toon and tonl
These are direct competitors: both are JSON-based serialization formats designed to optimize token efficiency for LLM prompts, offering similar functionality with different implementation approaches.
About toon
toon-format/toon
🎒 Token-Oriented Object Notation (TOON) – Compact, human-readable, schema-aware JSON for LLM prompts. Spec, benchmarks, TypeScript SDK.
Combines YAML-style indentation with CSV-like tabular layouts for uniform arrays, achieving ~40% token savings over JSON while maintaining lossless round-trip conversion. The format uses explicit array-length declarations `[N]` and field headers `{fields}` to provide LLMs with clear schema boundaries, improving both parsing accuracy (74% vs JSON's 70%) and reliability. Spec-driven with implementations across TypeScript, Python, Go, Rust, and .NET, designed as a translation layer between JSON-based application logic and token-efficient LLM input.
About tonl
tonl-dev/tonl
TONL (Token-Optimized Notation Language)
Combines compact binary-efficient serialization with JSONPath-style querying, aggregation, and fuzzy/temporal search capabilities—all targeting LLM token reduction (up to 60% smaller than JSON). Built as a zero-dependency TypeScript library with 698 passing tests, it offers both a document API for data manipulation and CLI tools for encoding, validation, and interactive analysis across Node.js and browsers (10.5 KB gzipped).
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