JSON Formatter
Format, validate and minify JSON instantly. Find syntax errors with the approximate line and column.
100% in your browser — nothing is sent to any serverFormat JSON
What is JSON?
JSON (JavaScript Object Notation) is a lightweight text format for exchanging data. Although it derives from JavaScript, it is language-independent and is used in APIs, configurations, logs, and databases. Its basic structures are objects {}, arrays [], strings, numbers, booleans, and null.
Most common syntax errors
- Trailing commas at the end of arrays or objects.
- Unquoted keys: JSON requires
"key", not'key'. - Strings wrapped in single quotes instead of double quotes.
- Comments
//or/* */, which are not allowed in standard JSON.
Frequently asked questions
What does a JSON formatter do?
It takes compact or messy JSON and rewrites it with indentation and line breaks so it is easier to read and debug.
Does it also validate?
Yes. If the JSON is invalid, it shows the error message and tries to indicate the approximate line and column where the problem is.
What are the most common errors?
The most common ones are trailing commas in arrays or objects, single quotes instead of double quotes, and unquoted keys. Comments are also not allowed in standard JSON.
Is there a size limit?
Only your browser's memory limit. For very large JSON, formatting may take a few seconds.
Is my JSON uploaded to a server?
No. All processing happens in your browser; the JSON never leaves your device.