What is a User Agent?
Updated at: Jun 25, 2024
A user agent is a relatively short bit of text that (attempts to) describe the Software/Browser (the "Agent") that is making the request to a website. Web browsers include the user agent string in the requests they make to websites. The User Agent often includes descriptions of the Operating System and Device Type that the Browser/Agent is running on.
User Agents usually look quite strange
User agents aren't intended for "normal" internet users to look at or deal with, and there is a long and complicated legacy behind the format of a lot of popular user agents, which further complicates things.
User Agents tell a website what browser you are using
So every time you load a web page, image, video, or song in your web browser, your browser makes a "request" for that file. Included in that request is the user agent (In a HTTP Header). Web sites can look at that user agent string and determine what web browser, operating system, and device you are using.
Are user agents personally identifying?
No, user agent strings aren't normally "personally identifying"; knowing someone's user agent is a bit like knowing the model and color of the car they drive - unless you've intentionally made a very unique one, lots of other people will have the same one as well, so a user agent by itself it can't be used to identify you. However, along with a combination of other pieces of information, such as your IP Address, Geographic location, the times of your requests, the patterns of your requests, and so on, it can be possible to identify your traffic.
- It's how we tell you "my browser" on our homepage!
- We've written some guides to change your user agent
- We have a huge listing of user agents if you want to explore the different types
- If you're a software developer, our User Agent Parsing API can help you decode your visitors user agents.
