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JSON Formatter & Validator

Clean, format, and validate your JSON data instantly. A simple and powerful JSON viewer and editor for developers.

Raw Input
Tree View (Editable)

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, language-independent data interchange format. It is easy for humans to read and write, and easy for machines to parse and generate.

Did you know? JSON is the world's most popular data format, effectively replacing XML in most modern Web APIs.

JSON Syntax Rules

Valid Syntax

  • •Data is in name/value pairs.
  • •Keys MUST be enclosed in double quotes.
  • •Strings must use double quotes.
  • •Data is separated by commas.

Common Errors

  • ×Trailing comma after the last element.
  • ×Using single quotes instead of double quotes.
  • ×Missing closing braces or brackets.
  • ×Adding comments.

Common Use Cases

Web APIs (REST/GraphQL)

Standard format for API data exchange.

Configuration Files

Settings storage (package.json, etc.).

NoSQL Databases

Data storage in MongoDB, CouchDB.

How to use the JSON Editor

  1. 1

    Paste JSON into the Raw Input panel, for example a response copied from the browser network tab, a config file or a log line.

  2. 2

    Press Beautify to indent it, or Minify to remove all whitespace. If the text is not valid JSON, the tool shows an error so you can find the broken comma or quote.

  3. 3

    Use the Tree View to explore nested objects and arrays. You can expand, collapse and edit values directly, which is faster than scrolling through thousands of lines.

  4. 4

    Copy the result back into your code, API client or configuration file with Copy Results.

Practical examples

Reading API responses

A minified response of 20 KB on one line is impossible to read. Beautify turns it into an indented structure where you can find the field you need in seconds.

Fixing config files

package.json, tsconfig.json or a VS Code settings file refuse to load because of one trailing comma. The validator points out the problem before your build fails.

Shrinking payloads

Minify a JSON fixture or a request body before pasting it into a curl command, an environment variable or a test, where line breaks would cause trouble.

Editing nested data

Change a value deep inside a feature flag or a mock response in the tree editor instead of counting brackets by hand.

Frequently asked questions

Why is my JSON invalid?+

The most common causes are trailing commas, single quotes instead of double quotes, comments, and unquoted keys. These are allowed in JavaScript objects but not in strict JSON (RFC 8259).

What is the difference between beautify and minify?+

Both keep exactly the same data. Beautify adds indentation and line breaks for people to read, minify removes them so the file is as small as possible for transfer or storage.

Is there a size limit?+

There is no fixed limit because everything runs in your browser. Files of several megabytes work, though very large documents depend on the memory of your device.

Is my JSON uploaded anywhere?+

No. Parsing, formatting and editing happen locally in the browser, so API keys or customer data inside the JSON never leave your computer.