Benchmarking DNS resolvers on Android

Have you ever wondered which DNS resolver is the closest to your location?

There is an Android app called DNS Speed Test that I have been using for a long time that allows to make latency tests on the go.

As you can see here in Seoul Cloudflare is by far the fastest, since I hit the Seoul PoP.

For some reason Google makes me go through North America according to traceroute/mtr, hence the difference. I checked on gcping.com and it's the same for the closest location, Tokyo, which has a huge 50 ms latency...

However, the latency doesn't matter that much for mobile devices. I've been using the DNS-over-TLS resolvers from AdGuard, which as you can see are more than 200 ms from me, and it's perfectly fine. These latency tests are still interesting though!