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NeatUtility

User-Agent Parser & Client Hints Inspector

Web & API100% Client-Side
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About this tool, examples & FAQ

Analyze User-Agent strings locally with zero server requests. Decode browser brand, version, rendering engine, operating system, and hardware architecture, detect crawlers and bots, and generate equivalent modern Sec-CH-UA Client Hints headers.

Key facts

Verified capabilities and limits of this utility
Client Hints StandardW3C User-Agent Client Hints (Sec-CH-UA, RFC 8942)
Device TypesDesktop, Mobile, Tablet, and Automated Bot / Crawler
Maximum Input25 KB
Execution Deadline2 s

How to use

  1. Paste any User-Agent string from web server logs, browser DevTools, or analytics reports.
  2. Select your target view: User-Agent Analysis, Structured JSON, or Client Hints Headers.
  3. Optionally toggle search bot detection or Client Hints generation in the options drawer.
  4. Click Run (or press Ctrl/Cmd + Enter) to immediately parse device and browser attributes.
  5. Copy the diagnostic breakdown or export the structured JSON schema into your application.

Example

Parse modern desktop Chrome User-Agent string on Windows 64-bit

Input

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Example output

=== User-Agent Breakdown ===
Browser:         Chrome 128.0.0.0
Rendering Engine:Blink 537.36
Operating System:Windows 10 / 11
Device Category: Desktop
Architecture:    x86_64
Classification:  Standard User Browser

Equivalent Client Hints (Sec-CH-UA):
  Sec-CH-UA:          "Chrome";v="128"
  Sec-CH-UA-Mobile:   ?0
  Sec-CH-UA-Platform: "Windows"

Edge cases

User-Agent Reduction and Freezing

Modern browsers (Chrome, Edge, Firefox) have frozen parts of the User-Agent string (e.g. freezing OS versions at Windows NT 10.0 or Mac OS X 10_15_7) to combat cross-site fingerprinting. Accurate granular versions require User-Agent Client Hints.

Compatibility Strings and Previews

Historic compatibility prefixes like `Mozilla/5.0` and `like Gecko` are present in nearly all modern browsers for backwards compatibility with legacy servers.

Headless and Bot Identification

Automated scrapers and test suites (Puppeteer, Playwright, Selenium) often append `HeadlessChrome` or custom bot tokens unless explicitly configured with standard user-agent strings.

How it works

  1. Evaluates the User-Agent string against pattern matching rules for browser families and engines.
  2. Extracts major and patch versions for rendering engines (Blink, Gecko, WebKit, Trident).
  3. Identifies host operating systems and hardware architecture bits (x86_64, ARM64).
  4. Maps parsed attributes to the modern W3C User-Agent Client Hints standard (Sec-CH-UA).

Related workflows

Frequently asked questions

What are User-Agent Client Hints (UA-CH)?

User-Agent Client Hints is a privacy-preserving modern web standard that replaces bloated, fingerprintable User-Agent strings with structured HTTP headers (Sec-CH-UA, Sec-CH-UA-Mobile, Sec-CH-UA-Platform).

Why does Chrome's User-Agent contain 'Safari'?

Historically, WebKit browsers like Safari added compatibility tokens, and when Chrome launched on WebKit (prior to Blink), it included 'Safari' to prevent early web servers from denying access.

Is the parsed User-Agent string sent to any remote server?

No. All parsing and header generation execute 100% locally in your web browser via client Web Workers. Zero telemetry or server transmission occurs.

References