Paste JSON
Enter an object, array, string, number, boolean, or null value that follows the JSON data format.
JSON Formatter & Validator
Beautify hard-to-read JSON, validate its syntax, or minify it for transport.
How to format or validate JSON
Turn compact JSON into readable indentation, check its syntax, or remove whitespace before moving data between applications.
Format or minify
Format adds two-space indentation. Minify removes nonessential spaces and line breaks.
Fix any syntax error
If parsing fails, use the reported browser error to locate issues such as missing quotes, commas, or brackets.
Format JSON without exposing application data
All parsing and formatting happens in your browser. That makes the tool useful for configuration, logs, webhook examples, and API responses that should not be pasted into a remote processing service.
The formatter parses the input and serializes it again with consistent two-space indentation. Minification performs the same validation before returning compact JSON, so invalid syntax is never silently reformatted.
Common JSON syntax problems
- Property names must use double quotes.
- Items require commas, but trailing commas are not valid JSON.
- Strings cannot contain unescaped line breaks.
- JSON does not support comments or JavaScript values such as
undefined.
Frequently asked questions
What does validation check?
The tool uses the browser's standards-based JSON parser and reports the first syntax error it encounters.
What does minify do?
It removes unnecessary spaces and line breaks while preserving the parsed data and validating the syntax.
Is pasted JSON uploaded?
No. The JSON stays in the current browser tab and is not sent to FreNiMi.
Why are comments rejected?
Comments are allowed in some configuration formats, but they are not part of the official JSON syntax.
Is there a size limit on the JSON I can paste?
No hard limit, but parsing runs on the main thread, so a very large payload (tens of megabytes) can briefly freeze the tab while it processes.