User Agent Parser: decode browser, OS & device
Free in-browser user agent parser. Decodes browser, version, engine, OS and device from any UA string. Your own UA is pre-filled so you can answer "what's my user agent?" in one glance. Powered by ua-parser-js.
Raw JSON
When to parse a user agent string
Analytics & QA
Identify the browser, version and OS distribution behind a bug report or analytics anomaly.
Debug a server log
Paste a UA from a server log line to instantly see which browser, device and engine hit your endpoint.
Device targeting
Confirm whether a UA represents mobile, tablet, desktop or bot — and dig into the Client Hints for the model and platform version.
Bot / scraper detection
Spot Googlebot, Bingbot, GPTBot, ClaudeBot and headless tools from their UA signatures.
Feature support audit
The capabilities matrix tests touch, WebGL, WebGPU, codecs, Service Worker and 20+ other features live in your browser.
Fingerprint check
See the FingerprintJS visitor ID you broadcast to every site — and how much entropy your browser leaks via canvas, audio and fonts.
How to use the user agent parser
See your own UA
Your current user agent is pre-filled. Click My UA any time to restore it after experimenting.
Paste another UA
From a server log, a bug report, a curl command or one of the preset chips (Chrome, Safari, Firefox, Edge, Googlebot). The result updates as you type.
Compare two UAs
Click Compare two UAs to open the diff card and paste a second string — differences are colour-highlighted.
Read the extra cards
UA Client Hints (Chromium only), the live browser-capabilities matrix, Network Information API, and a FingerprintJS open-source visitor ID.
About user agent strings, UA-CH and browser fingerprinting
A user agent (UA) string is a short text identifier every browser and HTTP client sends in the User-Agent request header. It typically lists the product, version, operating system, device model and rendering engine. Servers use it for analytics, content negotiation and feature detection. This online user agent parser decodes any UA into browser / engine / OS / device / CPU fields using the open-source ua-parser-js library — entirely in your browser, no upload, no signup.
Anatomy of a modern UA string
Take Chrome on Windows: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36. The Mozilla/5.0 is historical noise dating back to Netscape compatibility wars. Windows NT 10.0; Win64; x64 is the OS and architecture. AppleWebKit/537.36 is the engine (Blink is based on WebKit). Chrome/120.0.0.0 is the browser and version. Safari/537.36 is more compatibility noise. Almost every modern browser pretends to be every other browser — which is why parsing libraries exist at all.
User-Agent Client Hints (UA-CH)
Google is gradually freezing the UA string and replacing it with User-Agent Client Hints — a set of structured headers (Sec-CH-UA, Sec-CH-UA-Platform, Sec-CH-UA-Mobile) plus the navigator.userAgentData.getHighEntropyValues() JS API. Hints expose more than the legacy UA (real device model, full platform version) but only on request, so privacy-conscious browsers can opt out. The UA-CH card on this page calls the API live and shows what your browser would reveal.
The capabilities matrix
UA strings tell you what the browser claims to be. The capabilities matrix tells you what the browser can actually do: touch points, WebGL / WebGL2 / WebGPU, Service Worker, WebAssembly, SharedArrayBuffer, Web Push, Notifications, Geolocation, Bluetooth, USB, NFC, VR, Battery, Storage Estimate, async Clipboard, Web Share, Wake Lock, IndexedDB, and codec support for VP9 / AV1 / HEVC / Opus. Each is tested live — green means yes, red means no.
FingerprintJS browser fingerprint
The FingerprintJS open-source library (MIT licence) generates a stable visitor ID from signals every browser leaks: canvas rendering quirks, audio context fingerprint, installed fonts, screen resolution, timezone, CPU concurrency, deviceMemory, vendor and a dozen others. The same ID typically persists across browsing sessions, incognito mode, and even some VPN switches — that's the same technique advertisers and fraud-detection vendors use to identify you. Seeing your own ID is sobering.
Network Information API
The navigator.connection object (Chromium-only at full quality) exposes the effective connection type (4g, 3g, slow-2g), measured downlink in Mbps, round-trip estimate, and the Data Saver flag. Great for client-side adaptive loading — serve smaller images or lower-bitrate video to slow connections.
Diff mode
The compare card lets you paste two UA strings side by side and instantly see which fields changed — perfect for QA bug reports that come in from different users, or for confirming the impact of a browser update.
User Agent Parser — frequently asked questions
A user agent (UA) is a string browsers and apps send with every HTTP request to identify themselves. It typically contains the product, version, operating system, device model and rendering engine. Servers use it for analytics, content negotiation and feature detection.
It uses ua-parser-js, a well-maintained open source library that pattern-matches UA strings against known browser, OS, device and engine signatures. Everything runs in your browser.
No. Parsing happens entirely on your device. You can use the tool offline once the page is loaded.
Yes. Paste any UA string into the input field. The result updates as you type.