JSONToTable

How to Convert JSON to TOON (Step-by-Step)

Learn the easy way to convert JSON to TOON and save 50% on tokens

Published: January 2025 • 8 min read

Converting JSON toTOON format can reduce your LLM token usage by up to 50%. The conversion process follows a few straightforward rules.

This guide shows you how to convert JSON to TOON with step-by-step examples. You can convert files manually or use ourJSON to TOON converter tool.

What You'll Learn

  • •Core conversion rules for standard use cases
  • •Array conversion techniques for maximum token savings
  • •Handling nested objects and special cases
  • •Verification steps to ensure correct conversion

Core Conversion Rules

TOON conversion follows three basic rules:

1

No Quotes on Keys

JSON:

"name": "John"

TOON:

name: "John"

Remove quotes from property names.

2

List Fields Once

Instead of repeating:

{id: 1, name: "A"}
{id: 2, name: "B"}

Define once:

{id,name}

This provides the majority of token savings.

3

Use Indentation

JSON:

{user: {...}}

TOON:

user:
  ...

Use 2 spaces for each nesting level.

These three rules cover most conversion scenarios. The following examples demonstrate how to apply them.

Step 1: Simple Objects

Start with a basic JSON object to understand the fundamental transformation:

BEFORE (JSON)
{
  "name": "Sarah Mitchell",
  "age": 32,
  "email": "[email protected]",
  "active": true,
  "role": "Senior Developer"
}
AFTER (TOON)
name: "Sarah Mitchell"
age: 32
email: "[email protected]"
active: true
role: "Senior Developer"

Changes Applied

  • 1.Removed outer curly braces - TOON doesn't need them for the root object
  • 2.Removed quotes from keys - "name" → name
  • 3.Kept quotes on string values - "Sarah Mitchell" stays quoted
  • 4.Removed commas at the end of lines - TOON uses line breaks instead

Result: Cleaner syntax with reduced token count.

Step 2: Nested Objects

For nested objects, TOON uses indentation instead of curly braces, similar to Python or YAML:

BEFORE (JSON)
{
  "user": {
    "name": "Maeve Winters",
    "email": "[email protected]"
  },
  "address": {
    "street": "123 Main St",
    "city": "Boston",
    "zipCode": "02101"
  }
}
AFTER (TOON)
user:
  name: "Maeve Winters"
  email: "[email protected]"
address:
  street: "123 Main St"
  city: "Boston"
  zipCode: "02101"

Indentation Rules

  • •Parent key + colon → then hit Enter
  • •Indent children by 2 spaces (not tabs)
  • •Each level deeper adds 2 more spaces
  • •No closing braces needed - indentation defines structure

Step 3: Arrays of Simple Values

Arrays of strings, numbers, or booleans use a length marker notation:

BEFORE (JSON)
{
  "tags": ["javascript", "react", "typescript"],
  "scores": [95, 87, 92, 88],
  "features": ["fast", "secure", "scalable"]
}
AFTER (TOON)
tags[3]: "javascript", "react", "typescript"
scores[4]: 95, 87, 92, 88
features[3]: "fast", "secure", "scalable"

Array Syntax

arrayName[count]: value1, value2, value3
  • 1.Name + Length: tags[3] means "tags array with 3 items"
  • 2.Colon + Space: Separate the declaration from values
  • 3.List values: Comma-separated on a single line
  • Note:Count must match - If you say [3], there must be exactly 3 items

Step 4: Arrays of Objects

Primary Token Savings

Converting arrays of objects provides the largest token reduction. This technique can reduce token usage by approximately 50%.

Instead of repeating property names for every object, TOON lets you define them once at the top:

BEFORE (JSON - 95 tokens)
{
  "customers": [
    {
      "id": 1,
      "name": "Sarah Mitchell",
      "email": "[email protected]",
      "active": true
    },
    {
      "id": 2,
      "name": "Michael Chen",
      "email": "[email protected]",
      "active": true
    },
    {
      "id": 3,
      "name": "Jennifer Kumar",
      "email": "[email protected]",
      "active": false
    }
  ]
}
AFTER (TOON - 48 tokens)
customers[3]{id,name,email,active}:
  1,Sarah Mitchell,[email protected],true
  2,Michael Chen,[email protected],true
  3,Jennifer Kumar,[email protected],false

Saved 47 tokens = 50% reduction

Applied across thousands of records, this adds up to significant cost savings.

Step-by-Step Conversion Process

  1. 1
    Identify common properties: All objects have the same keys:id, name, email, active
  2. 2
    Count the objects: There are 3 customers
  3. 3
    Write the header:customers[3]{id,name,email,active}:
    • • [3] = number of objects
    • • {id,name,email,active} = field names (defined once)
  4. 4
    Create data rows: Each object becomes one line with values in the same order as fields
    1,Sarah Mitchell,[email protected],true
  5. 5
    Indent each row: Add 2 spaces before each data row for readability

Step 5: Converting Complex Nested Structures

Real-world data often combines objects, nested objects, and arrays:

Original JSON

{
  "company": "Tech Solutions Inc",
  "employees": [
    {
      "id": 101,
      "name": "Sarah Mitchell",
      "role": "Engineer",
      "salary": 95000
    },
    {
      "id": 102,
      "name": "Michael Chen",
      "role": "Designer",
      "salary": 85000
    }
  ],
  "metadata": {
    "created": "2025-01-15",
    "version": 2
  }
}

Converted TOON

company: "Tech Solutions Inc"
employees[2]{id,name,role,salary}:
  101,Sarah Mitchell,Engineer,95000
  102,Michael Chen,Designer,85000
metadata:
  created: "2025-01-15"
  version: 2

Strategy for Complex Conversions:

  • •Process top-level properties first
  • •Convert arrays of objects to structured arrays (maximum efficiency)
  • •Use indentation for nested objects
  • •Maintain consistent indentation (2 spaces per level)

Handling Special Cases

Case 1: Data Contains Commas

When values contain commas, use pipe delimiter instead:

# JSON with comma-containing values
# addresses: [{"street": "123 Main St, Suite 100", "city": "Boston"}]

# TOON with pipe delimiter
addresses[1]{street,city}|:
  123 Main St Suite 100|Boston

Case 2: Null Values

JSON null becomes TOON null:

# JSON: {"name": "John", "middleName": null, "age": 30}
# TOON:
name: "John"
middleName: null
age: 30

Case 3: Empty Arrays

Empty arrays are explicitly marked:

# JSON: {"tags": [], "count": 0}
# TOON:
tags[0]:
count: 0

Case 4: Mixed Array Types

If array objects have different properties, use nested object notation:

# When objects have inconsistent properties
items[2]:
  - id: 1
    type: "product"
    price: 99.99
  - id: 2
    type: "service"
    duration: "1 hour"

Optimization Tips

Prioritize Arrays of Objects

These benefit most from TOON conversion. Focus your conversion efforts on arrays of objects with consistent properties - they'll show the biggest token reduction.

Use Our Converter Tool

For large JSON files, use our JSON to TOON converter which automatically handles all conversion rules and optimization.

Validate After Conversion

Always run converted TOON through our TOON Validator to catch syntax errors, length mismatches, or formatting issues.

Add Comments for Context

TOON supports comments. Add them to explain data structure or provide context for LLMs:

# Customer churn analysis data - Q4 2024
customers[3]{id,name,churn_risk}:
  1,Sarah Mitchell,0.15
  2,Michael Chen,0.82

Common Mistakes to Avoid

  • •Array count mismatch - if you write [3], make sure there are exactly 3 items
  • •Inconsistent indentation - use 2 spaces, not tabs or 4 spaces
  • •Missing quotes on strings - numbers don't need quotes, but text does
  • •Wrong boolean format - use lowercase true and false
  • •Field order mismatch in arrays - values must match the order in {field1,field2}

Use the TOON Validator to catch these errors automatically.

Quick Reference

Simple Object

name: "value"
age: 25

Nested Object

user:
  name: "value"
  age: 25

Simple Array

tags[3]: "a", "b", "c"

Array of Objects

users[2]{id,name}:
  1,Alice
  2,Bob

Conversion Tools

Use these tools for automated conversion and validation:

JSON to TOON

Automatic conversion with token count

TOON Validator

Check if your conversion is correct

TOON to JSON

Convert back to verify accuracy

TOON Formatter

Make your TOON pretty

JSON Formatter

Format source JSON first

TOON Viewer

Visualize your converted data

Additional Resources

Learn more about TOON and JSON with these resources:

TOON Documentation

Advanced Topics

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