toon
A compact, human-readable data format (TOON) that represents JSON more cheaply for LLM prompts. It comes with a TypeScript SDK, a CLI and benchmarks, and aims to cut token use.
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Share on XLicense: MIT
Overview
TOON, short for Token-Oriented Object Notation, is a compact and readable way to write the JSON data model, designed to use fewer tokens in LLM prompts. It mixes YAML-style indentation for nested objects with CSV-style tables for uniform data. The idea is to keep JSON in your program and encode it as TOON only when sending it to a model. The repository has a TypeScript SDK, a CLI and benchmarks.
Key features
- Lossless encoding of JSON data for LLM input
- Indentation for nesting, table form for uniform arrays
- TypeScript SDK and command-line tool
- Benchmarks included
Best for
Developers who send lists of similar records to LLMs and want to trim token use. The README says deeply nested or non-uniform data may be more efficient as JSON.
- Upstream
- toon-format/toon
- Fork on GitHub
- Guo-astro/toon
- Upstream stars
- 25k
- Category
- Developer tools and infrastructure
- Language
- TypeScript
- License
- MIT
- Forked
- 2025-11-09
- Sync status
- In syncLast synced 2026-10-19
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