of the W3C specification and are now supported by Chromium-based browsers (Chrome, Edge, Opera). They fall into two categories: low-entropy hints (like Sec-CH-UA and Sec-CH-UA-Mobile) sent automatically, and high-entropy hints (like Sec-CH-UA-Platform-Version, Sec-CH-UA-Arch, and Sec-CH-UA-Bitness) that require explicit permission via an Accept-CH response header.

Tool description

This tool parses HTTP Client Hints headers and the classic User-Agent string to extract structured information about the browser, operating system, device, CPU architecture, and rendering engine. You can enter hints manually as individual fields, paste raw HTTP headers all at once, or click "Detect from browser" to automatically capture the hints your current browser exposes.

Examples

Input (raw headers):

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36
Sec-CH-UA: "Chromium";v="124", "Google Chrome";v="124", "Not-A.Brand";v="99"
Sec-CH-UA-Mobile: ?0
Sec-CH-UA-Platform: "Windows"
Sec-CH-UA-Platform-Version: "15.0.0"
Sec-CH-UA-Arch: "x86"
Sec-CH-UA-Bitness: "64"
Sec-CH-UA-Model: ""
Sec-CH-UA-Full-Version-List: "Chromium";v="124.0.6367.62", "Google Chrome";v="124.0.6367.62"
Sec-CH-UA-Form-Factors: "Desktop"

Output:

Field Value
Browser Google Chrome 124.0.6367.62
Browser Engine Blink
OS Windows 15.0.0
Architecture x86 / 64-bit
Device Type Desktop
Mobile No

Features

  • Auto-detect from browser: Reads User-Agent and requests high-entropy Client Hints directly from your current browser with a single click
  • Two input modes: Enter hints as individual labeled fields, or paste a raw HTTP header block and let the tool parse the key-value pairs automatically
  • Full hint coverage: Supports all standard Sec-CH-UA-* headers including platform version, architecture, bitness, device model, full version list, and form factors

Options explained

Field Header Description
User-Agent User-Agent The classic browser identification string
Sec-CH-UA Sec-CH-UA Comma-separated list of browser brands and major versions
Sec-CH-UA-Mobile Sec-CH-UA-Mobile ?1 if mobile device, ?0 otherwise
Sec-CH-UA-Platform Sec-CH-UA-Platform Operating system name (e.g. "Windows", "macOS")
Sec-CH-UA-Platform-Version Sec-CH-UA-Platform-Version OS version string
Sec-CH-UA-Arch Sec-CH-UA-Arch CPU architecture (e.g. "x86", "arm")
Sec-CH-UA-Bitness Sec-CH-UA-Bitness CPU bitness ("32" or "64")
Sec-CH-UA-Model Sec-CH-UA-Model Device model name (primarily for mobile)
Sec-CH-UA-Full-Version-List Sec-CH-UA-Full-Version-List Full version strings for all brands
Sec-CH-UA-Form-Factors Sec-CH-UA-Form-Factors Form factor hints (e.g. "Desktop", "Phone", "Tablet")

Tips

  • If your browser does not support the Client Hints API, the auto-detect button will fall back to reading only the User-Agent string and will show a warning.
  • When using the Raw Headers tab, paste headers exactly as they appear in your browser's DevTools Network panel — one header per line in Name: Value format.
  • The Sec-CH-UA header intentionally includes fake brand entries (like "Not-A.Brand") to prevent fingerprinting; the tool filters these and shows the real browser name.