JSON Formatter and Validator

Paste your JSON into the input box, or drop a .json file onto it, then press Format (or Ctrl+Enter). The result appears below with your chosen indentation: two spaces, four spaces or a tab. Minify removes every unnecessary space, which is what you want before sending a payload over the wire, and Validate only checks the syntax.

The parser follows the JSON standard strictly, so it rejects things JavaScript itself tolerates: trailing commas, single quotes, unquoted keys, comments and leading zeros. When something is wrong the message names the problem and the position, for example Line 3, column 8, and a Jump to error button selects the offending character. For common near-JSON mistakes, Try to fix common mistakes strips comments, converts single quotes and removes trailing commas.

Switch the output to Tree to collapse and expand objects and arrays, which is the fastest way to explore a large API response. Tick Sort keys to order object keys alphabetically, which makes two documents easier to compare.

Input, copied straight from a log line:

{"user":{"id":7,"name":"Ann","roles":["admin","dev"]},"active":true}

Formatted with two spaces:

{
  "user": {
    "id": 7,
    "name": "Ann",
    "roles": [
      "admin",
      "dev"
    ]
  },
  "active": true
}

Now remove the closing quote after Ann. The tool now reports an error such as Expected "," or "}" but found "r" together with the line and column where parsing stopped, so you can go straight to the typo instead of scanning the whole document.

• Large files: inputs over 400 KB are formatted in a background worker so the page does not freeze. The tree view is skipped for those.
• Big numbers: JSON numbers are read as JavaScript numbers, so integers beyond 9,007,199,254,740,991 lose precision. Keep such IDs as strings.
• Duplicate keys: JSON allows them but most parsers keep only the last one. Sorting and formatting here keep the last value too.
• Sharing: the share button puts small inputs in the link. Do not use it for secrets.