JSON Formatter
Format, validate and beautify JSON data instantly.
Formatting happens entirely in your browser. Nothing you paste here is sent to a server.
How the formatter and validator workHow it’s calculated
This tool uses the browser’s own built-in JSON.parse() function to check your input. If the JSON is valid, it gets rebuilt with JSON.stringify() using 2-space indentation for Format, or no whitespace at all for Minify. Because it relies on the same parser every JavaScript engine uses, the validation is exact — if this tool accepts your JSON, it will work in any standard JSON consumer.
When the JSON is invalid, the error message shown is the same one the browser’s JavaScript engine generates internally — usually pointing to roughly where the syntax broke (an extra comma, a missing quote, an unclosed bracket). It won’t catch every issue with perfect precision on deeply nested structures, but it will always tell you the JSON failed and roughly why.
This is the everyday tool for anyone debugging an API response, cleaning up a config file, or double-checking JSON before it goes into a script or a request body — paste it in, format it, and you can immediately see the structure and spot what’s wrong.
JSON Formatter — FAQ
What does “Invalid JSON” actually mean?
It means the text you pasted doesn’t follow JSON syntax rules exactly — a common cause is a trailing comma after the last item, missing quotation marks around a key, or an unclosed bracket or brace.
Does this validate JSON Schema, or just JSON syntax?
Just syntax. This checks that your JSON is structurally valid (correctly nested brackets, quoted keys, proper commas) — it doesn’t check it against a specific schema or expected data shape.
Is there a size limit on how much JSON I can format?
There’s no hard limit built into the tool, but very large files (multiple megabytes) may feel slower since everything runs in your browser’s memory rather than on a server.
Is my JSON data sent to a server?
No. Parsing and formatting both happen locally using your browser’s built-in JSON engine. Nothing is uploaded or logged.