How to read a user agent string
- The box starts with your own browser's user agent. Paste a different one from a log file or a bug report to replace it.
- Read the browser, rendering engine, operating system, device type, vendor and model, and the bot check below it.
- Copy any value with its copy button. Use "Try a sample" to see how phones, tablets, TVs, and crawlers look.
User agent strings are not standardized and can be changed by the user, so treat the result as a good guess. Chrome now freezes parts of the string (for example, the Android model and OS version), which is why the Client Hints section can show more detail.
Questions
Is my user agent sent anywhere?
No. Your browser already knows its user agent, and the tool parses it locally with a small JavaScript library. Nothing is uploaded or logged.
What is a user agent string?
It is a line of text your browser sends with every request, describing the browser, rendering engine, operating system, and sometimes the device. Websites and servers use it to adapt content and to recognize crawlers.
Why does every user agent start with Mozilla/5.0?
It is a historical leftover. Early browsers copied each other's strings so websites would serve them the full version of the page, and the prefix stuck. Look at the parts after it for the real details.
What are Client Hints and why are they empty on my browser?
Client Hints (navigator.userAgentData) are a newer, structured way to read the same details without parsing a string. Chrome, Edge, and Opera support them. Firefox and Safari do not, so that section stays empty there.
How accurate is bot detection?
It recognizes the common crawlers and tools that announce themselves, such as Googlebot, Bingbot, and curl. A bot that pretends to be a normal browser cannot be told apart from the string alone.
Credits
Built on Bowser (MIT). OneTooling is not affiliated with that project.