Format valid JSON
Input
{"name":"Alice","age":28,"tags":["api","debug"]}
Output
Pretty-print: readable, indented JSON Minify: compact one-line JSON
JSON formatter and minifier
Format or minify JSON and locate syntax errors by line and column.
Paste JSON, run an action, and copy the result in one short flow. Processing stays in your browser.
Input data never leaves your browser (browser-only processing).
Suitable for confidential data.
How to use
- Paste JSON into the input pane.
- Choose Pretty-print or Minify.
- Copy or download the result.
Shortcuts
Ctrl/Cmd + Enter: Pretty-print
Ctrl/Cmd + Shift + Enter: Minify
Ctrl/Cmd + L: Clear (with confirmation)
Sample
Find an invalid JSON error
Input
{"name":"Alice","age":28,}
Output
The error banner shows the line, column, and nearby snippet
What is JSON pretty-printing?
Pretty-printing adds indentation and line breaks so JSON is easier to read, debug, and review.
What does JSON minify do?
Minifying removes whitespace and line breaks to reduce the payload and keep JSON compact.
Common errors and how to fix them
- Trailing comma after the final item (for example: {"a":1,})
- Keys or string values are missing double quotes
- Comment syntax appears (standard JSON does not allow // or /* */)
FAQ
I get an error
The tool reports the line, column, and nearby text. Select Jump to Error to place the cursor at the exact location.
Can I use commented JSON (JSONC/JSON5)?
Standard JSON has no comments. Turn on “Strip comments before parse” only when needed; compatibility is not complete.
Large JSON feels slow
Parsing and stringifying happen in your browser. Size limits keep the editor responsive for large inputs.
Is data uploaded?
No. Parsing, formatting, and minifying all happen locally in your browser.
I see \uXXXX output
Disable Unicode Escape to output readable characters instead of \uXXXX sequences.