At DuckDuckGo, we don't track you, ever. That's our Privacy Policy in a nutshell. To make sure DuckDuckGo Search is reliable, we use a browser feature called Network Error Logging (NEL) to learn about connection problems without collecting any personal information.
What is Network Error Logging?
Network Error Logging is a W3C web standard that lets websites ask web browsers to automatically report network connection problems. When you visit DuckDuckGo, your browser may receive an HTTP header called NEL that tells it where to send these reports if something goes wrong with the connection. Reports are sent to the *.nel.duckduckgo.com domain.
How we monitor connection errors
NEL reports sent to DuckDuckGo contain only technical information about the network connection itself. They typically include the type of error that occurred (for example, a DNS resolution failure, TCP connection timeout, or TLS certificate error), the HTTP status code your browser received, how long the connection attempt took before failing, and at what stage the error happened (for example, during DNS lookup, the TLS handshake, or while waiting for a response).
How we ensure no personal information is collected
NEL reports sent to DuckDuckGo contain no user agents, no client IP addresses, no cookies, and nothing that could identify who you are. We take deliberate steps to ensure this:
- We strip query parameters from URLs and referrers when we receive reports and never store them. This means your search queries are never captured in these logs.
- No user agent information. NEL reports do not include your browser's User-Agent string, so we cannot tell what browser, operating system, or device you are using.
- No cookies or session data. NEL reports are sent by the browser as a separate, anonymous request. They do not carry your cookies, authentication tokens, or any other session information.
- No IP address storage. While any network request inherently involves an IP address during transit, we do not log or store IP addresses associated with incoming NEL reports.
We also limit how much data is collected in the first place. Our NEL policy includes a sampling fraction parameter that tells your browser to only send a report for a small, random subset of requests. This gives us enough statistical signal to detect widespread problems while keeping data collection to a minimum. The browser decides randomly whether each request falls within the sample, so there is no way for us to target or identify specific users through sampling.
Why does DuckDuckGo use NEL?
As a search engine, it's critical that users can reach DuckDuckGo reliably. Connection problems, like DNS failures or TLS errors, can prevent you from accessing DuckDuckGo, and they are often invisible to us because the connection never reaches our servers.
NEL gives us visibility into these problems from the browser's perspective, allowing us to detect regional outages or DNS issues, identify misconfigured network infrastructure, measure the overall reliability of connections to DuckDuckGo, and respond faster to connectivity incidents.
Without NEL, we would have no way of knowing that connections may be failing before reaching our servers.
How does this relate to improving.duckduckgo.com?
You may already be familiar with improving.duckduckgo.com, which we use to anonymously test and improve DuckDuckGo's products (learn more here). NEL serves a different purpose: instead of measuring product usage, it monitors the health of the network connection between web browsers and our servers Both systems are designed with the same principle – we get the information we need to improve our service without ever collecting any personally identifiable information.
If you have any concerns, please feel free to contact us.