What is JSON?
JSON Syntax Rules
JSON (JavaScript Object Notation) is a lightweight data format. Data is in key/value pairs separated by colons. Items are separated by commas. Objects use curly braces {}, arrays use square brackets []. Strings must use double quotes (not single). Keys must also be strings in double quotes.
Common JSON Errors
Trailing commas after the last item in an object/array are invalid in JSON (unlike JavaScript). Single-quoted strings cause parse errors. Missing quotes around keys, unescaped special characters in strings, and comments (JSON doesn't support comments) are all common mistakes.
Frequently Asked Questions
Is my JSON data safe when using this tool?
Yes — 100% safe. All JSON processing happens in your browser using JavaScript. Your data never leaves your device and is never sent to any server. You can even use this tool offline after the page loads.
What's the difference between JSON and JavaScript objects?
JSON requires double quotes for both keys and string values, doesn't allow trailing commas, doesn't support functions or undefined values, and doesn't allow comments. JavaScript objects are more flexible but JSON is a universal data format supported by all programming languages.
Why should I minify JSON?
Minifying JSON removes all unnecessary whitespace and newlines, reducing file size significantly. This speeds up API responses and reduces bandwidth usage. Minified JSON is harder to read but identical in data to formatted JSON.