JSON Formatter & Validator
Format runs JSON.stringify with a 2-space indent. Minify runs JSON.stringify with no indent. Validate only parses. Invalid input does not rewrite the output box.
Runs in your browser. Nothing you enter is uploaded.
Worked examples
Input {"hello":"world","list":[1,2,3]}
| Format | { "hello": "world", "list": [ 1, 2, 3 ] } |
|---|---|
| Minify | {"hello":"world","list":[1,2,3]} |
| Validate | Status "Valid JSON" and the output box is left as it was |
Input {hello:1}
| Format, Minify, or Validate | Status starts with "Invalid JSON: " and the output box is not replaced |
|---|
The rest of the message is the browser's own JSON.parse error. Keys must be in double quotes.
Buttons
| Button | What it writes |
|---|---|
| Format | JSON.stringify(value, null, 2) |
| Minify | JSON.stringify(value) |
| Validate | No new text. Status only. |
| Copy | The output box, or the input if the output is empty |
Paste any JSON and this tool instantly formats it with clean indentation, or flags exactly where it breaks. A JSON formatter turns a dense, single-line blob into a readable, indented structure so you can scan nested objects and arrays at a glance. Essential when debugging API responses or config files. It also works as a validator: if your JSON has a stray comma, unquoted key or missing bracket, you get a clear error instead of a silent failure. Everything runs locally in your browser, so even sensitive payloads never touch a server. Use the buttons to beautify with 2-space indent, minify to a compact single line, or validate without changing anything.
How to use JSON Formatter & Validator
- Paste your JSON into the input box.
- Click Beautify to indent it or Minify to compress it.
- Read any validation error if the JSON is malformed.
- Copy the formatted output.
Frequently asked questions
How many spaces is the indent?
Two. That is the third argument to JSON.stringify.
What does {"hello":"world","list":[1,2,3]} format to?
A pretty-printed object with "hello" and a "list" array of 1, 2 and 3, each on its own indented line.
Does a trailing comma pass?
No. JSON.parse rejects it, and this page reports Invalid JSON.
Is the JSON uploaded?
No. Parsing and formatting run in the browser.
Is JSON Formatter & Validator any good?
Give your verdict. Sign-in needed to vote and comment.
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