User Agent Parser

A user agent string packs several layers into one line. It almost always opens with "Mozilla/5.0", a legacy token nearly every browser still sends for historical compatibility, so it tells you nothing about the real browser. Inside the parentheses sits the platform block: the operating system, its version, and the CPU architecture, such as "Windows NT 10.0; Win64; x64" or "iPhone; CPU iPhone OS 17_1". After that come the rendering engine and its version, like "AppleWebKit/537.36 (KHTML, like Gecko)", followed by the actual browser token, such as "Chrome/120.0" or "Safari/605.1". The parser separates each of these into clean, labelled fields so you do not have to read the raw string. Paste any string above and it splits browser, OS, device, engine, and CPU for you instantly.

It reads device cues from the string rather than guessing from screen size. A phone is flagged when the string contains tokens like "Mobile", "iPhone", "iPod", or "Android" alongside "Mobile". A tablet is detected from "iPad", "Tablet", or — importantly — "Android" without the "Mobile" keyword, because Android tablets drop that word while phones keep it. That single "Mobile" token is the main signal Google and other servers use to separate the two, which is why an Android tablet and an Android phone can otherwise look almost identical. Anything that matches neither pattern is treated as desktop, and recognised crawlers are tagged as bots. Where the model is exposed, such as a Pixel or an SM-series Samsung, the parser surfaces the vendor and model too. Paste a string above to see the device type it resolves to.

Yes. A user agent string is just a request header, and it can be edited or spoofed freely, so it is evidence rather than proof. Anyone can set their string to claim they are Googlebot, an iPhone, or any browser they like, which is why traffic that looks like a search crawler in your logs may be a scraper wearing a disguise. To confirm a self-declared bot, do not trust the string alone: run a reverse DNS lookup on the visitor's IP, check that it resolves to the crawler's official domain, then do a forward lookup back to the same IP. Google, Bing, and others publish this verification method. The parser flags roughly two dozen known crawlers by name and reminds you to verify them, but the lookup itself is the real test. Paste a suspicious string above to see what it claims to be.

Modern browsers are deliberately freezing and trimming their user agent strings to reduce fingerprinting and the privacy risk that a highly specific string creates. Chrome and other Chromium browsers now often report a reduced string with a frozen or rounded version — frequently showing only the major version with minor digits zeroed — instead of the exact build number. The detailed values that used to live in the string have moved to User-Agent Client Hints, a separate set of headers a server must explicitly request. So if the parser shows a version that looks rounded or behind your installed build, the string itself is the limitation, not the tool. The Fingerprint tab reads live values straight from your browser's navigator and screen objects to show what is still exposed beyond the string. Click "My Browser" above to load your real string and compare what it does and does not reveal.

They answer three separate questions, and the parser reports each on its own line. The browser is the application the person is using — Chrome, Firefox, Safari, Edge, Brave, or Samsung Internet — and it is what most people mean by "what browser is this". The rendering engine is the underlying software that lays out and paints the page: Blink powers Chrome, Edge, Opera, and Brave; WebKit powers Safari; Gecko powers Firefox; Trident powered old Internet Explorer. This is why several different-looking browsers can behave identically — they share an engine. The operating system is the platform underneath both, such as Windows 11, macOS, iOS, or Android, with its own version. Separating these helps you pin down whether a bug is browser-specific or engine-wide. Paste a string above to see all three fields broken out cleanly.