User Agent Parser & Device Detector
Parse any browser user agent string into browser, OS, device, engine, and bot details. Deterministic local parsing with JSON output, token breakdown, and shareable links — no API required.
How to parse a user agent string
Paste any HTTP User-Agent header value into the tool above. Parsing runs instantly in your browser using an ordered rule set — no upload and no external API. Use sample presets for common desktop browsers, mobile devices, and crawlers, or share a link with encoded input for reproducible debugging.
What browser, OS, and device details can be inferred
Typical user agents expose browser name and version, rendering engine family, operating system, device class (desktop, mobile, tablet), vendor/model hints on mobile UAs, and CPU architecture tokens such as x64 or arm64. Not every field appears in every string — privacy-focused browsers and UA reduction policies intentionally omit details.
How bot and crawler detection works
The parser checks for well-known crawler signatures first — including Googlebot, Bingbot, DuckDuckBot, YandexBot, Baiduspider, Slackbot, Twitterbot, and facebookexternalhit — before evaluating browser tokens. This ordering avoids false positives when bots embed Chrome or Safari compatibility strings.
Limits of user agent parsing and spoofing
User agent strings are self-reported and easily spoofed. Client hints, IP reputation, and behavioral signals are often more reliable for production bot filtering. Use this tool for debugging, analytics QA, and support triage — not as the sole source of truth for security decisions.
Frequently Asked Questions
What is a user agent string?
A user agent (UA) string is a text identifier sent by browsers, apps, and crawlers with HTTP requests. It typically describes the client software, operating system, and sometimes device model. Developers and analysts inspect UAs during debugging, analytics validation, and support workflows.
How does this user agent parser work?
The parser applies a deterministic, ordered rule set entirely in your browser. It looks for bot signatures first, then browser families (Edge before Chrome, Samsung Internet, Firefox, Safari, and others), operating system tokens, device hints, and CPU architecture markers. Results include a summary, JSON output, and a token breakdown explaining matched segments.
Can user agent parsing detect bots reliably?
This tool identifies common crawlers such as Googlebot, Bingbot, Slackbot, and Twitterbot when their signatures appear in the UA string. However, bots can spoof legitimate browser UAs, and some legitimate traffic uses reduced UA strings. Treat bot detection here as a quick heuristic, not a production-grade filter on its own.
Why do my parsed browser or OS details look wrong?
Browsers increasingly reduce or freeze user agent data for privacy. Extensions, corporate proxies, and compatibility modes can also alter the string. Spoofing is trivial — compare results with client hints, IP data, or session context when accuracy matters.
Is my user agent sent to a server?
No. After the page loads, all parsing happens locally in your browser. Nothing is uploaded unless you explicitly share a link containing encoded sample input in the URL.