[cies]

One word answer: Types.

If you dont use a language with strong type safety the benefits are less.

For instance the OpenAPI3 (Swagger-NG) standard. It allows the typing/schema'ing of the JSON bodies. It also provides a bunch of generators[1] that can be used to generate client libs. And when the languages of the client libs permit it, those libs come with lots of type safety and greatly reduce boilerplate.

1: https://openapi-generator.tech/docs/generators/

[pbreit]

One of the reason I don't like types.

There really shouldn't be much boilerplate to passing JSON around back and forth.