TOON vs JSON: A Comprehensive Comparison for LLM Applications

When building LLM applications, choosing the right data format can significantly impact your costs, performance, and user experience. Let's compare TOON and JSON formats to help you make the best decision.

Format Overview

JSON (JavaScript Object Notation)

• Industry standard for data interchange
• Human-readable and widely supported
• Verbose with many structural characters
• High token consumption

TOON (Token-Oriented Object Notation)

• Designed specifically for LLM applications
• Compact and token-efficient
• Maintains data structure clarity
• Up to 60% token reduction

Side-by-Side Comparison

Token Efficiency

Example Data:

{
  "users": [
    { "id": 1, "name": "Alice", "email": "alice@example.com", "role": "admin" },
    { "id": 2, "name": "Bob", "email": "bob@example.com", "role": "user" },
    { "id": 3, "name": "Charlie", "email": "charlie@example.com", "role": "user" }
  ]
}

JSON Tokens: ~85 tokens TOON Tokens: ~34 tokens Savings: 60% reduction

Readability

JSON: Excellent - widely understood, clear structure TOON: Good - uses indentation, similar to YAML, requires minimal learning

Compatibility

JSON: Universal support across all platforms and APIs TOON: Works with all LLMs (GPT-5, Claude, Gemini) that understand structured data

Use Cases

Use JSON when:

• You need universal compatibility
• Working with APIs that require JSON
• Data needs to be human-readable for non-technical users
• Token costs are not a concern

Use TOON when:

• Sending data to LLM APIs
• Token costs are significant
• Processing large datasets
• You want to optimize API performance

Performance Metrics

Real-World Scenarios

Scenario 1: E-commerce Product Catalog

JSON: 50,000 tokens → $1.50 per API call TOON: 20,000 tokens → $0.60 per API call Savings: $0.90 per call (60% reduction)

Scenario 2: User Management System

JSON: 10,000 tokens → $0.30 per API call TOON: 4,000 tokens → $0.12 per API call Savings: $0.18 per call (60% reduction)

Scenario 3: Configuration Data

JSON: 5,000 tokens → $0.15 per API call TOON: 2,000 tokens → $0.06 per API call Savings: $0.09 per call (60% reduction)

Migration Strategy

1. Start Small: Convert non-critical data first 2. Test Thoroughly: Ensure your LLM handles TOON correctly 3. Monitor Results: Track token usage and costs 4. Scale Gradually: Expand to more datasets as you gain confidence

Conclusion

While JSON remains the industry standard, TOON format offers significant advantages for LLM applications. The 60% token reduction can lead to substantial cost savings, especially for high-volume applications.

The best approach? Use JSON for general data interchange and TOON for LLM API interactions. Our free converter makes it easy to switch between formats as needed.

Try converting your JSON to TOON today and see the difference!