User Agent Parser

Paste a User-Agent string and this breaks it into the four things you usually care about: browser and version, operating system, device type (desktop, mobile, tablet, or bot), and rendering engine. It loads your own browser's User-Agent automatically, so you can see how you appear to a server right away, or paste one from a log to identify a visitor.

User-Agent strings are notoriously messy — a Chrome UA still contains the words "Mozilla", "AppleWebKit", "KHTML", "like Gecko", and "Safari" for historical compatibility reasons. That's why reading them by eye is error-prone. This pulls out the parts that actually matter and labels them, so you don't have to remember which token means what.

It's most useful for quick debugging: checking what a request in your server logs came from, confirming your own browser identity, or sanity-checking device detection. For anything you rely on in production, treat the result as a best guess — see the notes below on why User-Agent parsing is fundamentally unreliable.

Parsing is done with a set of ordered regular expressions in your browser. Browser detection checks in a deliberate order — Edge (Edg/), Opera (OPR/), then Firefox, Chrome, Safari, and Internet Explorer — because their tokens overlap. Edge and Opera both include "Chrome" in their strings, so they must be matched first or they'd be misidentified as Chrome. Version numbers are captured from the matching token.

OS detection maps the familiar markers: Windows NT 10 (which covers both Windows 10 and 11 — Microsoft never bumped the NT version), Android and iOS with their version numbers, macOS (with underscores converted to dots), and Linux. Device type is inferred from Mobile/iPhone/iPad/Tablet markers, and a bot check looks for bot, crawl, spider, slurp, and bingpreview. Engine is derived from the browser family: Blink for Chrome/Edge/Opera, WebKit for Safari, Gecko for Firefox, Trident for old IE.

Everything runs locally — the UA you paste is never sent anywhere.

Dedicated libraries like UAParser.js and server-side services maintain large, constantly updated device and browser databases, so they recognize far more edge cases (specific phone models, obscure browsers, bot fingerprints) than this tool's compact regex set. If you need production-grade detection or exhaustive device data, use one of those.

This tool is for the quick lookup: identifying the common browsers, OSes, and device classes without leaving the page or writing code. It gets the mainstream cases right and shows you the reasoning. For occasional debugging that's usually all you need; for analytics you depend on, reach for a maintained library — and lean on client hints where you can.