JSON Formatter & Validator
Beautify, minify, and validate JSON, with a clear error message the moment something doesn't parse.
Runs entirely in your browser, nothing is uploadedFormat JSON in three steps
- Paste JSON into the input box, valid or not.
- Choose beautify for readable, indented output, or minify to strip all whitespace.
- If something doesn't parse, the error message points to what went wrong so you can fix it.
Why people use the JSON Formatter & Validator
Everything worth knowing before you dive in.
How it helps
Minified JSON straight from an API response or a config file is nearly unreadable, one long line with no indentation to show where objects and arrays begin and end. Beautifying it restores that structure instantly, while minifying does the reverse, useful right before shipping a config file where every byte counts.
Built for real use
When the input isn't valid JSON, the tool surfaces the parser's error message directly rather than failing silently, which usually points to a missing comma, an unclosed bracket, or a stray trailing comma, the most common mistakes when hand editing JSON.
Private by default
Everything runs through the browser's built in JSON parser, so formatting and validation happen instantly with no size limit beyond what your browser can comfortably hold in memory.
Pro tip
When debugging a validation error, minify first to collapse the file to one line, then beautify again, the reformatted indentation often makes a misplaced bracket or comma much easier to spot.
Common questions
What causes a JSON validation error?
The most common causes are trailing commas, missing quotation marks around keys, or an unclosed bracket or brace.
Is there a size limit on the JSON I can paste in?
There's no fixed limit, though very large documents depend on your browser's available memory.
Does minifying change the data?
No, minifying only removes whitespace and line breaks. The underlying data structure stays exactly the same.