Programming tool
JSON Formatter & Validator
Check JSON syntax, make it readable, or compress it for use in an API request. Everything runs locally in your browser.
Paste JSON to begin.
Processed locally in your browser. Your JSON is not uploaded.
What is JSON?
JSON, or JavaScript Object Notation, is a text format for representing structured data. It uses objects with name-value pairs and arrays, plus strings, numbers, booleans, and null.
What does a JSON formatter do?
A formatter parses valid JSON and adds indentation and line breaks so nested data is easier to inspect. Minifying reverses that presentation by removing unnecessary whitespace.
Formatting vs. validation
Validation answers whether the text follows JSON syntax. Formatting can only happen after parsing succeeds, so a failed format is also a useful validation signal. Neither action changes the meaning of valid data.
Common JSON syntax errors
Check for double quotes around property names and strings, commas between items, no trailing commas, and matching braces and brackets. JSON also requires lowercase true, false, and null.
Frequently asked questions
Is my JSON uploaded anywhere?
No. This tool uses your browser's built-in JSON parser and does not send your input to a server.
What is the default indentation?
Valid JSON is pretty-printed with two spaces per level.
Can JSON use single quotes?
No. Standard JSON requires double quotes for strings and object keys. Single quotes are valid in some programming languages, but not in JSON.