Chevrotain / chevrotain

Parser Building Toolkit for JavaScript

niieani / gpt-tokenizer

The fastest JavaScript BPE Tokenizer Encoder Decoder for OpenAI's GPT models (gpt-5, gpt-o*, gpt-4o, etc.). Port of OpenAI's tiktoken with additional features.

OpenLlamas / model-xray

Model authenticity / dilution detection CLI: one command, one report. Detect fake or watered-down LLM endpoints via identity, context, tokenizer, capability and latency checks.

SergeevDmitry / llm-kit

Small, independent TypeScript packages for LLM plumbing — token budgets, streaming JSON repair, cost accounting, retries, embedding caches. No provider SDKs.