How to format and validate JSON
Paste JSON text into the input, choose Format JSON, and select 2 or 4 spaces of indentation. The tool uses the browser's built-in JSON parser and displays an easy-to-read representation of valid JSON. Choose Minify JSON to remove unnecessary spaces, or Validate only to check the structure without producing converted text.
JSON formatting example
{"name":"Ada","active":true,"items":[1,2]}Formatting adds line breaks and indentation around the keys and array without changing the underlying JSON values. Validation checks syntax such as double-quoted property names, correctly paired brackets and commas.
Common JSON errors
Strict JSON does not support comments, single-quoted property names or trailing commas. For example, {'name':'Ada'} is not valid JSON. Use {"name":"Ada"} instead. JSON supports numbers, strings, booleans, arrays, objects and null.
Privacy and limits
Everything runs on your device. Toolenox does not receive pasted JSON or conversion output, and no sign-up is needed. This utility handles up to 1 MiB of input text and 2 MiB of output text; exceptionally deep documents may not be formatable. Avoid confidential data on shared devices. Like standard JavaScript JSON parsing, very large numeric identifiers outside the safe integer range may lose precision; store those identifiers as JSON strings. Duplicate object keys may be collapsed during parsing.
Frequently asked questions
What is the difference between JSON formatting and CSV conversion?
Formatting rearranges the presentation of existing JSON. The separate CSV to JSON converter transforms tabular data into objects and vice versa; it serves a different purpose.
Will it fix invalid JSON automatically?
No. Invalid text is rejected. The tool does not guess corrections that could change your data.
Is JSON minification encryption?
No. Removing spaces does not secure sensitive information.
Clear the editor and check UTF-8 size
Use Clear input to empty the current JSON text and start over. The live size indicator shows input and output in UTF-8 bytes, not simply the number of visible characters. Unicode symbols can use several bytes each, so the 1 MiB input and 2 MiB output limits are measured on encoded data. No document is uploaded.
The tool rejects invalid JSON and numeric values that cannot be preserved by JavaScript without silent precision loss. For identifiers with many digits, encode the value as a JSON string instead. For CSV conversion, use the separate CSV-to-JSON tool.