JSON Formatter Guide: How Pretty-Printing Works
Learn how JSON formatting turns compact data into readable, indented structure without changing its meaning.
What is the JSON Formatter & Validator?
Paste JSON and this tool checks whether it parses, then prints it neatly indented so its structure is easy to read. If the input is not valid JSON, it shows the parser error message instead of guessing a fix, so you can find the faulty spot. It handles nested objects, arrays, numbers, strings, booleans and null values.
How to use it
- Paste your JSON into the box.
- Choose 2-space or 4-space indentation.
- Click Format JSON and read the formatted result or the error message.
Worked example
For the sample, the tool prints the object with 4-space indentation, one key per line, with the tags array on its own indented lines.
Why does formatted JSON still fail in another tool?
Usually because a value itself is the problem, such as a trailing comma or an unquoted key. Formatting only rearranges whitespace, so it cannot repair invalid syntax.
Frequently asked questions
What happens if my JSON is invalid?
The tool shows the parser error message, such as an unexpected token, so you can locate and fix the problem.
Does it change my values?
No. Formatting only changes whitespace and line breaks; keys, values and their order are kept as parsed.