toon-format/toon

Health v2 · maintenance only

Adoption not part of the score

25261 stars · 1121 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

TOON (Token-Oriented Object Notation) is a compact, human-readable encoding of the JSON data model designed to reduce token usage in LLM prompts while remaining lossless and deterministic. It ships as a TypeScript SDK, a CLI, and benchmarks, with a shared spec and conformance suite across many language implementations.

Use cases

• reduce token costs when passing JSON data to LLM prompts
• encode uniform arrays of objects compactly for model input
• convert JSON to a more token-efficient format and back losslessly
• benchmark token efficiency of data formats for LLMs
• validate LLM output structure with explicit array lengths and field lists

When to choose

• your prompts embed large JSON payloads, especially uniform arrays of objects
• you want a lossless, deterministic JSON alternative optimized for token count
• you need a spec with multi-language implementations and conformance tests

When to avoid

• your data is deeply nested and heterogeneous, where JSON or YAML may be comparable
• you need a general-purpose serialization format for storage or APIs rather than LLM input
• your pipeline requires strict JSON tooling compatibility

Facets

library · maturity active

serialization llm-inference prompt-engineering cli benchmarking large-language-models developer-tools apis cli cross-platform data-format token-efficiency json-encoding llm-prompts tokenization data-engineering nodejs typescript

Member repositories

For agents

markdown · JSON · MCP: product_card(name="toon-format/toon")