# RustAPI TOON
**Token-Oriented Object Notation (TOON) support.**
## 🤖 What is TOON?
TOON is an experimental, density-optimized data format designed for **High-Volume LLM Interactions**.
When building agents or APIs that consume massive amounts of structured data via LLMs (GPT-4, Claude), standard JSON is token-expensive due to repeated keys and syntax overhead. TOON eliminates this redundancy.
## Comparison
**JSON (Expensive)**
```json
[
{"id": 1, "role": "admin", "active": true},
{"id": 2, "role": "user", "active": true},
{"id": 3, "role": "user", "active": false}
]
```
**TOON (Optimized)**
```
users[3]{id,role,active}:
1,admin,true
2,user,true
3,user,false
```
## Usage
RustAPI handles this transparently via content negotiation.
```rust
use rustapi_toon::Toon;
// Accepts explicit TOON or JSON automatically based on Content-Type
#[post("/ingest")]
async fn ingest(Toon(data): Toon<Vec<User>>) -> impl Responder {
// ...
}
```