XRON — open source

XRON is a lossless data serialisation format that reduces JSON LLM token consumption by up to 80 per cent. It is open source and written entirely in TypeScript.

The problem

JSON was designed for parsers and people, not per-token pricing. Every repeated key, brace and quote mark costs tokens that carry no information the model needs — and in agent systems that pass structured data through a model many times per task, the overhead compounds into real cost and exhausted context windows.

The format

XRON keeps every byte of information — lossless is the operative word — while stripping the redundancy. It is lightweight and fast, built to optimise context-window usage and reduce GPT and Claude costs for agents and multi-agent systems operating over long conversations.

The repository is public on GitHub. For anyone running multi-step LLM workflows over structured data, the maths is simple: the same information at a fraction of the tokens.