What is this tool for?
It reads the information your browser makes available about itself and your device, and lays it out in one place – useful for debugging cross-browser issues, checking what a visitor's setup looks like, or just satisfying your curiosity about what websites can see.
Everything on this page is generated by JavaScript running in your own browser. Nothing is sent anywhere, so it's safe to leave open while you troubleshoot.
What is a user agent?
The user agent is a string your browser sends with every request, identifying itself, its version and your operating system. Websites and servers use it to decide what content or layout to serve, though it can be spoofed and shouldn't be relied on for anything security-critical.
Why do my CPU threads and device memory matter?
'CPU threads' (hardware concurrency) and 'device memory' give web apps a rough idea of how powerful your device is, so they can decide how much work to do at once – for example, whether to run a heavy calculation on the main thread or split it across workers. Not every browser reports these accurately, and some deliberately cap the values for privacy.
Why does 'do not track' say disabled even though I enabled it?
Do Not Track is a request a browser can send asking sites not to track you, but it's entirely voluntary – sites aren't obliged to honour it, and most major browsers have deprecated or removed the setting entirely, which is why it often shows as unsupported here.
Why might my screen resolution look different to what I expect?
The resolution reported here reflects your browser's viewport in CSS pixels, which can differ from your monitor's native resolution once display scaling, zoom level or high-DPI rendering are taken into account.
What can I use this information for?
- Debugging layout or compatibility issues on a specific browser
- Checking what device details a site could pick up during testing
- Confirming cookies, JavaScript or network connectivity are working
- Reporting your exact environment when raising a bug
Where's my IP address?
It isn't listed here, since it's provided by your network rather than your browser. Head to the IP address finder to see your public IPv4 and IPv6 addresses.
What are User-Agent Client Hints?
Client Hints (navigator.userAgentData) are Chromium's newer, more private replacement for reading the user agent string – sites ask for exactly the details they need instead of parsing a string that reveals everything by default. Firefox and Safari haven't adopted it, so those rows show as unsupported.
What do 'colour scheme' and 'reduced motion' preference mean?
These reflect accessibility and display settings from your operating system – whether you've chosen a dark or light theme, and whether you've asked for animations to be kept to a minimum. Well-built sites read these to match your system rather than forcing their own defaults on you.