Site Improvements (&atb=, /t/)

At DuckDuckGo, we do not collect or share any personal information at all. That's our privacy policy in a nutshell. We have no IP addresses in our logs, and we do not create unique cookies. That means we do not even have the capability to create search histories or search sessions for any individual — privacy by design.

At the same time, we need a way to reliably improve our site for our users in an anonymous way. You might notice that when you search DuckDuckGo, there may be an "&atb=" URL parameter in the web address at the top of your browser. This parameter is a method we developed to help us anonymously A/B (split) test experience changes we make to DuckDuckGo. For example, we may show one spelling message to the A version and another to the B version, and then check statistically which message version gets more engagement.

We also measure engagement for these experiments by sending an anonymous request when specific events happen on the page (e.g. the spelling message is clicked). If you are looking at network requests, these are the ones going to the one-pixel image at There is no personally identifiable information in these requests. They are encrypted, and go directly to DuckDuckGo. In accordance with our privacy promise, we don't log IP addresses, and are therefore unable to associate these requests with individual users.

To reiterate, we cannot ever tell what individual people are doing since everyone is anonymous, and that is a limit of our statistical methods since we are private by design. We can, however, within this anonymous limitation, reliably determine what changes are generally working, using this anonymous aggregate method.

The &atb= parameter, our engagement (/t/) requests, and more importantly your search parameter (?q=), are all fully encrypted in transit to DuckDuckGo. This means nobody else but us can see them.

We have developed these systems from scratch, instead of using third-party services, because of our privacy promise to never collect or share any personal information. We're proud to be able to improve our site for you in a completely anonymous way!

If you have any concerns, please feel free to reach out to us directly at