JSON Formatter
JSON Formatter & Validator
Paste JSON to pretty-print, minify, or validate it. Errors show the exact line and column. Everything runs locally in your browser.
Status: Waiting for input…
How to use it
- Paste or type JSON into the input.
- Pick Pretty (indent) or Minify, then choose indent size.
- Copy or download the result, or read the error message if the JSON is invalid.
Examples
Pretty-print API response
{"id":1,"name":"Ada"} → { "id": 1, "name": "Ada" }Minify for a fetch body
{ "x": 1 } → {"x":1}Spot a trailing comma
Pasting
{"a":1,} shows the exact position of the invalid comma.About this tool
A no-frills JSON formatter. Uses your browser's native JSON.parse, so behaviour matches what your JavaScript code will see. Handy for debugging API responses, cleaning config files, or checking that a webhook payload is valid before shipping it.
FAQ
- Is my JSON sent to a server?
- No. Parsing and formatting run entirely in your browser. Nothing is uploaded or logged.
- What indent should I pick?
- 2 spaces is the most common in web code. Use 4 for Python-style output, or Tab if your team formats with tabs.
- Why does it say 'Unexpected token'?
- That means the JSON is invalid at the position shown. Common causes are trailing commas, single quotes instead of double, or unquoted keys.
- Can it fix invalid JSON automatically?
- It won't guess your intent, but the error message tells you the exact line and column, so fixing it usually takes seconds.
- Is there a size limit?
- The tool safely handles files up to about 5 MB. Larger inputs are refused so the page stays responsive.
Privacy
Everything runs locally in your browser. Your input is never uploaded, logged, or stored.