I skimmed over what is available, please note i didn't try it myself, beyond setting it up and digging at it with the usual tools. You can pry the mullvad dns out of my cold dead hands. Also, I'm just a dude with a mouse and keyboard. Doing your own research is always recommended.
Privacyguides.org seem to have checked them out. From what I can gather by reading their privacy policy, it seems promising.
- its open source
- they claim to not save logs unless you ask them to do so by paying
- small, 3-human operation
- they seem to aim for anonymity
There do seem to be some caveats.
- they store data in the US, so they are liable to turn over any logs they will have to authorities, if asked by a court-order. They did however mention, that they have no recourse for now, but might change in the future.
- their dns-over-https and recursive dns-over-https, services use 3rd parties like cloudflare and fly.io. Do with that information what you may. In my eyes a bit of a liability - but they do mention that they anonymize the data.
From what I can test with dig and kdig on my end, they provide what they claim.
That being said, this service is likely better than using cloudflare or google dns, that much is for sure. Their git seems to have slowed down a fair bit since the summer of 2024. Latest release being in June of 2024, not what I would want to see for an application that is in early stages, version 0.5, that is the app that would handle my dns.
TL;DR - My personal 2-cents, is that you can do better. quad9 is going to be a better choice.