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User Agent Parser

Parse a User-Agent string.

beats whatismybrowser.com edge: Bot detection + your UA inline
UA string
parsed
Guide

About User Agent Parser

Paste any User-Agent string and the parser decodes browser, version, OS, platform, and bot status (Googlebot, Bingbot, GPTBot, etc.). Also shows your current browser's UA. Useful for analytics pipelines, debugging client-specific bugs, and triaging support tickets where the UA tells you the affected platform.

What’s in a UA string

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15
  (KHTML, like Gecko) Version/17.0 Safari/605.1.15

Decodes to:

  • Browser: Safari 17
  • Engine: WebKit 605.1.15
  • OS: macOS 10.15.7
  • Device: Desktop

The “Mozilla/5.0” prefix is historical — every browser includes it for compatibility with 2000s server-side sniffing.

Common workflows

Triage a bug report. Customer’s UA in support ticket → parse → see browser/OS/version. Reproduce on the same combo.

Audit analytics. Drop a list of UAs through the tool, classify by browser family. Spot patterns in incident reports.

Bot filtering. Filter UA list against the bot catalog. Real users vs known crawlers.

Build the right warning banner. Detect IE 11 (still hangs around in enterprise) — surface deprecation message.

Why UA detection is mostly wrong

  • UAs lie (every browser pretends to be Mozilla)
  • UAs change (Chrome version strings update weekly)
  • UAs are spoofable
  • Feature detection is more reliable for capabilities
  • User-Agent Client Hints replaces this entirely

For legitimate UA needs (analytics aggregation, server-side rendering choices), this tool helps. For runtime feature decisions in code, use if ('feature' in window).

Frequently asked questions

Why are UA strings such a mess?
Historical accident. Every browser pretends to be every other browser to dodge old user-agent sniffing logic. Chrome's UA contains "Mozilla", "AppleWebKit", "Safari" — none of which it actually is.
Is UA detection reliable?
For coarse browser/OS classification, yes. For feature detection, no — use feature detection ('fetch' in window) instead of UA sniffing.
What is User-Agent Client Hints?
Modern alternative — structured headers like Sec-CH-UA, Sec-CH-UA-Mobile, Sec-CH-UA-Platform. Replaces UA sniffing with explicit, queryable client info. Chrome 90+ sends them by default.
How does bot detection work?
We match against a curated bot UA list. Most legit bots identify themselves clearly (Googlebot/2.1, GPTBot/1.0). Sneaky bots disguise as normal browsers — UA detection alone won't catch them.
Mobile vs desktop?
The UA usually contains "Mobile" for phones / tablets, but this is unreliable. Use Sec-CH-UA-Mobile or viewport size for confident detection.
Is UA parsed locally?
Yes. Pattern matching runs in the browser; no API call.

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Last updated: 2025-01-15