Formatter
JSON Formatter
Format, minify, validate, and clean up JSON data for easier reading or compact storage.
About JSON formatting, validation, and common questions
What is JSON?
Overview
JSON stands for JavaScript Object Notation. It is a lightweight text format used to represent structured data with objects, arrays, strings, numbers, booleans, and null values.
JSON is widely used because it is readable, compact, and easy for applications to exchange. It is common in APIs, configuration files, logs, web apps, test data, and data export workflows.
Where it is used
- API requests and responses
- Application configuration files
- Web app state, test fixtures, and mock data
- Logs, exported data, and integration payloads
- Package metadata and tool configuration
- Debugging structured data from backend services
Key facts
- JSON objects use curly braces.
- JSON arrays use square brackets.
- Object keys must be strings wrapped in double quotes.
- String values must use double quotes.
- JSON supports strings, numbers, booleans, null, objects, and arrays.
- Valid JSON does not allow trailing commas.
- Formatting changes whitespace and indentation, not the data itself.
- Minifying removes unnecessary whitespace to make JSON more compact.
Examples
Formatted JSON
Formatting adds indentation and line breaks so the structure is easier to read.
{"name":"MevoLab","type":"tools","active":true}{
"name": "MevoLab",
"type": "tools",
"active": true
}Minified JSON
Minifying removes extra spaces and line breaks while keeping the same data.
{
"name": "MevoLab",
"active": true
}{"name":"MevoLab","active":true}Invalid trailing comma
Trailing commas are a common reason JSON fails validation.
{"name":"MevoLab",}Invalid JSON. Please check the input and try again.Invalid unquoted key
JSON object keys must be wrapped in double quotes.
{name:"MevoLab"}Invalid JSON. Please check the input and try again.Common mistakes
- Using single quotes instead of double quotes for strings or object keys.
- Leaving a trailing comma after the last property or array item.
- Forgetting a closing brace, bracket, or quote.
- Mixing JavaScript object syntax with strict JSON syntax.
- Assuming formatted JSON is different data when only whitespace has changed.
- Sorting keys when the original key order is important for human comparison.
Limitations
- JSON does not support comments in standard syntax.
- JSON does not have native date, undefined, function, or special number types.
- Formatting very large JSON documents can be harder to inspect visually even when the syntax is valid.
- Sorted object keys can make comparison easier, but they may change the original display order.
Technical details
Formatting vs minifying
Formatting makes JSON easier to read by adding indentation and line breaks.
Minifying does the opposite: it removes unnecessary whitespace to create a compact JSON string for transfer, storage, or embedding.
Validation
Validation checks whether the input follows JSON syntax rules.
Common validation errors include missing quotes, trailing commas, extra brackets, unescaped characters, and incomplete values.
Sorting object keys
Sorting object keys alphabetically can make large objects easier to scan and compare.
This is useful for debugging, reviewing API responses, or checking configuration differences.
Frequently asked questions
What is the difference between JSON and a JavaScript object?
JSON is a strict text data format. A JavaScript object is a runtime value in JavaScript. They look similar, but JSON has stricter syntax rules.
Why does JSON require double quotes?
Standard JSON requires object keys and string values to use double quotes. Single quotes are common in JavaScript code, but they are not valid JSON.
What does minify JSON mean?
Minifying JSON removes unnecessary spaces, tabs, and line breaks. The data stays the same, but the text becomes more compact.
Does formatting JSON change the data?
No. Formatting only changes whitespace and indentation. The actual JSON values and structure remain the same.
Why is my JSON invalid?
Common reasons include missing double quotes, trailing commas, unmatched braces or brackets, unescaped characters, and incomplete values.
Checking the exact error location can help identify which part of the JSON needs to be fixed.
Should I sort object keys?
Sorting keys can make JSON easier to compare and review, especially for large objects. Keep the original order if the display order is meaningful for your workflow.
Your input is processed locally in this browser and is not uploaded to MevoLab.
Input JSON
Formatted JSON
Guide
How to use the JSON Formatter
Use this tool to format messy JSON, minify structured data, validate JSON syntax, and make API responses or configuration files easier to inspect.
Format JSON for readability
Paste your JSON into the input field and choose format mode to add indentation, line breaks, and a clean structure that is easier to read.
Minify JSON for compact output
Switch to minify mode to remove unnecessary spaces and line breaks, producing a smaller JSON string for storage, transfer, or embedding.
Validate JSON syntax
The formatter helps identify invalid JSON, such as missing quotes, trailing commas, unmatched brackets, or incorrectly structured values.
Sort object keys
Enable key sorting to organize object properties alphabetically, which can make large JSON objects easier to compare, scan, and debug.