A user-agent parser decodes the opaque UA string that browsers send with every HTTP request, identifying the browser name and version, rendering engine, operating system, device type, and CPU architecture. Paste any user-agent string below — or click "Use my browser" to analyze your own.
User Agent String
Raw User-Agent String
Parsed Result (JSON)
Recent (last 5)
How to Use the User Agent Parser
User-agent strings are HTTP headers sent by browsers with every web request. They tell web servers what browser and OS is being used so the server can tailor responses. While powerful, UA strings are notoriously cryptic — a typical Chrome UA string on Windows contains references to Mozilla, AppleWebKit, Safari, and Chrome all at once. This free parser decodes them instantly.
Step 1: Get a User-Agent String
Click "Use my browser" to auto-fill your current browser's UA string. Alternatively, paste any UA string you've found in HTTP logs, analytics data, API requests, or from a remote device. You can also test with known UA strings from different browsers and devices to understand how they differ.
Step 2: Read the Component Cards
After parsing, you'll see component cards for: Browser (name, major version, full version), Engine (Blink, Gecko, WebKit, etc. with version), OS (operating system name and version), Device (model, type, and vendor — desktop, mobile, tablet, bot), and CPU (architecture — amd64, arm, arm64, ia32, etc.).
Step 3: Copy Parsed JSON
The full parsed result is available as JSON for easy integration into your code. Copy the raw UA string or the parsed JSON object with the copy buttons. The history panel shows your last 5 parsed UAs — click any to re-parse it.
Common Use Cases for UA Parsing
Web developers use UA parsing for: serving different CSS to old browsers, detecting mobile devices for redirects, filtering bot traffic in access logs, debugging user-reported issues ("it breaks on my phone"), building browser compatibility matrices, and segmenting analytics by browser or OS version. With increasing user-agent freezing in Chrome (reducing entropy for privacy), UA Client Hints are becoming the modern alternative for server-side detection.
FAQ
Is this user agent parser free?
Yes, completely free. Paste any user-agent string and parse it instantly — no signup, no account required.
Is my data private?
All parsing happens in your browser using the ua-parser-js library. Your user-agent strings never leave your device.
What is a user-agent string?
A user-agent (UA) string is a text identifier that browsers send in HTTP request headers to identify themselves to web servers. It contains the browser name and version, rendering engine, operating system, and device type. Web analytics tools use UA strings to report visitor browser/OS statistics.
Why do user-agent strings look so complex?
UA strings evolved for historical compatibility reasons. When Netscape dominated, new browsers identified as 'Mozilla-compatible' to receive the same content. This created a pattern of UA strings containing many browser names for backward compatibility, making them complex to parse correctly.
What can I do with parsed user-agent data?
Use UA parsing for: server-side feature detection, blocking bots and scrapers, analytics breakdowns by browser/OS, responsive design debugging, A/B test segmentation, and serving browser-specific content or fallbacks.
Does this detect bots and crawlers?
The tool identifies known bots (Googlebot, Bingbot, etc.) through the ua-parser-js library. The device type field will show 'bot' for recognized crawlers. However, sophisticated bots that disguise as real browsers may not be detected.
What is the 'Use my browser' button?
Clicking 'Use my browser' fills the input with your current browser's navigator.userAgent string, letting you see exactly what data your browser sends to websites you visit.