JSON Formatter Guide: How to Format, Validate & Fix JSON

Complete guide on how to format and validate JSON online. Learn about JSON syntax, common errors, best practices, and how to use our free JSON validator tool effectively.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format. It's easy for humans to read and write, and easy for machines to parse and generate. JSON is widely used for APIs, configuration files, and data storage.

JSON Syntax Rules

Objects

Objects are enclosed in curly braces { } and contain key-value pairs.

Arrays

Arrays are enclosed in square brackets [ ] and contain ordered lists.

Strings

Strings must be enclosed in double quotes " ". Single quotes are not valid.

No Trailing Commas

Unlike JavaScript, JSON does not allow trailing commas after the last element.

How to Use This Tool

  1. Paste your JSON in the input area on the left
  2. The formatted JSON will appear on the right
  3. Errors will be highlighted with explanations
  4. Use the copy button to copy the formatted output