Is the JSON I enter sent to a server?

No. It's processed entirely in your browser using JSON.parse/JSON.stringify.

Why do I see a "syntax error" message?

If the text doesn't follow standard JSON syntax (single quotes aren't allowed, trailing commas aren't allowed, etc.), you'll be shown the error location.

What's the difference between Pretty and Minify?

Pretty adds indentation to make the JSON easy for humans to read, while Minify removes unnecessary whitespace and line breaks to reduce file size.

📘 JSON Formatter

Pretty-print or minify JSON, and validate its syntax.

JSON Input

Result

How to use

Paste your JSON text into the input box on the left.
Click "Pretty" or "Minify" to convert it.
Any syntax errors are shown immediately with their location.

🎯 Use Cases

Debugging API responses — turn a JSON response squashed onto one line into something readable so you can find the field you need
Cleaning up config files — reformat files like package.json or tsconfig.json for readability
Optimizing transfer size — remove unnecessary whitespace and line breaks with Minify to shrink API response size
Validating hand-written JSON — catch quote or comma mistakes instantly when typing config values or test fixtures by hand

Example

Input

{"name":"developk","tags":["json","tool"],"active":true}

Output

{
  "name": "developk",
  "tags": [
    "json",
    "tool"
  ],
  "active": true
}

This is the result of applying "Pretty" to JSON squashed onto a single line. A 2-space indent is added so keys, values, and array items each sit on their own line.

Common JSON syntax errors

Invalid	Why it fails	Valid
`{'name':'a'}`	Single quotes aren't valid JSON syntax	`{"name":"a"}`
`{"a":1,}`	Trailing comma after the last item	`{"a":1}`
`{a:1}`	Key written without quotes	`{"a":1}`
`{"a":undefined}`	`undefined` isn't a valid JSON value	`{"a":null}`
`{"a":01}`	Leading zero before a number	`{"a":1}`

JSON looks similar to a JavaScript object literal but is a stricter subset. Pasting code straight from JavaScript often triggers a syntax error for one of the reasons above.

FAQ

Is the JSON I enter sent to a server?: No. It's processed entirely in your browser using JSON.parse/JSON.stringify.
Why do I see a "syntax error" message?: If the text doesn't follow standard JSON syntax (single quotes aren't allowed, trailing commas aren't allowed, etc.), you'll be shown the error location. See the comparison table above for common patterns.
What's the difference between Pretty and Minify?: Pretty adds indentation to make the JSON easy for humans to read, while Minify removes unnecessary whitespace and line breaks to reduce file size. Most API responses sent over the wire are minified.
Does this handle JSON with comments?: No. Standard JSON doesn't support comments. Remove any // or /* */ comments before pasting your text in.