Every browser request carries a user-agent string, and most of them read like alphabet soup: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 .... This user-agent parser translates that soup into plain answers — which browser, which version, which engine, which operating system, which kind of device.
Paste a UA from your server logs, an analytics export or a bug report — or press one button to parse the user agent of the browser you are using right now. Everything is analysed locally; the string you paste is never sent anywhere.
Why every UA claims to be Mozilla
The string starts with Mozilla/5.0 because of a 1990s arms race: browsers began pretending to be other browsers to get the “good” version of websites, and the costume became permanent. Chrome’s UA also contains “Safari” and “AppleWebKit”; Edge’s contains “Chrome” and “Safari” and its own “Edg”. That is why parsing order matters: this tool checks for Edge, Opera, Samsung Internet and other Chrome-based browsers before concluding “Chrome”, and checks for Chrome before concluding “Safari” — exactly the trap order that naive parsers get wrong.
What can actually be known from a UA
Browser and version are the reliable part. Engine follows from the browser: Blink for Chrome/Edge/Opera, Gecko for Firefox, WebKit for Safari. Operating system is usually named outright — with one famous catch: “Windows NT 10.0” is reported by both Windows 10 and Windows 11, so no parser can honestly separate them from the UA alone; this tool says “10/11” and means it. Device is partially honest: Android strings often include the handset model (a gift — it is shown in the model row), iPhones and iPads never do, and a “Mobile” token separates phones from tablets and desktops.
A worked example
Press “Use my browser” and read your own string through the parser’s eyes. On an Android phone you will typically see the model extracted from the parenthesised segment (“SM-G991B” is a Galaxy S21); on an iPhone the model row honestly says iPhone, because Apple’s strings deliberately name nothing more specific. Comparing the raw string with the parsed table is the quickest way to build intuition for what your analytics tool is doing behind the scenes.
Honest limits — read this before trusting any UA
User agents are claims, not facts. Any client can send any string: bots routinely impersonate Chrome, privacy browsers strip or freeze details, and modern Chrome increasingly sends a reduced UA with the detailed model moved behind Client Hints headers. That shift is worth understanding: the classic string in this tool is gradually becoming the summary, while the fine print moves to Sec-CH-UA request headers that a server must explicitly ask for. When a log line seems to know less about a visitor than it did in 2019, that is usually why — the data did not vanish, it moved house.
So use UA parsing for debugging, log analysis and rough analytics — “which browsers hit this error?” — and never as a security boundary or proof of who visited.
Frequently asked questions
Why does my Chrome on iPhone show as Safari engine?
Because on iOS every browser is required to use Apple’s WebKit engine under the hood — Chrome for iOS (CriOS) is genuinely a WebKit browser wearing a Chrome interface, and the parser’s engine row tells you so.
The version shows only the major releases correctly?
The parser reports the version written in the string. Some browsers freeze parts of it for privacy (you may see minor components zeroed, like 120.0.0.0) — that is the browser’s choice, faithfully reflected.
Can this identify a specific phone from any UA?
Only when the string volunteers it — Android often does; iOS never does. Anything beyond that in other tools is database guessing, not parsing.
Is the UA I paste uploaded?
No. The analysis is string matching in your browser tab.
Related tools
Versión en español: Analizador de User Agent — Lee Cualquier Cadena de User Agent Online. You may also like: DNS Record Checker — Look Up A, AAAA, MX, TXT, CNAME and NS Records · IP Subnet Calculator — CIDR, Netmask, Broadcast and Host Range.
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