I built SLIM because JSON wastes tokens on repeated keys. Every object in an array repeats "id", "name", "email"...
SLIM defines the schema once, then just data rows:
JSON: {"id":1,"name":"Alice"},{"id":2,"name":"Bob"} SLIM: |id#,name$|1,Alice|2,Bob
Results: 50%+ token savings, still human-readable, LLMs understand it without parsing.
MIT licensed, zero dependencies, TypeScript.
Would love feedback from the HN community.