Browser Tools
What is my User-Agent?
See the raw User-Agent string your browser sends, and what it says about your setup.
Your User-Agent string
Reading…
What it means
- Browser
- —
- Browser version
- —
- Operating system
- —
- Device type
- —
- Platform
- —
- Automated client
- —
Parsed entirely in your browser. Nothing on this page is sent to our servers.
What a User-Agent string actually contains
Take a typical desktop Chrome User-Agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko)
Chrome/131.0.0.0 Safari/537.36
Each token has a job, and most of them are historical baggage:
- Mozilla/5.0 — a compatibility token every browser sends. It carries no real information.
- (Macintosh; Intel Mac OS X 10_15_7) — the platform. Note that macOS has reported 10_15_7 regardless of actual version since Big Sur, deliberately, to reduce fingerprinting.
- AppleWebKit/537.36 (KHTML, like Gecko) — the rendering engine lineage, frozen years ago.
- Chrome/131.0.0.0 — the part that is genuinely informative. Minor version digits are zeroed on purpose.
- Safari/537.36 — another compatibility claim, not an indication that Safari is involved.
Why User-Agent detection is unreliable
The string is supplied by the client, so it is a claim rather than a fact. Anyone can change it in one line of configuration, and plenty of software does — privacy extensions, corporate proxies, crawlers imitating browsers, and testing tools all rewrite it routinely.
This is why feature detection has replaced browser detection in good front-end practice. Ask whether the capability you need exists rather than guessing from a name and version. Reserve the User-Agent for analytics, debugging and coarse decisions where being wrong is harmless.
User-Agent Client Hints
Chromium browsers now expose the same information through a structured mechanism instead. Low-entropy values such as the browser brand and whether the device is mobile are sent by default; anything more specific — full version, platform version, model — has to be requested explicitly by the server. The result is that sites which genuinely need detail can ask for it, while passive fingerprinting gets meaningfully harder.
User-Agents and privacy
Your User-Agent is one input to a browser fingerprint: combined with your screen size, timezone, language and installed fonts, it can identify a browser without any cookie at all. See exactly what your browser exposes on the browser info page.
The counterintuitive part is that trying to hide can make you easier to track. A common, unmodified User-Agent blends into millions of others. A rare or self-contradictory one — claiming Windows while exposing macOS font metrics, say — stands out immediately.
Frequently asked questions
What is a User-Agent string?
A User-Agent is a line of text your browser sends with every request, describing itself and the platform it runs on. Servers use it to decide things like whether to send a mobile layout or which download to offer. It is self-reported, so it can be changed or faked at will.
Why does my User-Agent mention browsers I do not use?
For historical compatibility. Almost every User-Agent begins with "Mozilla/5.0" because 1990s servers checked for it before serving modern pages, and browsers have never been able to drop it. Chrome also claims to be Safari and KHTML, and Edge claims to be Chrome, for the same reason: nobody can afford to be excluded by a badly written server check.
Can I change my User-Agent?
Yes. Browser developer tools let you override it per session, and extensions can rotate it automatically. Bear in mind that a rare User-Agent makes you more identifiable rather than less, because it becomes a distinguishing signal in a browser fingerprint.
Is the User-Agent being phased out?
It is being frozen rather than removed. Chromium browsers now report reduced detail and offer User-Agent Client Hints as a structured replacement, where a site must explicitly ask for specific fields. Expect the string to keep existing but to become progressively less specific.