JSON Formatter & Validator

What Is JSON and Why Format It?

JSON (JavaScript Object Notation) is the universal language of APIs — almost every web service, mobile app, and database communicates using JSON. When you receive raw API responses, they're often a single unformatted line of text that's nearly impossible to read.

A JSON formatter (also called JSON prettifier or JSON beautifier) adds proper indentation and line breaks to make the structure readable. It also validates the JSON — flagging syntax errors like missing commas, unclosed brackets, or unquoted keys.

Common JSON Errors and How to Fix Them

• Missing comma: Every key-value pair in an object must be separated by a comma, except the last one. {"a":1 "b":2} → fix: add comma after 1
• Trailing comma: JSON does not allow trailing commas. {"a":1,} is invalid — remove the last comma
• Unquoted keys: JSON keys must always be in double quotes. {name: "value"} → fix: {"name": "value"}
• Single quotes: JSON requires double quotes, not single quotes
• Undefined or NaN values: These are JavaScript values, not valid JSON. Replace with null or a number

Frequently Asked Questions

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