Hello and thank you for your comment.

Benchmarks are hard: it's difficult to measure exactly what you want, and you need to take things like warmup into account (Moshi pays an initial cost when creating adapters the first time, then they are cached).

I keep an eye on kotlinx.serialization and I'm interested in using it some day, but I wish it supported streaming. Currently it only transforms strings to objects which is not suitable for big JSON responses in my opinion.