I have a basic Body interface that I use for all m...

# serialization

[zt]

I have a basic Body interface that I use for all my API requests

@Serializable
internal sealed interface Body {
    val context: ApiContext
}

The problem is that when serializing, it also adds the type field assuming its using polymorphism but I don't want it to do that.

[CLOVIS]

If it's an interface, it needs the type discriminator—otherwise, how would it know which implementation of the interface to use?

If you serialize and deserialize concrete subclasses of Body , it will not add the type .