Quad9 9.9.9.9
Security and privacy. The strongest of the major resolvers on both axes.
Official siteAbout Quad9
Quad9 launched in 2017 as a partnership between IBM, Packet Clearing House, and the Global Cyber Alliance, and was later spun out as the Quad9 Foundation, a Swiss non-profit. Switzerland was chosen specifically because its data protection laws are among the strongest in the world, and the foundation is structured so that no single party can unilaterally compel disclosure of user data.
The default 9.9.9.9 endpoint blocks domains that appear on threat-intelligence feeds — primarily malware, phishing, and command-and-control infrastructure. Block decisions are made automatically against a multi-source feed; there is no manual editorial filtering or content-based blocking. A 9.9.9.10 endpoint is available for users who want unfiltered resolution.
Quad9 retains no personal data. There is no IP-level logging, no query-level logging tied to a user, and the foundation publishes regular transparency reports. The trade-off is performance: Quad9's anycast network is large but not as dense as Cloudflare's, so resolution can be slightly slower in some regions. For most users that delta is negligible.