Format, Validate, and Minify JSON

JSON resembles JavaScript syntax but is more restrictive. This is valid JavaScript but invalid JSON:

{
  name: 'Mina',
  active: true,
  joined: new Date(),
}

The property name is not quoted, the string uses single quotes, new Date() is a JavaScript expression, and the final property has a trailing comma. Valid JSON would be:

{
  "name": "Mina",
  "active": true,
  "joined": "2026-08-19T00:00:00.000Z"
}

JSON carries data, not executable code or language-specific object instances.

Minification still requires parsing, so invalid input cannot be minified. Select Minify, and the tool parses the input and serializes it without indentation. Formatted input:

{
  "name": "Mina",
  "roles": [
    "editor",
    "reviewer"
  ]
}

Minified output:

{"name":"Mina","roles":["editor","reviewer"]}

Minification reduces plain-text size by removing indentation and line breaks. Network compression such as gzip or Brotli already compresses repeated whitespace efficiently, so the transmitted-size benefit may be smaller than the raw character difference suggests. Keep a readable source version for maintenance and generate compact output during a build or delivery step when possible.

1. 1. Trim leading and trailing whitespace from the input.
2. 2. Parse the complete string with JSON.parse().
3. 3. For formatted output, call JSON.stringify() with the selected number of spaces (2, 3, 4, or 8).
4. 4. For minified output, call JSON.stringify() without indentation.
5. 5. Display a success message and transformed output.
6. 6. If parsing throws an error, clear the output and show the parser message.

The tool does not use eval() and does not execute pasted JSON as code.

JSON syntax does not give duplicate property names a reliably portable meaning. When {"status":"draft","status":"published"} is parsed into a JavaScript object, the later value normally replaces the earlier one, so formatting or minifying can produce {"status":"published"}.

Different tools and languages may reject duplicates, keep the first value, keep the last value, or expose all occurrences. Resolve duplicate keys before relying on the document. This formatter is not a duplicate-key linter, because it parses into a standard JavaScript value before serializing.

Formatting and minification remove or add whitespace between JSON tokens. They do not intentionally remove spaces that belong to a quoted string value. These values are different: {"message":"hello world"} and {"message":"helloworld"}.

Minification preserves the space in "hello world" because it is data rather than formatting. Escape sequences may be serialized consistently by the browser, so the textual representation can change while the parsed string value remains equivalent.

This JSON is syntactically valid, yet an application may reject it because email should be a string, quantity must be positive, or currency must use an approved code:

{
  "email": 42,
  "quantity": -1000,
  "currency": "UNKNOWN"
}

Syntax validation answers "can this text be parsed as JSON?" Schema or business validation answers "does this parsed value have the fields, types, formats, ranges, and relationships this application requires?" Use JSON Schema, API documentation, typed validation, or application-specific checks for the second question.

JSON frequently contains API keys, authentication tokens, session identifiers, passwords, personal information, customer records, private URLs, and internal infrastructure details. Remove or replace sensitive values before using them in examples, issue reports, screenshots, logs, chat, or public code.

The formatter does not execute JSON, but a valid JSON document can still contain dangerous or sensitive data that becomes harmful when passed into another application. Do not assume that formatting untrusted JSON makes it safe for HTML rendering, database queries, shell commands, template engines, object merging, or authorization logic.

JSON content is parsed and serialized in browser memory and is not sent to WeConvertFiles for formatting. The tool uses native browser JSON functions and does not require a remote formatting API.

If a visitor consents to site analytics, separate usage information such as visits, clicks, device details, or formatting events may be collected. Those analytics do not receive the pasted JSON content.

The local environment still matters. Browser extensions, malware, clipboard managers, screen recording, shared devices, and copied examples can expose sensitive values independently of the formatter.