Free JSON Formatter & Validator
Format, beautify, and validate JSON online. Paste JSON to get it properly indented with syntax highlighting. Errors shown with line information. Copy result in one click.
How to Use
When to Format JSON
JSON (JavaScript Object Notation) is the most widely used data format for APIs and configuration files. When working with raw API responses, the JSON is often minified — removing all whitespace to reduce payload size. A formatter makes it human-readable for debugging, code review, and documentation.
Common use cases: debugging REST API responses, formatting config files (package.json, tsconfig.json), preparing JSON for documentation, validating data before inserting into a database, and checking webhook payloads during integration testing.
Worked Example
Frequently Asked Questions
How do I format JSON online?
Paste your JSON into the left input box. The tool automatically validates and formats it as you type. You can also click Format/Beautify to manually trigger formatting. The formatted JSON with syntax highlighting appears in the right output panel.
What does JSON validation mean?
JSON validation checks that your text follows the correct JSON syntax rules: proper double-quoted strings, correct use of commas and colons, properly closed brackets and braces, and no trailing commas. If the JSON is invalid, the status bar shows the specific error message from the parser.
What is the difference between pretty print and minify?
Pretty print (beautify) adds indentation and newlines to make JSON readable for humans. Minify removes all unnecessary whitespace to reduce file size. Use pretty print when reading, debugging, or sharing JSON. Use minify for production API responses where smaller payload size matters.
How do I fix a JSON error?
Common JSON errors include: missing commas between array items or object properties, using single quotes instead of double quotes, trailing commas after the last item, and unquoted property keys. The error message shows the position of the problem. Look for the issue near the line and column number mentioned.
What is valid JSON syntax?
Valid JSON requires: double-quoted strings for keys and string values, numbers without quotes, true/false/null literals for booleans and null, arrays in square brackets with comma-separated values, and objects in curly braces with key-value pairs. Property names must be double-quoted strings. Trailing commas after the last item are not allowed.