JSON formatter and validator
Make JSON readable, and find out exactly what’s wrong when it isn’t valid.
Report a problem with this tool
How to use JSON formatter
Paste your JSON
Paste JSON, or open or drop a .json file. It’s checked as you type.
Choose a layout
Indent with 2 or 4 spaces or a tab, or minify it to one line. Tick Sort keys A–Z to put keys in order.
Copy or download
Copy the formatted JSON, or download it as formatted.json.
Why use Utils365
Errors you can fix
Invalid JSON shows the line and column of the mistake, with the line itself and a pointer, plus a hint for trailing commas, single quotes, unquoted keys and comments.
Pretty print or minify
Choose 2 spaces, 4 spaces or tabs for reading, or squeeze it onto one line to save space.
Nothing changes but the layout
Numbers, text and key order come out exactly as written, unless you choose to sort keys A–Z to make two files easier to compare.
Private by design
Your JSON is checked and formatted in your browser and never uploaded, so API keys and customer data stay with you.
Frequently asked questions
How do I check if my JSON is valid?
Paste it in. Valid JSON shows a summary with the number of keys and how deeply it nests. Invalid JSON shows the line and column of the first mistake and what to change.
Why is a trailing comma an error?
JSON doesn’t allow a comma after the last item in an object or array, even though JavaScript does. Remove the comma before the closing } or ].
Can JSON have comments or single quotes?
No. Standard JSON has no comments, and strings and keys must use double quotes. Formats like JSON5 and JSONC allow them, but most APIs and parsers don’t.
Will my numbers or key order change?
No. Numbers keep exactly the digits you wrote, so long IDs like 1234567890123456789 and prices like 1.10 come out unchanged. Keys stay in their order unless you tick Sort keys A–Z.
What does minify do?
It removes every space and line break that isn’t inside a string, so the JSON is as small as possible. The data is exactly the same.