User-Agent Parser & Analyzer
Paste any User-Agent string to identify the browser, operating system, device, and rendering engine instantly.
About This Tool
The User-Agent Parser & Analyzer is a free browser-based tool that decodes User-Agent (UA) strings into structured, human-readable components. Every HTTP request includes a User-Agent header that identifies the client software making the request — typically a web browser, but also bots, crawlers, mobile apps, and command-line tools like curl.
Understanding User-Agent strings is essential for web developers, QA engineers, and DevOps teams. UA strings control content negotiation, responsive design decisions, analytics segmentation, and bot management. However, the format is notoriously messy: modern browsers include legacy tokens for compatibility (the famous "Mozilla/5.0" prefix), making manual parsing unreliable.
This tool extracts the following components from any UA string:
- Browser name and version — Chrome, Firefox, Safari, Edge, Opera, Samsung Internet, UC Browser, Brave, Vivaldi, and more
- Operating system and version — Windows 10/11, macOS, Linux, Android, iOS, iPadOS, Chrome OS
- Device type — Desktop, Mobile, or Tablet, along with brand and model when available
- Rendering engine — WebKit, Gecko, Trident, Blink (reported as WebKit by Chrome)
- Bot / crawler detection — Googlebot, Bingbot, DuckDuckBot, social media crawlers, AI agents, and generic bot patterns
All parsing runs entirely in your browser using JavaScript regular expressions. No data is sent to any server — your UA strings remain private. The built-in library of 25+ common User-Agent strings lets you quickly test against real-world browser, mobile, and bot UAs without leaving the page.
If you work with HTTP headers, you may also find the HTTP Header Analyzer useful. For keyboard event debugging, check out the Event KeyCodes Tester. And for inspecting HTTP response codes during testing, see the HTTP Status Codes reference.
How to Use
- When the page loads, your current browser's User-Agent is automatically detected and parsed.
- To analyze a different UA string, paste it into the User-Agent String text area and click Parse (or press Ctrl+Enter).
- Click Detect My Browser to re-detect your current browser's UA string at any time.
- Open the UA Library panel to browse 25+ common User-Agent strings for Chrome, Firefox, Safari, mobile browsers, and bots — click any entry to parse it instantly.
- Review the parsed results in the summary card (browser name, OS, device icon) and the detail table (all extracted components).
- Click the Copy button (or press Ctrl+Shift+C) to copy the structured results to your clipboard.
- Click Clear to reset the input and results.
Popular User-Agent Parsing Examples
FAQ
Is my data safe when using this tool?
Yes. All User-Agent parsing is performed entirely in your browser using JavaScript regular expressions. No data is transmitted to any server, logged, or stored. Your UA strings remain completely private.
What is a User-Agent string?
A User-Agent string is an HTTP header sent by web browsers and other HTTP clients to identify themselves to the server. It typically includes the browser name and version, operating system, rendering engine, and device information. Servers use this information for content negotiation, analytics, and compatibility handling.
Why do most User-Agent strings start with Mozilla/5.0?
This is a historical artifact from the early browser wars. When Netscape Navigator (code-named Mozilla) was the dominant browser, many servers served richer content only to Mozilla-compatible browsers. Other browsers started including 'Mozilla/5.0' in their UA strings to avoid being served degraded content. The practice persists today across virtually all modern browsers.
Can this tool detect bots and crawlers?
Yes. The parser checks for 25+ known bot patterns including Googlebot, Bingbot, DuckDuckBot, social media crawlers (Facebook, Twitter, LinkedIn), AI agents (ChatGPT, GPTBot), SEO tools (Ahrefs, Semrush), and command-line clients (curl, wget, Python Requests). Unknown bots are caught by generic patterns matching keywords like 'bot', 'crawler', and 'spider'.
How accurate is User-Agent parsing?
UA parsing is inherently heuristic because there is no strict standard for the format. This tool accurately identifies all major browsers, operating systems, and bots using carefully ordered regex patterns. However, some UA strings are intentionally spoofed, and new browsers or bots may not be recognized until their patterns are added.
Does this tool handle mobile User-Agent strings?
Yes. The parser detects mobile browsers including Chrome for Android, Safari on iPhone and iPad, Samsung Internet, Firefox for Android, and UC Browser. It also identifies the device type (Mobile, Tablet, or Desktop) and extracts device brand and model when available in the UA string.
What keyboard shortcuts are available?
Press Ctrl+Enter to parse the current UA string. Press Ctrl+Shift+C to copy the parsed results to your clipboard.
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