User Agent Detector — See Your Browser, OS & Device Info
Detect your User Agent string, browser, OS, device type, and capabilities. Test bot detection, debug device-specific bugs. Free.
About User Agent Parser
A user agent detector reveals the User-Agent (UA) string your browser sends with every HTTP request — the identification of browser name, version, rendering engine, operating system, and device type. Used by web servers for analytics, conditional content (mobile vs desktop layouts), bot detection, and debugging device-specific bugs. The ZTools User Agent Detector parses the current request UA, displays it in a structured way (browser / version / OS / engine / device / type), and shows the modern Client Hints values (browsers progressively replacing the UA string). Useful for QA, debugging, and bot/automation testing.
Use cases
- Mobile / desktop testing. Verify your "is this a mobile device?" detection works correctly across iPhone, Android, iPad, desktop, etc.
- Bug reporting. When filing a browser-specific bug, attach UA + parsed details to the report — saves the engineer triage time.
- Bot detection debugging. Test how your site treats different UAs — bot-like UAs should not get challenged. Whitelist known good bots (Googlebot, Bingbot).
- Compatibility checks. Old browser UAs help confirm whether your site renders correctly on legacy users (or whether to drop support).
How it works
- View current UA. Displays your browser's User-Agent header verbatim.
- Parsed breakdown. Browser name + version, OS name + version, rendering engine (Blink / Gecko / WebKit), device type (desktop / mobile / tablet / TV / wearable).
- Client Hints. Modern browsers send `Sec-CH-UA-*` headers; tool displays available values.
- Capabilities check. Touch, WebGL, WebRTC, Service Workers, Web Push — quick capability summary.
- Copy raw UA. For pasting into bug reports.
Examples
Input: iPhone 16 Pro Safari
Output: `Mozilla/5.0 (iPhone; CPU iPhone OS 18_3...)` parsed as: Safari 18 / iOS 18 / Mobile / WebKit.
Input: Chrome desktop
Output: `Mozilla/5.0 (Windows NT 10.0...)` parsed as: Chrome 138 / Windows 10 / Desktop / Blink.
Input: Googlebot UA
Output: `Mozilla/5.0 (compatible; Googlebot/2.1; +https://...)` flagged as Bot / Crawler.
Frequently asked questions
Why does the UA say "Mozilla/5.0" even for non-Mozilla browsers?
Historical: in 1990s, sites required "Mozilla" to ship modern HTML. Browsers spoofed it for compatibility, and the convention stuck. Every modern browser starts UA with "Mozilla/5.0" for legacy reasons.
What's "Client Hints"?
Modern (post-2020) replacement for the UA string. Servers request specific hints (browser brand, model, full version) via HTTP headers, reducing fingerprinting surface area while preserving useful signals.
Can I spoof my UA?
Yes — browsers expose dev-tool UA override (Chrome DevTools → ⋮ → More tools → Network conditions). Useful for testing mobile-vs-desktop responsive views.
Why does my UA have "iPad" but the site treats me as desktop?
iPadOS 13+ defaults to desktop UA on iPad to encourage desktop-class web experience. Some sites are catching up; iPad-specific detection often requires Touch capability + screen size, not UA.
Is my UA unique enough to fingerprint me?
Combined with screen size, fonts, timezone, etc., yes — UA contributes meaningfully to browser fingerprinting. Modern browsers (Brave, Firefox with strict mode) randomise/reduce UA precision to mitigate.
Should I do UA detection in my code?
Prefer feature detection (`if (navigator.serviceWorker)`) over UA detection — UAs lie, features tell the truth. Reserve UA for analytics and bot detection.
Pro tips
- Always include UA + browser version in bug reports — saves engineering triage time.
- For detection logic, prefer feature detection over UA parsing — more reliable.
- Test UA spoofing in DevTools when QAing mobile responsiveness from desktop.
- Watch out for iPad-as-desktop UA gotcha — affects ~5% of users.
- Modern Client Hints will replace UA over coming years — design for both.
Reviewed by Ahsan Mahmood · Last updated 2026-05-06 · Part of ZTools.
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