JSON Prettifier
Beautify or minify JSON, with support for relaxed JSON5 syntax such as comments, trailing commas, single-quoted strings, and unquoted keys. Output is always standard JSON.
FreeOnline Tool
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Customer Service
Click to view QQ number
877716587
How to Use
- Paste your JSON into the input box. Relaxed JSON5 input with comments, trailing commas, or single-quoted strings is also accepted.
- Formatting runs automatically as you type, and you can also trigger it manually with the Format or Minify button.
- The formatted or minified result appears in the output box below.
- Click Copy result to put the output on your clipboard.
- Click Load sample data to see an example that includes JSON5 syntax such as comments and trailing commas.
- Click Clear to empty both the input and the output.
Features
- Turns minified or messy JSON into a readable form with 2-space indentation in one click.
- Collapses formatted JSON back into a single line in one click.
- Beyond standard JSON, it accepts relaxed JSON5 syntax: line comments //, block comments /* */, trailing commas, single-quoted strings, and unquoted keys. Such input formats and minifies normally, and the output is always standard JSON.
- Processes input as you type, so pasting is enough to see the result without clicking anything.
- Syntax errors are reported with a specific message right below the input box.
Use Cases
Debugging API responses
Format a minified API response so you can read the data structure and debug faster.
Code review
Format inline minified JSON during review so the reviewer can read it and spot potential issues.
Log analysis
Format JSON fragments buried in logs so you can inspect the details of a problem record by eye.
Writing documentation
Insert neatly formatted JSON examples into technical or API documentation to make it more readable and professional.
FAQ
Does formatting change the data?
No. Formatting only adds indentation and line breaks, and minifying only removes extra whitespace. Keys, values, and structure stay exactly the same, so the meaning is identical to the original.
Is JSON5 syntax supported?
Yes. The tool parses the input as standard JSON first and falls back to JSON5 if that fails, so line comments //, block comments /* */, trailing commas, single-quoted strings, and unquoted keys all work. The formatted or minified output is always converted to standard JSON.
Can I use the formatted output in production?
Yes, the formatted JSON is perfectly valid. Production systems usually prefer minified JSON to cut transfer size, while the formatted version is better for reading during development.
What should I do when my input reports an error?
The tool shows the specific message below the input box. Check for unbalanced brackets or quotes and for missing or extra commas, and formatting reruns automatically once you fix it. Comments, trailing commas, and single quotes are not errors, since JSON5 input is supported.