User Agent Parser - Identify Browser, OS & Device

Parse any user agent string to identify the browser, rendering engine, operating system, and device type. Your own user agent is loaded automatically. Free and fully in-browser.

User Agent Parser - Decode Browser Identification Strings

Every browser, app, and crawler announces itself with a user agent string, and this tool translates that cryptic line into plain facts: which browser and version, which rendering engine, which operating system, and whether the client is a desktop, phone, tablet, or bot. Your own user agent is filled in automatically when the page loads, and you can paste any other string to analyze it.

Web developers paste user agents from bug reports to reproduce browser-specific issues. Support teams use it to figure out what a customer is actually running when screenshots are not available. Analysts checking server logs identify which entries come from Googlebot, Bingbot, or SEO crawlers versus real visitors, and QA engineers verify that device-detection logic classifies clients correctly.

User agent strings are notoriously misleading by design: nearly every modern browser claims to be Mozilla/5.0, Chrome includes the word Safari, and Edge includes both Chrome and Safari. Reliable parsing therefore checks the most specific markers first: Edg/ for Edge, OPR/ for Opera, SamsungBrowser/ for Samsung Internet, then Chrome, Firefox, and finally Safari, which is identified by its Version/ token. This parser applies that ordered ruleset along with bot signatures for a dozen common crawlers.

Note that user agents are trivially spoofed and are being reduced: Chrome froze parts of its UA string and modern feature detection plus User-Agent Client Hints are preferred for adapting sites. Treat parsed results as a strong hint, not proof, especially for analytics or security decisions.

The copy-as-JSON button exports the parsed result for use in test fixtures or documentation. For related debugging, our JWT Decoder helps inspect auth tokens from the same request logs, and the .htaccess Redirect Generator helps when you need to route legacy mobile URLs.

How the User Agent Parser Works

  1. 01Your own browser's user agent loads into the input automatically when the page opens.
  2. 02Paste any other user agent string to analyze it instead - from logs, bug reports, or analytics.
  3. 03An ordered ruleset checks bot signatures first, then browser markers from most to least specific.
  4. 04Read the results as labeled cards and copy the parsed structure as JSON.

Reading User Agent Strings Correctly

Paste the string exactly as it appears in your server log or bug report; the parser is whitespace tolerant and case aware where it matters. The detection order is the key to accuracy. Bots are checked first, because crawlers like Googlebot embed Chrome-like tokens that would otherwise be misread as real browsers. Then come the browsers that wrap Chromium and must be identified before Chrome itself: Edge by its Edg token, Opera by OPR, and Samsung Internet by SamsungBrowser. Firefox and Chrome follow, and Safari is checked last because nearly every WebKit browser includes the word Safari - genuine Safari is recognized by its Version token. Operating system detection maps Windows NT numbers to marketing names (NT 10.0 covers both Windows 10 and 11, which share the token), converts iOS and macOS underscore versions to dotted form, and recognizes Android, ChromeOS, and Linux. Device classification distinguishes tablets (iPad, or Android without the Mobile token) from phones and desktops. The JSON export gives you the same structure programmatically, ready for test fixtures or documentation.

When to Use the User Agent Parser

Use it when a bug report includes a user agent and you need to know what the reporter was actually running, when triaging server logs to separate crawler traffic from human visitors, or when verifying that your device-detection or analytics code classifies clients correctly. It is also useful for checking what your own browser advertises about itself. For runtime feature decisions in production code, prefer feature detection over user agent sniffing.

Common Use Cases

  • Decoding the user agent attached to a customer bug report
  • Separating search engine and SEO crawler hits from human traffic in server logs
  • Verifying device-detection logic against real-world user agent samples
  • Exporting parsed results as JSON for test fixtures
  • Inspecting auth tokens from the same request logs JWT Decoder - Inspect Tokens Instantly

Expert Tips

  • For feature decisions in production code, use feature detection or User-Agent Client Hints; string parsing is for diagnostics, not branching logic.
  • When log entries claim to be Googlebot, verify with a reverse DNS lookup - fake Googlebot user agents are a common scraper disguise.
  • Keep a few real user agent samples from your analytics as regression fixtures whenever you change detection code.

Frequently Asked Questions

Why do all user agents start with Mozilla/5.0?→
Historical compatibility. In the 1990s servers sent better content to Netscape (Mozilla), so every later browser claimed the token to avoid being served degraded pages. It has been meaningless boilerplate ever since.
Why does Chrome's user agent contain Safari?→
Chrome originally used WebKit, Safari's engine, and kept the Safari token for compatibility. That is why parsers must check for Chrome, Edge, and Opera markers before concluding a string is Safari.
Can I trust a user agent to identify a visitor?→
No. User agents are trivially spoofed - curl, scrapers, and privacy tools set arbitrary strings. Treat the parsed result as a hint for debugging and analytics, never as a security control.
Which bots does the parser recognize?→
Googlebot, Bingbot, DuckDuckBot, YandexBot, Baiduspider, Applebot, AhrefsBot, SemrushBot, GPTBot, ClaudeBot, the Facebook and Twitter link crawlers, Slackbot, and a generic fallback for anything containing bot, crawler, or spider.

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