devpack
Site Audit

User Agent Parser

Decode any User-Agent string into browser, engine, operating system and device — and find out whether it belongs to a search engine, AI crawler or script.

Runs in your browser
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Browser
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Operating system
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Device type
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Rendering engine
Details
Browser
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JSON
{}

Your data never leaves your computer. All processing happens 100% locally in your browser.

How to use the User Agent Parser

  1. Your own user agent is loaded automatically. To analyse another one, paste it into the box — e.g. from a server log or analytics export.
  2. Or pick an entry from Load a sample to see how Googlebot, GPTBot, an iPhone or a smart TV identify themselves.
  3. Read the browser, OS, device type and engine in the summary cards; the details panel adds versions, vendor, model and CPU architecture.
  4. If the string belongs to a crawler, a banner names the bot and its operator. Copy the JSON result to use it in your code or tickets.

What is a user agent string?

A user agent (UA) string is the text a browser or HTTP client sends in the User-Agent request header to identify itself. Servers use it for analytics, bug workarounds, bot management and serving the right download. A typical Chrome on Windows string looks like this:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

It is full of historical baggage: every browser claims to be “Mozilla/5.0”, Chrome mentions Safari and Gecko, and Edge adds Edg/ to Chrome’s string. That’s why reliable parsing has to check tokens in the right order — Edge before Chrome, Chrome before Safari.

How this parser works

  • Bots first: dozens of crawler tokens are matched — search engines (Googlebot, Bingbot, YandexBot, Applebot), AI crawlers (GPTBot, OAI-SearchBot, ClaudeBot, PerplexityBot, CCBot, Bytespider), social previews (facebookexternalhit, Twitterbot, Slackbot), SEO tools and HTTP libraries (curl, python-requests, Go-http-client).
  • Browser: specific browsers (Edge, Opera, Samsung Internet, Vivaldi, Yandex, in-app browsers) are checked before the generic Chrome, Firefox and Safari tokens.
  • Engine: Blink for Chromium browsers, Gecko for Firefox, WebKit for Safari — and for every browser on iOS, because Apple requires WebKit there (outside the EU).
  • OS & device: Windows NT versions are mapped to names, iOS/Android versions are extracted, and the device type comes from tokens like Mobile, iPad or SMART-TV.

Limits of user agent detection

Browsers now “freeze” parts of the string for privacy. Chrome reports minor versions as .0.0.0, Android Chrome sends Android 10; K instead of the real version and model, Windows 11 still says Windows NT 10.0, and Safari reports macOS as 10_15_7. Accurate values are only available through User-Agent Client Hints (Sec-CH-UA-* headers or navigator.userAgentData), which this tool also reads for your own browser. And any client can send any string, so never use the UA for security decisions.

Verifying real Googlebot traffic

Scrapers often pretend to be Googlebot. To verify, do a reverse DNS lookup of the visitor’s IP (it should end in googlebot.com, google.com or googleusercontent.com) and then a forward lookup of that hostname, which must return the same IP. You can run both with our DNS Lookup. To check which AI crawlers your robots.txt allows, use the AI Crawler Checker.

Tools that pair well with the User Agent Parser

  • What Is My IP — Your public IP address and everything your browser reveals to the websites you visit — user agent, screen, language, timezone and request headers.
  • Robots.txt Tester — Check whether a URL is allowed or blocked for Googlebot, Bingbot, GPTBot and other crawlers, see exactly which rule matched, and edit the file to test changes before you deploy them.
  • HTTP Header Checker — Fetch any URL and see exactly what the server sends back — status code, redirect chain and every response header, with a plain-English explanation of the ones that matter for SEO, caching and security.
  • SSL Checker — Verify an HTTPS certificate in seconds — see when it expires, who issued it, which hostnames it covers and whether the chain is trusted.

Frequently asked questions

What is my user agent?
It is loaded into the box automatically when you open this page. Click Use my user agent to reload it after editing the field.
Why does Chrome’s user agent mention Safari and Mozilla?
For compatibility. Early websites served advanced features only to “Mozilla” browsers, so every browser copied the token; Chrome later inherited “AppleWebKit … Safari” from its WebKit roots. Sites that sniff UAs would break if these tokens were removed.
Can I detect Windows 11 from the user agent?
No. Windows 10 and 11 both send Windows NT 10.0. Use the Sec-CH-UA-Platform-Version client hint instead — values of 13 or higher mean Windows 11.
How do I identify AI crawlers like GPTBot or ClaudeBot?
Their user agents contain tokens such as GPTBot, OAI-SearchBot, ChatGPT-User, ClaudeBot, PerplexityBot or CCBot. Paste a log line here to identify it, and control their access in robots.txt.
Should I use the user agent for feature detection?
No — check for the feature itself (e.g. 'share' in navigator or CSS @supports). UA sniffing breaks when browsers update or spoof strings; use it for analytics and bot handling only.

Related tools

What Is My IPYour public IP address and everything your browser reveals to the websites you visit — user agent, screen,…AI Crawler CheckerSee which AI bots — from OpenAI, Anthropic, Google, Perplexity, Apple, Meta and others — your robots.txt…Robots.txt TesterCheck whether a URL is allowed or blocked for Googlebot, Bingbot, GPTBot and other crawlers, see exactly…HTTP Header CheckerFetch any URL and see exactly what the server sends back — status code, redirect chain and every response…DNS LookupQuery all common DNS record types for a domain in one go, with TTLs, sorted MX records and an SPF/DMARC…SSL CheckerVerify an HTTPS certificate in seconds — see when it expires, who issued it, which hostnames it covers and…