I Replaced JSON with TOON in My LLM Prompts and...

Hey! I'm Andrey, a frontend developer at Cloud.ru, and I write about frontend and AI on my blog and Telegram channel. I work with LLM APIs every day. And every day I send structured data into context: product lists, logs, users, metrics. All of it - JSON. All of it - money. At some point I calculated how many tokens in my prompts go to curly braces, quotes, and repeated keys. Turns out - a lot. Way too much. Then I tried TOON. Here's what happened. The Problem: JSON Is a Generous Format Take a t