DevKit

User Agent Parser

Paste a User-Agent header to identify the browser, engine, OS, device type and crawlers. Your own browser's UA is loaded to start, and samples are one click away.

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About the User Agent Parser

User-Agent strings are historical layers of compatibility claims: nearly every browser still starts with Mozilla/5.0, Chrome includes Safari/537.36, and Edge adds Edg/ to a Chrome string. The parser therefore checks the most specific tokens first (Edge, Opera, Samsung Internet, then Chrome, then Safari) and knows that every iOS browser uses WebKit, whatever its name.

Modern browsers deliberately hide detail. Chrome's reduced UA reports only the major version, freezes Android devices as Android 10; K, and Windows 11 still says Windows NT 10.0. macOS is frozen at 10.15.7, and iPads send a Mac UA by default. For exact values, request User-Agent Client Hints such as Sec-CH-UA-Platform-Version.

Crawlers (Googlebot, Bingbot, GPTBot, ClaudeBot, social previewers) and HTTP clients such as curl or python-requests are detected by their tokens. The UA header is trivially spoofed, so verify real crawlers by reverse DNS on the requesting IP before trusting them. Parsing runs locally with regular expressions; nothing is sent anywhere.

How to use it

  1. Your browser's User-Agent is filled in automatically.
  2. Paste another UA from your server logs, or click a sample.
  3. Read browser, engine, OS and device type in the result.
  4. Copy the JSON to use in tests or reports.

Frequently asked questions

What is my user agent?
It is loaded in the input box when the page opens. Click My browser to restore it after trying other strings.
Why does Chrome's user agent mention Safari and Mozilla?
For compatibility: old sites served features only to browsers that claimed to be Mozilla or Safari, so every new browser copied those tokens.
How can I tell Windows 10 from Windows 11?
Not from the UA string, which is Windows NT 10.0 for both. Use navigator.userAgentData.getHighEntropyValues(['platformVersion']); versions 13 and above are Windows 11.
Should I use UA sniffing to detect features?
Prefer feature detection (CSS @supports, 'x' in window). Use the UA for analytics, bot filtering or working around a specific known browser bug.

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