Quick answer
The tool reads your browser's User-Agent as soon as the page opens; paste any other string (from server logs or analytics) to see the browser and version, rendering engine, operating system, device type, vendor / model, whether it is a bot (Googlebot, Bingbot, AI crawlers, link-preview bots…) or an in-app browser such as Facebook, Instagram or TikTok. Everything runs in your browser.
What is a User-Agent?
A User-Agent is the string a browser, app or bot sends with every request to introduce itself. It is long, hard to read and full of “Mozilla/5.0” and “like Gecko” for historical reasons. This parser turns it into plain information, recognises major browsers (Chrome, Safari, Edge, Firefox, Samsung Internet, Opera…), in-app browsers in Facebook, Instagram or TikTok, and dozens of search, ads, AI and SEO bots. Handy for reading logs, debugging a layout bug that only one device hits, or filtering bot traffic.
How to parse a User-Agent
- 1
Open the page: the input is filled with your current browser's User-Agent and the result appears right away.
- 2
To analyse another string, paste it (for example a line from an nginx access.log) or pick a sample.
- 3
Read the result: browser, engine, OS, device type, vendor / model, bot and in-app browser.
- 4
On Chrome, Edge or Opera, check the Client Hints section for a more precise OS version and model.
- 5
Press “Use my User-Agent” to go back to your own browser's string.
Reading the parts of a User-Agent
| Part of the string | Means | Note |
|---|---|---|
| Mozilla/5.0 | Historical prefix almost every browser sends | Tells you nothing about the browser |
| (Windows NT 10.0; Win64; x64) | 64-bit Windows | Windows 11 still says NT 10.0, so it can't be told apart from Windows 10 here |
| (Macintosh; Intel Mac OS X 10_15_7) | A Mac | Browsers freeze 10_15_7, even on newer macOS and Apple-silicon Macs |
| (iPhone; CPU iPhone OS 17_5 like Mac OS X) | iPhone on iOS 17.5 | Browsers on iOS use Safari's WebKit |
| AppleWebKit/537.36 (KHTML, like Gecko) | WebKit / Blink engine | Chrome and Edge send this even though they use Blink |
| Chrome/126.0.0.0 | Chrome version | Reduced: only the major number is real, the rest are zeros |
| Mobile | Phone version of the browser | Android tablets usually omit Mobile |
Bots you often see in logs
| Name in the string | Owner | Purpose |
|---|---|---|
| Googlebot | Search indexing | |
| bingbot | Microsoft | Search indexing |
| YandexBot | Yandex | Search indexing |
| facebookexternalhit | Meta | Fetching title and image for shared links |
| GPTBot, ClaudeBot, PerplexityBot | OpenAI, Anthropic, Perplexity | Collecting data for AI |
| AhrefsBot, SemrushBot | Ahrefs, Semrush | SEO and backlink tools |
| curl, python-requests | Tools / libraries | Scripts and monitoring |
Bots can fake their User-Agent. To confirm a real Googlebot, do a reverse DNS lookup: the name must end in googlebot.com or google.com and resolve back to the same IP.
Worked examples
A customer reports a bug from a Facebook link
The string contains “FBAN” or “FB_IAB”: it is Facebook's in-app browser (WebView), not Chrome or Safari. Downloads and Google sign-in are often restricted there.
Odd requests in the log
Paste a line from access.log: “GPTBot · OpenAI · AI data collection”. To block it, add User-agent: GPTBot with Disallow: / to robots.txt.
A layout bug on one device only
The customer's User-Agent shows Safari 15 on iOS 15. Knowing the old version, you can check which CSS / JavaScript features it lacks.
What browser am I using?
Open the page and see it straight away, e.g. “Edge 130 · Blink · Windows 10 / 11 · Desktop”, handy when support asks.
Common problems
- Trying to tell Windows 10 from Windows 11 via the User-Agent.
- Not possible: both say Windows NT 10.0. On Chrome / Edge, check “Platform version” in Client Hints (13 or higher means Windows 11).
- Trusting the User-Agent to allow or block.
- The sender writes it and can change it trivially. Combine it with IP checks, reverse DNS or authentication.
- Seeing “Safari” in a Chrome string and assuming Safari.
- Chrome and Edge add “Safari/537.36” for compatibility. The parser looks for specific markers first (Edg/, OPR/, Chrome/) before Safari.
- Chrome on iPhone shows the WebKit engine.
- That's correct: on iOS, Chrome (CriOS), Firefox (FxiOS) and others use Safari's WebKit under Apple's rules.
Why User-Agents carry less information now
To reduce fingerprinting, Chrome reduced its User-Agent: minor version numbers became 0.0.0 and the Android version and device model were frozen. Detailed data moved to User-Agent Client Hints (the Sec-CH-UA-* headers), sent only when a site asks.
That is why the tool also shows Client Hints when your browser supports them (Chrome, Edge, Opera and other Chromium browsers). Safari and Firefox don't support Client Hints yet.
Privacy
Your User-Agent and Client Hints are read in the browser; strings you paste are never sent anywhere.
Glossary
- User-Agent
- The string identifying the software making a request, sent in the HTTP User-Agent header.
- Rendering engine
- The part that draws web pages: Blink (Chrome, Edge), WebKit (Safari), Gecko (Firefox).
- WebView
- A browser embedded in an app (Facebook, Instagram…), often with limited features.
- Client Hints
- Sec-CH-UA-* headers carrying more detailed browser data when a site requests it.
- Crawler / bot
- An automated program that reads web pages, such as a search engine bot.
Frequently asked questions
What is my User-Agent?
Open this page and the input shows your browser's exact User-Agent along with the parsed result. Copy it to send to support.
How do I verify a real Googlebot visit?
Do a reverse DNS lookup: the name must belong to googlebot.com or google.com, and a forward lookup of that name must return the same IP. A “Googlebot” User-Agent alone proves nothing.
Why can't I see the exact Samsung model?
Chrome on Android replaces the model with “K” in the User-Agent. The real model is only available via Client Hints when the browser allows it.
Does it detect in-app browsers?
Yes. It recognises Facebook, Messenger, Instagram, TikTok, LINE, Zalo and several other apps from markers in the string.
Is my User-Agent sent to a server?
No. Parsing happens entirely in your browser.
Can I block AI bots?
Major AI crawlers (GPTBot, ClaudeBot, Google-Extended…) respect robots.txt. Add a matching User-agent group with Disallow: / to opt out.
Ratings and comments
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