User Agent Parser
Detect browser, OS, and device type from a user agent string.
About User Agent Parser
A user agent string is a short piece of text sent by your browser with every HTTP request. It tells servers which browser, operating system, and device you are using. This tool parses any user agent string and extracts the browser name and version, rendering engine, operating system, device type, and CPU architecture. Your current browser's user agent is loaded automatically when you open the tool.
FAQ
- What is a user agent string?
- A user agent string is sent by your browser with every HTTP request to identify itself — including the browser name, version, and operating system.
- Where can I find my user agent?
- It's auto-filled when you open this tool. You can also find it in browser dev tools under the Network tab.
- Can I test any user agent?
- Yes — paste any user agent string into the input field and click Parse.
- Why do some fields show as unknown?
- Not all user agent strings include complete information, especially for bots and non-standard clients.
ABOUT THIS TOOL
Paste a user agent string - the identifying text every browser sends with its HTTP requests - and break it down into browser name and version, operating system, rendering engine, and device type such as desktop, mobile, tablet, or bot. User agent strings look consistent but are notoriously messy under the hood: for historical compatibility reasons, nearly every browser's UA string still contains the word Mozilla, and many include multiple engine names at once. This tool is useful for making sense of raw entries in server logs, verifying what environment a bug report actually came from, or understanding why analytics buckets certain visits as a particular device type.
HOW TO USE
- Copy a user agent string from a browser's devtools, a server log, or an analytics export.
- Paste it into the input field.
- Review the parsed breakdown of browser, version, OS, and device type.
- Compare against multiple UA strings if you're investigating a pattern across several log entries.
- Use the parsed device type to explain unexpected analytics or bug report behavior.
COMMON USE CASES
- A developer debugging a bug report by parsing the exact user agent a customer's browser sent to identify the real browser and OS version.
- Someone reviewing server access logs to understand what portion of traffic comes from mobile versus desktop.
- A QA engineer verifying that a device-detection script correctly identifies tablets versus phones.
- Someone investigating suspicious traffic by checking whether a user agent matches a known bot or crawler pattern rather than a real browser.
- A support engineer confirming a customer's reported Safari version actually matches what their browser sent, when troubleshooting a rendering issue.
TIPS & COMMON MISTAKES
- Nearly all browsers include Mozilla/5.0 at the start of their user agent for historical compatibility reasons, so its presence tells you nothing about which browser is actually in use.
- User agent strings are self-reported and easy to spoof - browser extensions, devtools, and scripts can override them, so treat parsed results as a strong hint, not a guaranteed fact, especially for security-sensitive decisions.
- Chrome-based browsers often include competitor engine names in their UA string for compatibility reasons - a Chrome UA typically mentions Safari too, which can be confusing if you're pattern-matching by hand.
- Newer browsers are increasingly shipping simplified or frozen user agent strings for privacy, so version-specific details may become less precise over time - don't build long-term critical logic around exact UA parsing.
MORE QUESTIONS
- Why does almost every user agent string contain the word Mozilla, even for Chrome or Safari?
- It's a historical artifact from the 1990s browser wars - sites once checked for Mozilla to serve enhanced content to Netscape, so other browsers started including it too for compatibility, and the convention stuck permanently even though it's now meaningless for identification.
- Can a user agent string be trusted for security decisions, like blocking bots?
- Not reliably - a UA string is just a header value the client controls, so anyone can send a fabricated one; real bot detection needs additional signals like request patterns or behavioral analysis.
- Why do some parsed results show an unclear or misidentified device type?
- Newer devices, unusual browsers, or user agents modified by privacy tools can fall outside recognized patterns, since parsing relies on matching known signatures rather than a universal standard format.
- What is user agent freezing and does it affect this tool's accuracy?
- Some browsers now report reduced or generalized OS and version details in their UA string as a privacy measure, meaning the parsed output may show a broader range instead of an exact version - this is a browser-side trend, not a limitation specific to this parser.