How to Convert JSON to TOON and Vice Versa: Reduce LLM Token Costs

When building AI applications with Large Language Models (LLMs), every token counts - literally. API costs are based on token consumption, and JSON's verbose syntax wastes both tokens and money. This guide explains TOON (Token-Oriented Object Notation), a format specifically designed to reduce LLM token usage by up to 60% while maintaining full compatibility with JSON data structures.

Understanding TOON and JSON

What is JSON?

JSON (JavaScript Object Notation) is the universal data interchange format. It's used everywhere: APIs, databases, configuration files, and communication between systems. JSON's strength lies in its simplicity and universal support across all programming languages.

Example JSON:

{
  "name": "John Doe",
  "age": 30,
  "skills": [
    "Python",
    "JavaScript",
    "DevOps"
  ],
  "address": {
    "street": "123 Main St",
    "city": "Springfield",
    "zip_code": 12345
  }
}

What is TOON?

TOON (Token-Oriented Object Notation) is a minimal data format specifically designed to reduce token consumption in LLM applications. It eliminates redundant syntax like braces, brackets, and excessive quotes while maintaining data structure through indentation. TOON is perfect for AI chatbots, RAG systems, and any application where LLM API costs matter.

Example TOON:

name: John Doe
age: 30
skills[3]: Python,JavaScript,DevOps
address:
  street: 123 Main St
  city: Springfield
  zip_code: 12345

Both formats represent the same data, but TOON uses significantly fewer tokens.

Why TOON Saves Money on LLM APIs

1. Token Efficiency

TOON eliminates unnecessary syntax that JSON requires. No braces around objects, minimal brackets, and fewer quotes. This directly translates to lower token counts.

TOON (efficient):

name: John Doe
age: 30
skills[3]: Python,JavaScript,DevOps

JSON (verbose):

{
  "name": "John Doe",
  "age": 30,
  "skills": [
    "Python",
    "JavaScript",
    "DevOps"
  ]
}

The TOON version uses 30-40% fewer tokens for the same data.

2. Better LLM Comprehension

Independent benchmarks show LLMs achieve 86.6% accuracy with TOON compared to 83.2% with JSON. The cleaner syntax makes it easier for models to parse and understand data structures.

3. Cost Reduction at Scale

Applications making thousands of LLM API calls daily can reduce monthly costs by 40-50% through TOON conversion. The savings compound quickly when processing large datasets or handling high-volume chatbot interactions.

4. Maintains Full Compatibility

TOON maps directly to JSON data structures. You can convert between formats losslessly, meaning you can use TOON for LLM interactions while keeping JSON for traditional APIs and databases.

Why Choose TOON for LLM Applications?

1. Reduce API Costs

Since LLM providers charge based on token consumption, reducing tokens by up to 60% translates directly to proportional cost savings. For high-volume applications, this can save thousands monthly.

2. Faster Processing

Fewer tokens mean faster API responses and lower latency. This improves user experience in real-time applications like chatbots.

3. Increased Context Window Efficiency

With limited context windows (even in the latest models), TOON lets you fit more data in the same space. This is crucial for RAG systems and applications that need to pass large datasets to LLMs.

4. Simple, Readable Format

TOON uses indentation-based structure similar to Python and YAML. It's human-readable and easy to debug, unlike JSON's nested braces.

Why Choose JSON?

1. Universal Compatibility

JSON is supported everywhere. Every programming language, every API, every system understands JSON. If you need maximum compatibility with traditional systems, JSON is the answer.

2. Industry Standard

JSON is the established standard for REST APIs, webhooks, and microservices. It's what databases expect, what APIs return, and what most systems communicate with.

3. Tooling and Libraries

JSON has mature parsers and validators in every language. The ecosystem is vast and battle-tested.

Real-World Examples

LLM Prompt with TOON

If you're building a chatbot that needs to process user data:

name: Sarah Johnson
role: Senior Developer
skills[3]: Python,React,AWS
projects[2]{name,status}:
  E-commerce Platform,active
  Analytics Dashboard,completed

Token Count: ~45 tokens

Same Data in JSON

{
  "name": "Sarah Johnson",
  "role": "Senior Developer",
  "skills": [
    "Python",
    "React",
    "AWS"
  ],
  "projects": [
    {
      "name": "E-commerce Platform",
      "status": "active"
    },
    {
      "name": "Analytics Dashboard",
      "status": "completed"
    }
  ]
}

Token Count: ~75 tokens

Savings: 40% token reduction with TOON

Converting Between TOON and JSON

Converting TOON to JSON

When you need to send TOON data to a traditional JSON API:

Input:

name: John Doe
age: 30

Output:

{
  "name": "John Doe",
  "age": 30
}

Converting JSON to TOON

When preparing data for LLM processing:

Input:

{
  "users": [
    {
      "name": "Alice",
      "role": "Admin"
    },
    {
      "name": "Bob",
      "role": "User"
    }
  ]
}

Output:

users[2]{name,role}:
  Alice,Admin
  Bob,User

The data remains identical, only the format changes. You can try it yourself using our TOON to JSON converter.

Common Use Cases

Use TOON When:

• Building AI chatbots and virtual assistants
• Implementing RAG (Retrieval-Augmented Generation) systems
• Processing large datasets with LLMs
• Optimizing prompt engineering workflows
• Reducing API costs for high-volume applications
• Working with context window limitations
• Passing structured data to ChatGPT, Claude, or Gemini

Use JSON When:

• Building REST APIs
• Exchanging data with traditional systems
• Storing records in databases
• Creating webhooks and integrations
• Working with legacy systems that require JSON
• Using JavaScript/TypeScript natively

TOON to JSON Converter Tool

If you frequently convert between TOON and JSON during AI development, a dedicated converter tool can save significant time. These tools typically offer:

• Real-time conversion - See results as you type
• Token count comparison - See exactly how many tokens you save
• Error detection - Instant feedback on syntax errors
• Bidirectional conversion - Convert both directions seamlessly
• Copy to clipboard - One-click copying of results

Rather than manually formatting data or writing scripts for conversions, an online converter is fast, free, and requires no setup. Try the JSON to TOON converter to see your token savings.

When to Convert Between Formats

You might need to convert between TOON and JSON in these scenarios:

1. LLM Integration

Your application stores data in JSON (database, API responses) but needs to pass it to an LLM. Convert to TOON before sending to reduce costs.

2. Hybrid Architectures

Use JSON for traditional APIs and databases, convert to TOON only for LLM processing. This gives you the best of both worlds.

3. Data Export from LLMs

LLMs might output TOON format. Convert to JSON for storage or API integration with other services.

4. Prompt Engineering

When crafting prompts with structured data, convert JSON examples to TOON to fit more context in the limited window.

Token Savings Calculator

Here's how token savings scale:

| JSON Tokens | TOON Tokens | Savings | Use Case                |
| ----------- | ----------- | ------- | ----------------------- |
| 1,000       | 600         | 40%     | Small chatbot response  |
| 10,000      | 6,000       | 40%     | Medium dataset          |
| 100,000     | 60,000      | 40%     | Large RAG system        |
| 1,000,000   | 600,000     | 40%     | High-volume application |

With proportional cost reduction, the savings compound at scale.

Best Practices

For LLM Applications

• Convert JSON to TOON before sending to LLMs
• Keep data in JSON for traditional storage and APIs
• Use TOON for all prompt engineering with structured data
• Monitor token counts to verify savings
• Test LLM accuracy with both formats (TOON often improves comprehension)

For Hybrid Systems

• Store data in JSON (databases, traditional APIs)
• Convert to TOON at the LLM integration boundary
• Convert back to JSON for responses if needed
• Use conversion tools to automate the process

Conclusion

TOON and JSON aren't competing formats - they serve different purposes. Use JSON for traditional APIs, databases, and system integration where universal compatibility is critical. Use TOON for LLM applications where token efficiency directly impacts costs and performance.

For AI applications processing significant data volumes, converting JSON to TOON can reduce API costs by 40-50% while potentially improving model comprehension. The format is simple to implement, fully compatible with JSON data structures, and supported by all major LLMs.

If you're building with ChatGPT, Claude, Gemini, or any other LLM, start converting your JSON data to TOON. The token savings will add up quickly, and your applications will be more cost-effective at scale.

Try our free tools:

• JSON to TOON converter
• TOON to JSON converter

Start using TOON for your next LLM project - your API budget will thank you.