Free Online JSON Formatter & Validator

How to use the JSON formatter

1. Paste your JSON into the input box above.
2. Press Format to beautify it with 2-space indentation, or Minify to strip all whitespace and shrink it to one line.
3. If the JSON is invalid, the tool shows an error message - fix the problem and press Format again.
4. Press Copy to copy the clean JSON to your clipboard.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight text format for storing and moving data. It is built from simple structures you already know: objects with name/value pairs, arrays of values, strings, numbers, booleans and null. Nearly every modern API returns JSON, and config files, package manifests and database exports use it too.

JSON looks simple, but it is strict. A single trailing comma or a pair of single quotes makes the whole document unreadable to a parser - which is exactly why a formatter with built-in validation saves so much debugging time.

JSON formatter example

Here is the same JSON before and after formatting. The data is identical - only the presentation changes:

Before

{"name":"Ava","age":29,"skills":["HTML","CSS","JS"],"active":true}

After pressing Format

{
  "name": "Ava",
  "age": 29,
  "skills": [
    "HTML",
    "CSS",
    "JS"
  ],
  "active": true
}

Formatted JSON is much easier to scan for typos, missing keys and wrong values before you send it to an API or save it as a config file. Minified JSON, on the other hand, is best for sending over a network, because it removes every unnecessary byte without changing the data.

Common JSON errors

Most invalid JSON fails for one of these reasons. Each is easy to spot once you know what to look for - and this tool's error message will point you at the exact spot:

JSON validator

A JSON validator checks your text against the official JSON specification and tells you whether a parser can read it. When you press Format or Minify on this page, the tool runs your input through the browser's built-in JSON parser. If parsing succeeds, you see "Valid JSON" and get the formatted result. If it fails, you get the exact parser error - for example "Unexpected token } in JSON at position 42" - which points you straight to the problem.

Validation matters because a single misplaced comma can break an API request, crash an app on load or silently drop data. A good workflow is: paste the response from an API, validate and format it, inspect the structure to confirm the fields you expect, fix any issues, then copy the clean result into your code or config file.

Unlike server-side validators, everything here runs in your browser. Your JSON is never uploaded, so it is safe to validate API keys, tokens and other sensitive data - although you should still avoid pasting real production secrets anywhere you can avoid it.

Why format and validate JSON

Raw JSON from an API is often one long line that is hard to read. Formatting makes the structure clear, which helps when you debug a request, check a config file or share data with a teammate.

Minifying does the opposite and is useful before you send JSON over a network or paste it into code.

Frequently asked questions

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