User Agent
A user agent is a string your browser sends with every request that identifies the browser, its version, and the operating system to the website.
User Agent explained
The user agent is an HTTP header that announces what browser and OS you are using, for example Chrome on Windows or Safari on iOS. Sites read it to serve compatible layouts, decide mobile versus desktop views, and gather analytics.
In scraping and multi-accounting it is a basic but important signal. A user agent that does not match the rest of your fingerprint, such as a mobile string with a desktop screen size, is an easy tell for anti-bot systems, so it must stay consistent with every other attribute.
Examples
- 01A site serving a mobile layout after reading an iPhone user agent
- 02A scraper rotating realistic user agents to blend in
- 03An anti-bot flagging a headless-browser default user agent
Common use cases
Frequently asked questions
It is a header your browser sends that names the browser, its version, and the operating system, letting sites adapt content and collect analytics.
Default or missing user agents from automated tools are easy to detect. Realistic, rotating user agents that match the rest of your fingerprint help traffic blend in.
Yes, browsers and scraping libraries let you set it, but it must stay consistent with your other attributes or anti-bot systems will notice the mismatch.
No. It is only one of many fingerprint signals. Changing it alone does not stop tracking through canvas, WebGL, IP, and behavior.
Your browser, its version, your operating system, and sometimes device hints. Combined with other signals it contributes to a fuller fingerprint.
Ready to put this into practice?
See our independently-scored picks.