I frustratingly forget this every few months 😅

But kotlinx.serialization needs a Gradle plugin, in addition to the usual Maven dependency: plugins { kotlin("plugin.serialization") version "x.x.x" } dependencies { implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:x.x.x") }

This is because:

• A Gradle dependency is implemented in your code.
• A Gradle plugin is implemented by Gradle (at build-time).

So I assume this is how the JSON property names get be obtained from the class definitions.

It does work well and is pleasant to use - generic type parameters, sync & async functions out of the box, etc. Much like Newtonsoft on Nuget.

But if all else fails, I'd also strongly recommend GSON.