User-Agent Parser

A User-Agent parser decodes the User-Agent string a browser sends in its request headers into readable fields: browser name and version, operating system, device type, and rendering engine. The UA string is one of the messiest pieces of the web. For historical compatibility reasons almost every browser still claims to be Mozilla, and Chromium-based browsers like Chrome, Edge, Brave, Opera, and Vivaldi all carry similar tokens, so telling them apart takes pattern matching rather than a simple lookup. This tool applies those patterns to split a UA into clean fields, distinguishes the major Chromium browsers from one another, maps OS tokens such as Windows NT, Mac OS X, iPhone OS, and Android to recognizable names and versions, and flags strings that look like bots or crawlers (Googlebot, bingbot, HeadlessChrome, and similar). It is important to understand what UA parsing can and cannot do, and this is the key gotcha: User-Agent parsing is heuristic, not authoritative. The string is sent by the client and is trivially editable, so it can be spoofed, and parsers infer the browser from known patterns rather than reading a verified fact. This tool matches the common real-world strings and is correct for the large majority of genuine traffic, but exotic, very old, or deliberately faked UAs may be misclassified, and a sophisticated bot can present a UA identical to a real Chrome on Windows. Two more caveats worth knowing: modern browsers freeze or reduce UA detail (Chrome reports a frozen version and pushes precise data to the separate Client Hints headers), and iPadOS often reports a desktop Mac UA by default, so an iPad can look like a Mac. Treat the output as a strong hint for analytics, debugging, and log auditing, not as proof of identity. The string you paste is parsed entirely in your browser and is never uploaded.