​​KDL is a document language with xml-like semantics that looks like you're invoking a bunch of CLI commands! It's meant to be used both as a serialization format and a configuration language, much like JSON, YAML, or XML.

Features:
- Node-based, you won't have to mess with identation to make it work
- Type annotations
- Implementations in different languages: #python, #elixir, #rust, #java, #js, #ruby, #php, etc

https://kdl.dev/