How to Format JSON Online
Learn how to pretty-print and validate JSON in your browser. Tips for fixing common syntax errors and sharing readable payloads.
Why format JSON?
Minified JSON is efficient for machines, but hard for humans to read. Formatting (also called beautifying or pretty-printing) adds indentation and line breaks so nested objects and arrays become visible at a glance.
Developers format JSON when debugging APIs, reviewing config files, checking webhook payloads, or preparing examples for documentation and code reviews.
How to format JSON in your browser
You do not need a desktop app or IDE plugin for everyday formatting. Paste your JSON into a browser-based formatter, run beautify, then copy the indented result.
- Open the Toolshelf JSON Formatter & Minifier.
- Paste your JSON into the input panel, or drop a local .json file.
- Click Format to pretty-print and validate, or Minify for a compact one-liner.
- Copy or download the output, or inspect nested fields in tree view.
Fix common JSON syntax errors first
A formatter can only beautify valid JSON. If parsing fails, fix the syntax before trying again.
- Remove trailing commas after the last property or array item.
- Use double quotes for keys and string values — not single quotes.
- Quote every key (unquoted keys are JavaScript object syntax, not JSON).
- Strip // and /* */ comments; standard JSON does not allow them.
- Replace undefined, NaN, or Infinity with null or valid JSON types.
When to minify instead
Beautify for humans. Minify when file size or network payload size matters — for example, shipping static JSON assets. Keep a readable source of truth in version control and minify only at build or publish time when needed.